ABSTRACT Title of Dissertation:ANALOGIES AS CATEGORIZATION PHENOMENA: STUDIES FROM SCIENTIFIC DISCOURSE Leslie Jill Atkins, Ph.D., 2004 Dissertation Directed By:Associate Professor David Hammer, Department of Curriculum and Instruction, Department of Physics Studies on the role of analogies in science classrooms have tended to focus on analogies that come from the teacher or curriculum, and not the analogies that students generate. Such studies are derivative of an educational system that values content knowledge over scientific creativity, and derivative of a model of teaching in which the teacher?s role is to convey content knowledge. This dissertation begins with the contention that science classrooms should encourage scientific thinking and one role of the teacher is to model that behavior and identify and encourage it in her students. One element of scientific thinking is analogy. This dissertation focuses on student-generated analogies in science, and offers a model for understanding these. I provide evidence that generated analogies are assertions of categorization, and the base of an analogy is the constructed prototype of an ad hoc category. Drawing from research on categorization, I argue that generated analogies are based in schemas and cognitive models. This model allows for a clear distinction between analogy and literal similarity; prior to this research analogy has been considered to exist on a spectrum of similarity, differing from literal similarity to the degree that structural relations hold but features do not. I argue for a definition in which generated analogies are an assertion of an unexpected categorization: that is, they are asserted as contradictions to an expected schema. ANALOGIES AS CATEGORIZATION PHENOMENA: STUDIES FROM SCIENTIFIC DISCOURSE By Leslie Jill Atkins Dissertation submitted to the Faculty of the Graduate School of the University of Maryland, College Park, in partial fulfillment of the requirements for the degree of Doctor of Philosophy 2004 Advisory Committee: Associate Professor David Hammer, Chair Dr. Andy Elby Associate Professor Sarah Eno Professor Edward F. Redish Assistant Professor Emily van Zee ? Copyright by Leslie Jill Atkins 2004 ii Dedication For women in physics. ?As I say, I can speak only for myself, but as soon as I got here the rules became different. They didn?t apply to me any more, or to anyone else except a distant runt, almost invisible in its litter. So how was I to know who to stand up to, when to turn abrasive, when all things nestled, equidistant, all hearts were charming, and it was good to be natural and sincere?? School was over, not just for that day but forever and for seasons to come. The reason was that the truth was just average on the iniquity scale, and nobody wanted to get involved? You see we all thought the ride would be lovely and worth the trip, which it was, but now we cannot go anywhere having already been everywhere. No, do you understand how realistic it all is?? And so we faced the new day like a pilgrim who sees the end of his journey deferred forever. Who could predict where we would be led, to what extremes of aloneness? Yet the horizon is civil. -Ashbery, Girls on the Run iii Acknowledgements The idea behind this thesis is that the theories we develop with our science are analogies to the stories that we tell with our lives. And so this dissertation holds a mirror to my life and reflects its stories ? the stories that have brought me here and brought about this work. And those stories have as much to do with community and friendship as they do physics and education. I would like to acknowledge all of my friends, in particular Dorothy, Kathryn, Noam and Sam, for conversation about the things that matter, and my Seattle roommates ? especially Amber, Laura, Manu and Sam ? for creating a true home. I would like to thank Jerry Seidler, in whose lab I discovered that I did not want to do experimental physics and I was given the freedom and support to decide that. I thank Stamatis Vokos, the deus ex machina of my story, and Joe Redish, both of whom took risks for me and I am grateful for and buoyed by their trust. Graduate students Matty, Paul and Rosemary provided hours of critique and conversation in helping me hone the details of this thesis and kept me smiling through the massive frustrations. And friends outside of graduate school, Wendy and Anne in particular, reminded me of life beyond academia, while the Elliott family gave me hope that academia could be everything I wanted it to be. Were it not for my education at the Governor?s School of North Carolina, both as a student and a teacher, I would never have seen myself as someone with a story to tell or a theory to share. The work that happens there is incredible and profound. Thank you to Mrs. Liz Woolard, my brilliant high school physics teacher. And to Janet Coffey who is going to be an amazing professor and advisor and was so encouraging ? especially in the final stretch. The teachers from SIPS iv I cannot thank enough; without their careful attention to students and remarkable work as teachers there would be no data and no thesis. For all of the Physics Education Research Group, past and present: Renee Michelle, Tom, Rosemary, Matty, Paul, Ray, Tim, Paul, Jonathan, Rebecca, Loucas, Rachel, Laura, David, Joe, Andy, Emily and David. You are the greatest evidence of my thesis that science is influenced by the stories you tell with the rest of your life ? the stories you have given me have created the science in this thesis. These are stories of authenticity, theoretical inquiry, identity, frames and epistemology, of course, but also stories of communication, big hearts, laughter, dedication, teaching, birthday cakes, cicada roasts and community. And with all my heart a thank you to David Hammer, whose attention to and excitement about students? ideas, which I first witnessed with regard to elementary students, applies to graduate students as well. He has given me the voice that I had hoped graduate school would and feared that it wouldn?t. For Richard, you know my whole story ? told over lunches in the physics courtyard, driving across the country, along the West Coast Trail, in Chamonix, Bear Lake, Mazama, and, too many times, over the phone late at night. I am so lucky. You're for me. And finally, for my family: mom, dad, Sara and Ben. Thank you. Your love is tremendous. v Table of Contents Dedication ??????????????????...????????ii Acknowledgements ???????????????????????.iii Table of Contents ???????????????...????????.v Chapter 1: ???????????????????????????1 Introduction ????????????????????...????...1 A brief history of analogy research ????????????????4 Major themes ????????????????????????...5 Chapter overview ???????????????????????.6 Chapter two: Review of the literature ???????????????6 Chapter three: Origins of the study and methodological considerations ???.7 Chapter four: Phenomenological coherence ?????????????7 Chapter five: The ontology of mind ???????????????...8 Chapter six: Analogies in the history of science ???????????..8 Chapter seven: Implications for instruction ?????????????.8 Chapter eight: Summary and directions for future research ???????..9 Appendix A ? J: Transcripts 1 ? 10 ????????????????10 Appendix K: Young children?s analogies ?????????????...10 Chapter 2: Review of the Literature ?????????????????12 Introduction and overview ???????????????????...12 Analogies ??????????????????????????.15 Analogies in philosophy and the philosophy of science ????????...15 Analogies in cognitive science ?????????????????...17 Analogies in linguistics ????????????????????.19 Analogies in science and science education ?????????????20 Summary of analogy research ??????????????????23 Categorization ????????????????????????..24 Overview ?????????????????????????.24 Categorization and fuzzy sets ??????????????????25 Rosch and prototype theory ??????????????????...27 Properties of categories ????????????????????.29 Idealized cognitive models ???????????????????31 Metonymy, cognitive models and phenomenological-primitives ?????..33 Summary of categorization research ???????????????...35 Analogies as categorization ???????????????????.35 Metaphors as category-inclusion statements ????????????...35 Idealized cognitive models and lexical networks ???????????.38 Reconciling categorization and structure mapping views of analogies ???..40 Conclusion ?????????????????????????...40 Chapter 3: Origins of the Study & Methodological Considerations ????...43 Origins of the study ??????????????????????..43 History of research on analogies ?????????????????..45 vi Past research ????????????????????????45 Limitations of past methodology ?????????????????48 Recent approaches to the study of analogical reasoning ????????.52 Methodology ?????????????????????????54 A note on the data ??????????????????????55 The case study methodology ??????????????????.55 Summary ??????????????????????????..57 Chapter 4: Phenomenological Coherence ??????????????...58 Introduction ?????????????????????????..58 Models of analogy from the literature ???????????????58 Analogies as categorization ??????????????????...60 Multiple analogies ???????????????????????62 Multiple analogies: Example 1 ?????????????????..62 Multiple analogies: Example 2 68 Chains of analogies ????????????????????.??.71 Chains of analogies: Example 1 ?????????????????.72 Chains of analogies: Example 2 75 Chains of analogies: Example 3 ?????????????????.76 Construction of the base ????????????????????...80 Depiction of the base in research on analogies ????????????80 Prototypes in categorization ??????????????????..81 Construction of the prototype ??????????????????82 Construction of the base in student-generated analogies ????????..83 Near and far transfer analogies ??????????????????86 Research on prototypes and research on transfer ???????????.86 Examples from student-generated analogies ????????????...87 Variable representation of the base ????????????????..88 Variable representation: Example 1 ????????????????89 Variable representation: Example 2 92 Previous claims of analogy as categorization ????????????..97 Analogies as negative assertions ?????????????????.98 Violations of expected schemas ?????????????????.98 Examples from student-generated analogies: Analogies as negative assertion ?99 Conclusion ?????????????????????????..101 Chapter 5: The Ontology of Mind ?????????????????. 105 Introduction ?????????????????????????. 105 History of ontology of mind and description of the chapter ??????... 105 Section 1: A theoretical account of the ontology of mind ???????.. 107 Structure-mapping ?????????????????????... 107 The arguments for variability in conceptual representations ??????? 109 Structures in a manifold ontology of mind ?????????????. 113 Interlude: A distinction between similarity and analogy ???????? 117 The conflation of similarity and analogy in past definitions ???????117 A proposed definition of analogy as a change of schema ???????? 122 Section 2: The base of generated analogies as representations of a schema . 125 vii Schemas and p-prims in the cup/water analogies ..??????????.. 125 The Beanbag Analogies ???????????????????... 132 Styrofoam and Ice Skating ?...????????????????? 136 Analogies regarding a quantum mechanics problem ?????????... 142 The ontology of authenticity ??????????????????. 144 Conclusion ?????????????????????????.. 146 Chapter 6: Analogies in the History of Science ????????????. 148 Introduction ?????????????????????????. 148 History and philosophy of science ????????????????.. 151 Comparative literature ????????????????????... 154 Membranes ????????????????????????. 155 Networks ????????????????????????? 158 Luca Turin: Analogies involving scent ??????????????.. 162 Cognitive science ??????????????????????? 164 Conclusion ?????????????????????????.. 168 Chapter 7: Implications for Instruction ???????????????.. 170 Introduction ?????????????????????????. 170 A critique of standard analogy use in classrooms ??????????.. 171 Implications for instruction ???????????????????. 177 Students ought to generate their own analogies ???????????.. 177 Expect variability and multiple analogies ?????????????.. 180 A reconsideration of the idea of transfer ?????????????? 182 An example of these implications for instruction in practice ??????. 184 Examples from transcripts ??????????????????? 184 Examples from the literature ??????????????????. 185 An example from my own teaching ???????????????... 186 Finding analogies in the classroom ????????????????. 193 The National Science Education Standards ????????????? 195 The case for diversity in science ?????????????????. 196 Conclusion ?????????????????????????.. 197 Chapter 8: Summary & Directions for Future Research ????????? 198 Introduction ?????????????????????????. 198 Summary ??????????????????????????. 199 Negative analogies ??????????????????????.. 200 Literary analysis and differ?nce ????????????????? 200 Negative analogies ?????????????????????.. 202 Negative analogies in physics ?????????????????... 204 Negative analogies as a caveat ?????????????????.. 205 Directions for future research regarding analogies and mind ??????. 206 The changing schema ????????????????????... 206 Conceptual blending ????????????????????? 207 The implications of technology on science ????????????? 207 Science in the absence of analogy ????????????????. 208 Embodied cognition and analogies in science ???????????? 209 Analogies as a tool for exploring categorization ???????????. 210 viii Network theory and analog ??????????????????... 210 Directions for future research on the implications for instruction ????.. 212 Questions regarding student epistemology ?????????????. 212 The design of learning environments???????????????.. 212 Concluding thoughts ?????????????????????... 213 Appendix A ? J: Transcripts ???????????????????.. 215 Appendix K: Young children?s analogies ??????????????.. 292 Glossary???????????????????????????..302 Bibliography??????????????????????????304 Curriculum Vitae????????????????????????.312 1 Chapter 1: Introduction and Major Themes Introduction Metaphor is the currency of knowledge. I have spent my life learning incredible amounts of disparate, disconnected, obscure, useless pieces of knowledge, and they have turned out to be, almost all of them, extremely useful. Why? Because there is no such thing as disconnected facts. There is only complex structure. And both to explain complex structure to others and, perhaps more important ? this is forgotten, usually ? to understand them oneself, one needs better metaphors. If I was able to understand this, it was because my chaotic accrual of information simply gave me better metaphors than anyone else? Translate a concept from its field for use to where it is unknown, and it is always fresh and powerful. In buying outside, you are doing intellectual arbitrage. The rate limiting step in this is your willingness to continuously translate, to force strange languages to be yours, to live in between, to be everywhere and nowhere. -Burr, 2002 Many scientific theories evolve from analogy ? noticing links others have missed or relating a fact that others have not noticed. Luca Turin (Burr, 2002) related the mechanism for smell to electron tunneling spectroscopy. The arguments and evidence for his model came not from chemistry or biology, but perfumery and jet fuel technology. Einstein was a patent clerk in an era when trains were fast becoming a primary means of transportation. Many patents of this time concerned synchronizing clocks, and Galison has proposed that considering this problem in the context of what Einstein knew from physics led him to his theory of relativity (Galison, 2003). Faraday?s research notes express deep analogical reasoning: thinking of electro-magnetism in terms of lines in space (the ?field concept?) (Nersessian, 1985). Maxwell related magnetism to vortices and ?idle wheels? (Nersessian, 2002). Kosterlitz and Thouless (1973) related 2- 2 dimensional phase transitions to topology. The scientific literature is overrun with breakthroughs that developed from analogical reasoning ? relating seemingly unrelated topics that, once related, establish a new research paradigm. The use of analogies in science is not restricted to insights from creative scientists, but is part of the regular patter of students and instructors when discussing scientific ideas. In the following transcript, undergraduates in a conceptual physics course have been exploring static electricity in conductors and in insulators. The students have worked in small groups, discussing the differences between what it?s like for a charge in metal versus Styrofoam, and are now reporting and discussing their conclusions with the instructor (transcript 1, lines 41 ? 107): Christie: Like they were just saying in metal it?s [the charge is] always moving. So if it?s always moving it has more room to move and that would mean to say that the molecules are, like, less tightly packed together or less dense. And we were thinking of Styrofoam as more dense then ? I?m just trying to figure out first if that?s right and how it relates. Lea: Alright I, going on that idea. I don?t agree with you saying that the Styrofoam is more dense I think it's less dense. And so that?s why the charges get caught up in it. 'Cause it's like ? like cotton. And the, the pan is more dense and so they?re able to slide across it like they can ice skate across it easier. So that?s why they move around more 'cause it?s more dense so they can slide across it more and the Styrofoam is less dense and so they get stuck in it. Like they can?t move as much. Instructor: ? I?m thinking of like, pouring water into a sponge versus pouring water onto a hard surface. Like this sponge is actually less dense and there?s room for it to absorb the water and the you know if you pour it onto something hard there?s no room for it to absorb. Anna: You?re saying that the charge is, like, on top of the metal? Like on the outside? Lea: Yeah. Hold on-I mean-I don?t- Anna: I think it?s like made up of it-like, they?re electrons. Lea: Like, I don?t know. But it?s definitely a lot smoother, like, and they?re they?re denser and so they can move around more freely. 3 Paul: I just want to- I know there are people here- I just want to clarify Lea and Anna your question, your question was ?Is charge moving on the surface as opposed to moving inside.? Right? And so this would be like are the fish swimming in the middle of the fishbowl or are they sort of somehow stuck to the edge of the fishbowl? Lydia: Alright, well I was going to say it makes sense to me if the pie plate is more dense, then it would be easier for them to move within it. But I do think that it?s inside of the metal not outside. Because it?s harder- I mean, if there?s more space to travel like in the foam, you can?t get from one place to another easily but it?s all real close together so it can sort of hop along inside. Paul: Oh so it?s like stepping stones? Lydia: Kind of. Paul: Like in the Styrofoam it?s really far [Lydia: Like yeah.] to the next stepping stone and so I can?t get there I?m stuck here. [Lydia: Right] But in the metal the stones are really close together and so then I can kind of just walk across. Notice the analogies drawn in the brief transcript above: the motion of electrons in metal is like ice-skating, the metal is like a countertop or closely spaced stepping-stones. Styrofoam is like a sponge or cotton. What cognitive work does this do for the students? Why are these analogies chosen? How do they influence the resulting theories the students develop? What do these analogies reveal about the way the students conceptualize the world? There is no shortage of research to turn to in addressing these questions and seeking to understand analogies in science. Research from education, cognitive science, linguistics, anthropology, and the history and philosophy of science all have something to say about the analogies that the scientists and students are employing. This dissertation draws from all of these fields, together with analogies generated by students in science classrooms and study groups, in constructing a model for generated analogies in science and explores the implications of this model on science instruction. A brief history of analogy research 4 What cognitive capabilities underlie our fundamental human achievements? Although a complete answer remains elusive, one basic component is a special kind of symbolic ability ? the ability to pick out patterns, to identify recurrences of these patterns despite variation in the elements that compose them, to form concepts that abstract and reify these patterns, and to express these concepts in language. Analogy, in its most general sense, is this ability to think about relational patterns. -Holyoak, Gentner and Kokinov, 2001 Analogies, long recognized as being far more than figurative, expressive forms of speech, have frequently been used as tools for teaching students about science (Clement, 1993, Gick and Holyoak, 1983) and the benefits of this has been explored extensively. The story that this research tells suggests that the base of the analogy ? the sponge, say, or the stepping-stones in the transcript above ? is the cognitive foundation for the analogy. It is from this base that students extrapolate a structure and map onto a target. But there are several things problematic with this story when applying it to student-generated analogies in classrooms. First, the story contradicts other findings from education that inform us that we do not have single, unitary representations of concepts in mind that can be mapped onto others. Second, it is a model built from studies regarding how students interpret and understand analogies that they are given ? or even how we, as teachers, come to understand their analogies ? but not the things students are doing when they assert analogies. If generating, critiquing and working with analogies are part of the practice of science we want students to learn, we need to better understand moments like the one above, in which students generate analogies and the analogies introduced by the instructor are responsive to student ideas rather than content goals. Because of the focus on the interpretation of analogies less well known, researched and 5 understood are the ways in which analogies are constructed by students seeking to explain the world in a scientific way (May, Hammer and Roy, 2004). Major themes The story I want to tell, using analogies generated in student scientific discourse and in science as it is practiced, is one of analogies as assertions of categorization ? in particular, a categorization that is unexpected. Categories, as I will explain in the following chapter, stem from our cognitive models of the world, built from schemas. Lea?s analogy to ice-skating (presented at the beginning of this chapter) is, first, an acknowledgement that density typically makes motion difficult. Her analogy is asserting that another manner of categorization exists for dense media: there are those that, by virtue of their density, make motion easier. The interpretation of analogies as assertions of categorization echoes Eva Feder Kittay's (1997) comments with regard to metaphor ? made in the field of linguistics, outside of physics and education. If metaphors do not report an antecedent similarity, but instead create the similarity, they do so by dislodging some items from familiar classifications and regrouping them with items that normally belong to different, even disjoint categories. So dislodging and regrouping items or subclassifications not only creates a new category, but also disrupts normal classifications. This thesis will outline the reasoning behind the ?normal classifications? that we have, based on Lakoff?s research in idealized cognitive models and diSessa?s theory of phenomenological primitives. Furthermore, the bases of analogies are explained in this context as arising from the categories that are constructed from cognitive models and are the ad hoc, constructed prototypes of these categories. The ontology of mind implicit in this theory is compared with other theories of analogy, in particular structure-mapping (Gentner, 1983). I argue for a manifold, small 6 scale, ?knowledge-in-pieces? ontology of mind and support this argument with data from other findings in cognitive science, linguistics and education. Finally, this thesis has strong implications for instruction, education research and cognitive science, starting from the premise that generating analogies should be an important part of the science classroom ? not as a tool for acquiring content knowledge but as a goal of a science education because it is, in part, what science is. Second, the focus on interpreting analogies and lack of attention to generated analogies is challenged: such a focus misses the cognitive flexibility and utility of most analogies, as analogies are surely generated more often and with greater effect than they are interpreted. Third, the ideas underlying ?transfer? and ?misconceptions?-based curricula are called into question. Finally, I caution research ? in particular education research ? against ?in vitro? studies that are not balanced by ?in vivo? studies of cognition in the wild. Applying findings generated in laboratories that limit cognitive variability and lack the context of a classroom to educational and other ?real world? scenarios can result in a detrimental shift of focus from students? abilities and the variability of student reasoning to a focus on a unitary conception of students? reasoning and abilities. Chapter overview Chapter Two: Review of the literature In the following chapter, I will outline the existing research on analogies and categorization. My emphasis is on the characteristics of generated analogies and categorization, and not by what mechanism the mind creates schemas and their associated categories. I present research from cognitive science and linguistics on analogies and metaphors and the role that analogies have played in science education. Then I outline 7 the research on categorization and the interplay between categories and idealized cognitive models. Research from physics education on phenomenological primitives is then related to the idealized cognitive model. Finally, past research relating analogies to categorization is reviewed. Chapter Three: Methodological Considerations This chapter is dedicated to outlining the history of research in analogical reasoning and situating my methodology within this history. In particular I focus on the methodology of past research and the kind of information that this methodology affords. The limitations of laboratory-based studies are addressed along with the philosophy of mind and of causality that are inherent to these studies. I then overview more recent studies of analogy and the more qualitative methodologies of these along with the advantages and limitations of these approaches. I then explain the approach that I take, the philosophy behind this approach and the information that can and cannot be gleaned from this research. Chapter Four: The phenomenological evidence A distinction has been made in the literature between behavior ? the observable part of cognition ? and cognitive structure ? the underlying ontology of mind responsible for that behavior. Chapters four and five address these two sides of cognition, chapter four focusing on cognitive behavior and five on the underlying cognitive structure. In this chapter I first review past research on categorization, focusing on the observable structure of categories, and contrast that with existing research on analogies. I then present transcripts from students in science classrooms, study groups, research groups and faculty and present an argument for the interpretation of analogies in a categorization 8 framework, basing this interpretation on the behavior. These claims will be contrasted with other models of analogy, in particular structure-mapping and transfer. The analogies discussed here will be explored again in the following chapter for their implications on cognitive structure. Chapter Five: Cognitive structure and analogies Having presented phenomenological evidence for analogies as categorization, in this chapter I focus on the underlying cognitive structure that can account for that behavior and is consistent with a categorization interpretation of student-generated analogies. I begin this chapter with a review of the different approaches that have been taken in the past to cognitive structure in both education and cognitive science and present arguments in favor of a manifold ontology of mind. Analogies presented in the previous chapter are then revisited for their consistency with this manifold ontology. Chapter Six: Analogies in the history of science Though this thesis does not focus on the history of science and the evolution of scientific theories, several findings from the history of science can be brought to bear in defense of my claims. In this chapter, I briefly outline research in the history of science and cite several theories and ideas that have evolved via analogy. These ideas demonstrate that important concepts in science arose from schemas provided by changes in our political systems and our technology. I outline these theories and their development and show how it is consistent with a categorization model of analogy. Finally, I show how a study in the history and philosophy of science has changed the definition of a concept and how this new definition, which is rooted in the idea of 9 conceptual change via physical analogy, is consistent with the categorization framework of generated analogies. Chapter Seven: Implications for instruction. There are three main points that I would like to make with regard to science instruction with this thesis. The first point reflects my motivation behind studying student-generated analogies: the use of analogies and analogical reasoning is, in large part, what it means to do science. Content knowledge of the science disciplines is important, but even more so is the ability to think scientifically: to be able to understand that content knowledge as it relates to theories and experiences that you have, to be able to create your own models using analogies to concepts that you understand and find familiar, to understand the implications of these models and negotiate these analogies: in essence, to create your own knowledge from your own experience in a scientific manner. If we accept this first claim, that science instruction should emphasize how to create and negotiate analogies, our conception of what analogies are matters and will influence the way in which a teacher identifies and responds to analogical reasoning in the classroom. The second point, then, is that analogies are not indicative of a fixed representation of a particular concept. The mind is far more fluid and complex than that. Understanding analogies as assertions of categorization requires that instruction be sensitive to this variability, for categories are inherently variable. And third, by understanding analogies as assertions of categorization, questions of transfer ? the holy grail of education ? become not questions of near and far transfer, but of prototypical and aprototypical analogies. How this translates into practice will be explored in further detail in this chapter. 10 Chapter Eight: Directions for future research and conclusion. While I make claims about what analogies assert, I have not come to any conclusions about how this happens. What habits of mind and what structure of education and environment can encourage this kind of creative re-categorization of concepts? Nor do I explore theories that are not built from analogy or have no obvious analog or the extremely significant role that community and dialog plays in both constructing and negotiating an analogy. In the final chapter, I summarize my conclusions and introduce these questions and suggest directions for future research on these topics. Appendix A-J: Transcripts Included in the appendix are full transcripts from conversations in which the analogies presented in the dissertation are taken. These transcripts are referenced in the chapters, so the reader may find the entirety of the transcript that I had available. In some cases, these transcripts span entire class-periods of discussion; in other cases, only a short piece of that conversation exists. Appendix K: Young Children?s Analogies and Transcripts Chapters 4 and 5 presented several analogies from student conversations in science, and chapter 6 details analogies by professionals in science and related fields. In the appendix I address analogies that were not included in previous chapters, particularly those asserted by younger students. These students are able to generate analogies (for example, magnets are like clay) but lack explicit awareness of that analogy. These students are confused by the mapping to the target, or confuse the assertion with literal class inclusion (so that magnets are not like clay but are clay). This confusion is 11 consistent with findings from Karmiloff-Smith (1992) on representational redescription and is predicted by Glucksberg?s et al. (1997) dual reference theory. Structure-mapping and other theories that limit analogies to pairwise analyses of the target and base would not predict and cannot account for the confusion young students show between statements of class-inclusion and statements of superordinate-class-inclusion. This chapter presents theories and findings of representational redescription, dual reference, semantic fields and polysemy and argues that, in light of those findings, the mistakes and confusions that young students display with analogies are consistent with a categorization interpretation of analogy. 12 Chapter 2: Review of the Literature Introduction and Overview In the latter half of the 20 th century research in two fields, categorization and analogy, has challenged long held classical views of these topics. Up until the nineteenth century, discussions on analogy, and in particular metaphor, were insistent on one theme: analogies are decorations of speech; they do not contribute to the cognitive meaning of the discourse, but instead lend it color, vividness, emotional impact, or accessibility. Thus it was characteristic of the Enlightenment philosophers and their predecessors, such as Hobbes and Locke, to insist that though philosophers may sometimes have good reason to communicate their thoughts with metaphors, they should do their thinking entirely without metaphors. Only by using nothing but unambiguous, literal language could knowledge be gained and communicated properly (Hobbes, 1651): To conclude, the light of humane minds is perspicuous words, but by exact definitions first snuffed, and purged from ambiguity; reason is the pace; increase of science, the way; and the benefit of mankind, the end. And, on the contrary, metaphors, and senseless and ambiguous words are like ignes fatui; and reasoning upon them is wandering amongst innumerable absurdities; and their end, contention and sedition, or contempt. Similarly, John Locke, in the Essay Concerning Human Understanding, criticized imprecise and ambiguous ?civil? language and proposed a proper and well-defined philosophical language that ?may serve to convey the precise notions of things, and to express in general propositions certain and undoubted truths, which the mind may rest upon and be satisfied with in its search after true knowledge? (Locke, 1686). What characterizes almost all theories of metaphor from the time of the 13 Romantics up through the twentieth century is the rejection of this theme. Metaphors, it has been argued, are not cognitively dispensable decorations. They contribute to the cognitive meaning of our discourse and they are indispensable, not only to philosophical discourse, but to ordinary, and even scientific discourse. Nietzsche went so far as to argue that all speech is metaphorical and truth is ?a mobile army of metaphors? (Nietzsche, 1873). Lakoff and Johnson?s seminal work, Metaphors We Live By (1980), begins with the statement of traditional interpretations of metaphor and summarily reject this interpretation: Metaphor is for most people a device of the poetic imagination and the rhetorical flourish ? a matter of extraordinary rather than ordinary language? We have found, on the contrary, that metaphor is pervasive in everyday life, not just in language but in thought and action. Our ordinary conceptual system, in terms of which we both think and act, is fundamentally metaphorical. (p3) This shift in understanding of the importance of analogies ? from ornamental to fundamental ? has resulted in the emergence of research in the structure and comprehension of analogy. The results of this research will be addressed later in this chapter. Categorization, too, has experienced a dramatic reinterpretation in the 20 th century. As Lakoff summarizes in Women, Fire and Dangerous Things: What Categories Reveal about the Mind (p 6): From the time of Aristotle to the later work of Wittgenstein, categories were thought [to] be well understood and unproblematic. They were assumed to be abstract containers, with things either inside or outside the category. Things were assumed to be in the same category if and only if they had certain properties in common. And the properties they had in common were taken as defining the category. This classical theory was not the result of empirical study. It was not even a subject of major debate. It was a philosophical position arrived at on the basis of 14 a priori speculation. Over the centuries it simply became part of the background assumptions taken for granted in most scholarly disciplines. In fact, until very recently, the classical theory of categories was not even thought of as a theory. Current theories on categorization have shifted from this Aristotelian view towards what has become known as the ?prototype? view, the importance of which was first established by Rosch (1973). This shift in our understanding of categorization can be traced to the Whorfian hypothesis, which claims that language is not merely a medium for the expression of our thoughts but that ?linguistic patterns themselves determine what the individual perceives in this world and how he thinks about it. Since these patterns vary widely, the modes of thinking and perceiving in groups utilizing different linguistic systems will result in basically different world views? (Fearing, 1954). Rosch?s tests of the Whorfian hypothesis led her to study the nature of color categories among speakers of languages without a blue-green color distinction. In these studies, she identified structure within categories, with some members of a category being seen as more or less prototypical than others. This recognition, with its associated research paradigm, launched a field of study into categorization that has come to be characterized as the ?prototype? view. More recent developments in this field have extended the types of categories studied from ?common, or stable, categories to ad hoc categories? (Shen, 1992) ? from Rosch?s study of color categories to Barsalou?s study of ?things to take from your house during a fire.? The results of this research and its implications on cognitive structure will be discussed later in this chapter. It has not gone unnoticed that these two research programs, analogy and categorization, are both studies of similarity and each may have insights that might inform the other, but as late as 1992 it was remarked: ?Despite the obvious affinity of 15 these two fields of research, the link between them has received little attention in cognitive psychology or in other disciplines? (Shen, 1992). Shen and others (most notably Glucksberg and Keysar), have, during the 1990?s, dedicated study to linking these two research enterprises. However, the emphasis of this research has been on metaphors and their interpretation, developing ?a coherent and unified framework by assuming that metaphor interpretation is, in fact, a process of ad hoc category formation? (Shen 1992), and ?a basis for a theory of metaphor comprehension, and also clarifies why people use metaphors instead of similes? (Glucksberg and Keysar, 1990). It is the aim of this thesis, in the context of scientific discourse, to extend the link between metaphor and categorization to include analogical statements and to argue that the statement of an analogy ? not merely its comprehension ? is an assertion of categorization. Below I will outline the existing research on analogies and categorization, along with the research that attempts to link these two fields of study, in more depth. Analogies Analogies in philosophy and the philosophy of science The modern views of analogy can be traced to the influences of philosophers Max Black (1962) and Mary Hesse (1966). Black?s work built on that of Ivon Richards? (1936) work in the field of rhetoric, who proposed a set of useful terms for talking about metaphors (the ?topic? or ?tenor,? the ?vehicle,? and the ?ground?) and a theory of how metaphors function. This theory, called the tensive view, emphasized the conceptual incompatibility, or ?tension,? between the terms (the topic and the vehicle) in a metaphor (Ortony, 1993). Black?s interpretation of metaphor, referred to as the interaction model, claims that metaphor is a cognitively irreducible phenomenon that works not at the level 16 of word combination, but much deeper, arising out of the interactions between the conceptual structures underlying words. In comparing two concepts, the significance of one concept is not merely projected onto another, but the two interact, altering the perception of both concepts. Explaining this theory in metaphorical terms, Black offers the following analogy (1962): Suppose I look at the night sky through a piece of heavily smoked glass on which certain lines have been left clear. Then I shall see only the stars that can be made to lie on the lines previously prepared on the screen, and the stars I do see will be seen as organized by the screen's structure. We can think of the metaphor as such as screen and the system of 'associated commonplaces' of the focal world as the network of lines upon the screen. In his theory, Black claims that the following are true of all metaphors (synopsis from Ortony, 1993): ? Metaphors consist of primary and secondary components. (In the statement ?X is like Y? X is referred to as the primary and Y the secondary. Other literature refers to these as the tenor, vehicle, target, etc., and there is no standard convention across disciplines. I will use base and target, recognizing that these make implications about the nature of analogical reasoning.) ? The significance of the base subject is not so much as a ?thing? as it is a system. ? The associated implications of the base are projected onto the target. ? This projection selects, organizes, emphasizes and suppresses features of the target component. Through this interaction of the two subjects there is a selection of properties, an implication on the target, and, reciprocally, an implication back on the secondary. This interpretation of metaphor, which is still central to many theories of metaphor, was incorporated four years later by Mary Hesse, a philosopher of science, whose ?treatise on analogy in science argued that analogies are powerful forces in discovery and conceptual change? (Holyoak, Gentner and Kokinov, 2001). This treatise, Models and Analogies in Science (1966), argued that ?the deductive model of scientific explanation should be modified and supplemented by a view of theoretical explanation as metaphoric 17 redescription of the domain of the explanandum.? Additionally, she coins three new terms in analogical reasoning: the positive, negative and neutral analogies. In positing an analogy, ?positive analogies? are known to transfer from the base to the target, ?neutral analogies? are possible elements of the base that are present in the target, and ?negative analogies? are elements that do not transfer. Analogies in cognitive science In the 1980?s, concurrent with Lakoff and Johnson?s work on metaphor, there was a shift in research from four-term analogies (of the type found in standardized tests ? a:b::c:d) to more complex analogies, such as those found in science and language. According to Holyoak, Gentner and Kokinov (2001), who were themselves pivotal in this shift, This exploration led to a more general focus on the role of experience in reasoning and the relationships among reasoning, learning, and memory, giving rise to an approach termed ? case-based? reasoning (e.g., Kolodner 1993). In contrast to rule-based approaches to reasoning (the approach that was dominant in AI at the time), case-based reasoning emphasized the usefulness of retrieving and adapting cases or analogs stored in long term memory when deriving solutions to novel problems. This work continued to adopt Black?s model of metaphor, most significantly the system of relations in the base of the analogy. Among the best-known models developed at this time is Gentner?s theory of structure-mapping (1983). In this model the central idea is that an analogy is a mapping of knowledge from one domain (the base) to another (the target) such that a system of relations that holds among the base objects also holds among the target objects. In interpreting an analogy, people seek to put the objects of the base in one-to-one correspondence with the objects of the target so as to obtain the maximal structural match? Thus, an analogy is a way of aligning and focusing on relational commonalities independently of the objects in which those relations are embedded. (Gentner and Jeziorski, 1993.) 18 From this model a computational model, the Structure Mapping Engine, was developed by Falkenhainer, Forbus and Gentner (1990). Holyoak and Thagard (1989) have a similar (ACME) program for analogies that is instead based on a connectionist network, but the underlying model of analogy is the same. It is important to note that these models will take two systems (for example, the solar system and the Rutherford model of the atom) and, as Falkenhainer, Forbus and Gentner (1990) describe, construct ?matching algorithms consistent with [the] theory.? In contrast to these models are those posited by Douglas Hofstadter and the Fluid Analogies Research Group (FARG) at Indiana University, beginning with Melanie Mitchell?s (1990) dissertation. Their computational models do not interpret a given analogy, but generate novel analogies. These models, Copycat, LetterSpirit and Metacat, are based on the thesis that mental activity consists of many tiny independent events and that the seeming unity of a human mind is merely a consequence of the regularity of the statistics of such large collections of events. Thus the metaphor of the ?intelligent ant colony? and the image of ?active concepts??have inspired our models for over two decades. The models all involve the nondeterministic interaction of many tiny events that take place in simulated parallel. The models also feature both long- term and short-term memories, the former of which houses permanent concepts, and the latter of which is like a stage on which temporary mental structures are built, modified, and eventually razed. Events in each memory profoundly influence the multiple tiny parallel processes, and in that way, each memory affects what goes on in the other. (Hofstadter, 2004) This thesis concerns itself with the creation of analogies, as opposed to their interpretation. I will show in later chapters that structure-mapping cannot account for analogy creation, and argue that the Hofstadter?s interpretation of cognition as ?many tiny independent events? is consistent with modern views on categorization, which are consistent with observed properties of student-generated analogies in science. 19 Analogies in linguistics Concurrent with this shift in cognitive science (and, in particular, artificial intelligence) from rule-based to case-based reasoning, the field of linguistics began a departure from traditional Chomskian emphasis on linguistic competence towards ?an increasing concern with linguistic performance and pragmatics? (Ortony, 1993). Representative of this shift is Lakoff and Johnson?s Metaphors We Live By. In this book the authors argue that our ideas are not only referred to linguistically through metaphors (defined by the authors as ?understanding and experiencing one kind of thing in terms of another?) but also actually conceptualized in metaphorical terms. The choice of a secondary subject in these metaphors is one that allows the speaker to conceptualize ?the nonphysical in terms of the physical ? that is, we conceptualize the less clearly delineated in terms of the more clearly delineated? the prime candidates for concepts that are understood directly are the simple spatial concepts, such as UP.? This claim is evident in physics, where we speak of high and low potentials and energy and conceptualize atomic forces as wells. As our choice of metaphor will reflect our conceptualization of the phenomena, our metaphorical choice may change depending on the context of the problem. Consider the following statements, ?Light consists of particles? which apparently contradicts ?light consists of waves,? but both are taken as true by physicists relative to which aspects of light are picked out by different experiments. (Lakoff and Johnson, 1980) There is enormous utility in being able to conceive of light in different ways ? to categorize light as a particle or as a wave. As Lakoff and Johnson state (1980), understanding our experiences in terms of objects and substances allows us to pick out parts of our experience and treat them as discrete entities or substances of a uniform kind. Once we can identify our experiences as entities or substances, we can refer to them, categorize them, group them, and quantify them ? and, by 20 this means, reason about them. When things are not clearly discrete or bounded, we still categorize them as such, e.g. mountains, street corners, hedges, etc. That is, there is a relationship between these categories and metaphorical language: our language, which Lakoff and Johnson demonstrate is profoundly metaphorical, allows us to categorize phenomena. Analogies in general, and metaphors in particular, are a topic of widespread interest and debate in linguistics at this time. Some of these debates will be further reviewed in later chapters. For a more complete review, see The Analogical Mind (Gentner, Holyoak and Kokinov, 2001). Analogies in science and science education ?I think it would also be practical to design a curriculum based on an inquiry into the use of metaphor. Unless I am sorely mistaken, metaphor is at present rarely approached in school except by English teachers during lessons in poetry. This strikes me as absurd, since I do not see how it is possible for a subject to be understood in the absence of any insight into the metaphors on which it is constructed. All subjects are based on powerful metaphors that direct and organize the way we will do our thinking. -Neil Postman, Conscientious Objections: Stirring up Trouble about Language, Technology, and Education A significant feature of the existing research on the role of analogies in instruction is that the focus has been on analogies drawn by the teacher and explained to the students. Research paradigms for constructing and testing models of analogical reasoning have similarly focused on the comprehension of analogies that have been created by the researcher. Very little work has looked at generated analogies. This paradigm is indicative of a tradition of science education in which the students are interpreting instruction from the teacher, and not discussing and debating their own views of science. As reforms in science education call for greater attention to student ideas and 21 student reasoning, the existing theories on analogy interpretation are of less use and there is a greater demand for understanding analogies as they are generated. Here I provide a brief overview on the research on the role of analogies in the classroom, the role of analogies in science, and the disconnect between what scientists do and what is attended to in classrooms. In a pioneering work on scientific analogies in instruction, Flowing Waters or Teeming Crowds: Mental Models of Electricity (Gentner and Gentner, 1983), students were given instruction in circuits using one of two different analogies: one visualized the flow of current as a crowd of electrons, one a flowing water-like substance. (Experts use both models to represent different features of current.) Tests given post-instruction were designed to test whether analogy is an important source of insight (the Generative Analogy hypothesis) by ?asking whether truly different inferences in a given target domain are engendered by different analogies? (Gentner and Gentner, 1983). The answers that students gave were overwhelmingly representative of the analogical model they had been taught. Clement?s work in physics education has focused extensively on analogical reasoning in the physics classroom, with attention primarily on explicit analogies generated by teachers and interpreted by the students. In Clement (1992), he describes ?bridging analogies.? These analogies are instantiated by the teacher and are used to motivate the students to see a likeness between two phenomena (say, the force provided by a spring supporting a book and a similar force from a table supporting a book) by providing intermediate analogies (a tight spring, a flexible board). The idea that a student will recognize ?A is like B? and ?B is like C? but not recognize that ?A is like C? without 22 explicit instruction supports a model of categorization in which ?family resemblance? to the category prototype defines the membership of the category. In this way, prior research on analogical reasoning can facilitate the link between analogies and categorization. In the following section I will provide an overview on research into categorization. More recent research on the role of analogies in physics continue in the paradigm of instruction by analogy: Taber, in When the Analogy Breaks Down: Modeling the Atom on the Solar System (2001), notes that: ?Analogy is one of the most potent tools in a teacher's repertoire and has been recognized as a common feature of quality science teaching.? He voices concerns regarding the utility of a solar-system model of the electron and the students? lack of knowledge regarding the solar system in drawing such an analogy. Mould (1998) is one of many instructional analogies that are frequently introduced in Physics Education. In this article, he suggests the use of an analogy to resolve the puzzle of the lost energy when two capacitors are joined together by comparing this scenario to the concept of water flowing between two tanks. Harrison and Treagust (1999) have explored the relationship between the analogies we tell our students and the models students construct from these analogies, arguing that ?students do not interpret scientific analogical models in the way we intended? and investigate potential factors in the consistency of analogy use in models of atoms. Notable exceptions to investigations on teacher-generated, didactic analogies include Duit, Roth, Komorek and Wilbers (2001) who ?studied analogy generation and 23 development and analogical reasoning with 25 German tenth graders in a physics class. Results show the advantages and disadvantages of using analogies in promoting conceptual change and as a teaching technique.? Their focus, however, was on the utility of analogy in conceptual change and not the generation of analogy as a goal in itself. And Yerrick, Doster, Nugent, Parke and Crawley (2003) who investigated the role of analogies in pre-service teachers? conversations and argue for analogy as part of preservice teachers? conceptual development. Turning to the role of analogy in science, and not just the science classroom, Dunbar (2000, 2001) has conducted research on ?in vivo analogies,? going to research groups and listening to the ways in which they use analogies and analogical reasoning in their work and discourse. Analogies, he finds, are ?frequent in science and in all aspects of human thinking.? They are ubiquitous and crucial to the ways experts reason about science. One goal of science education could be considered to develop habits and skills that scientists employ in scientific reasoning. The focus in the literature on analogies as a means of arriving at correct conceptual understanding ignores the import of developing analogical reasoning as a skill to be mastered in and of itself. As May, Hammer and Roy (2004) noted, ?inasmuch as expertise at inquiry supports? students and scientists developing conceptual understanding, young children?s development of understanding and abilities for analogical reasoning will serve them better than learning the content knowledge of an expert.? Summary of analogy research The main theme from this research that I will address is that the majority of research on analogies, and educational analogies in particular, has concerned how people 24 interpret analogies and not on the creation of analogies and its implications on mental models of concepts. If analogical reasoning is an important feature of scientific reasoning, then one goal of science education should entail fostering the use of analogies and developing students? abilities in this realm. As educational researchers, understanding analogical reasoning, what assertions analogies make, what they reveal about the mind, are of importance ? not because such findings allow us to better convey content, but because they inform us about a skill that is, in itself, one we should foster in our students. Categorization Overview Categorization is not a matter to be taken lightly. There is nothing more basic than categorization to our thought, perception, action, and speech, Every time we see something as a kind of thing, for example, a tree, we are categorizing. Whenever we reason about kinds of things ? chairs, nations, illnesses, emotions, any kind of thing at all ? we are employing categories. Whenever we intentionally perform any kind of action, say something as mundane as writing with a pencil, hammering with a hammer, or ironing clothes, we are using categories. -George Lakoff, from Women, Fire and Dangerous Things In 1987, George Lakoff published Women, Fire, and Dangerous Things: What Categories Reveal about the Mind. This work thoroughly summarizes the research on categorization up to that time and interprets the philosophical implications of these findings. Rosch, who tied together existing research on categorization and created an experimental paradigm for investigating categorization, began from the opposite end ? she received her undergraduate training in philosophy and brought this to bear on psychology. Her honors thesis was on Wittgenstein?s 1953 treatise, Philosophical 25 Investigations (Scharmer, 1999), a work that is credited with ?the first major crack in the classical theory [of categorization]? (Lakoff, p16). The classical view of categories held that there were rules of membership and if an item met these rules then it was a member of the category (or, there are properties that define a category and all members must share these properties). In this view categories, therefore, were seen as binary with no internal structure: an item either was or was not a member of that category, and the research paradigm for categorization was to define the rules or properties. Wittgenstein?s work addressed the fact that certain categories, such as ?game,? do not fit this classical description. There is no one property that all games share, but rather there are family resemblances between games, so that ?chess and Go both involve long term strategy? chess and poker both involve competition. Poker and old maid are both card games? (Lakoff, 1987 p. 16). Additionally, these categories had no fixed boundary ? they could be extended and redefined as new games are introduced, or as previous games shift their context. About this time, a similar recognition of inconsistencies in our conception of categories occurred in mathematics. Categorization and fuzzy sets In mathematics, the analog of a linguistic category is the set. In classical set theory an instance either belongs to a set or it does not; there is no middle ground. An item?s membership in a set is determined by whether or not it has the properties that define that set, called the class intension. For example, if the set is the class of all objects that are green, the intension of that set is the property green. This clean definition of the set allows for simple rules to be associated with them. The set of objects that are either green or square is the union of the sets of green objects and square objects. The set of all 26 things that are green and square is the intersection of the sets of green objects and square objects. However, a complication associated with set theory occurs at the border between the set and non-set. For an intension that splits the set of all objects in two, such as greenness, items will either belong to the set of green objects, or to the set of non-green objects, but there is an ambiguity for items that falls at this boundary between green and not-green. Applying this simple mathematical structure of sets to human-created categories does not work. There is logical inconsistency in assigning such items to both sets and to neither set. And the commonly accepted solution to this problem is the ?law of excluded middle,? which simply forbids there being an object that falls exactly at the border of set and not-set. Zadeh (1965) saw this solution as indicative of the fact that classical set theory does not capture the way in which we experience the world. Things come in gradations: some animals are birds, and some animals are mammals, while some, like the platypus, with its bill, webbed feet and fur, seem to fall somewhere in between. Statements are not always either true or false. The standard solution to the incompatibility of set-theory sets and human categories is to claim that mathematics, with its rigid structure and well-defined systems, does not apply to many real-world problems. Zadeh's solution was to allow for gradual sets and ?fuzzy logic.? The amendment he made to standard sets was to allow membership in a set to be a non-binary concept, and then extend the operations on ordinary sets to account for this allowance. If an element x has membership in set A with value v and in set B with a value w, then the operations on sets are adjusted in the following way: Intersection: The value of x in A?B is the minimum of v and w. Union: The value of x in A?B is the maximum of v and w. 27 Complement: The value of x in the complement of A is 1-v. This theory allows for a category of ?P and not P? ? for example, the category defined by ?an apple that is not an apple.? The crabapple and Adam?s apple are both judged to be members of this category. Zadeh?s fuzzy set theory reflected a change in the conception of categories that had been developing in anthropology. Rosch and prototype theory About the same time, anthropologists, influenced by the Whorfian hypothesis (1956), assumed that color categories were arbitrary and different languages could carve the color spectrum in different, arbitrary ways. However by the late 1960?s it was found that, though different languages do vary in the number and kinds of colors they name, there is regularity in color categories among different cultures (Berlin and Kay, 1969). Speakers of different languages that disagree on color category boundaries will agree on which colors were good examples of these categories. Rosch, who was conducting research on the Dani in New Guinea, began looking at their color categories. She depicts the prior research on categorization in this way: When psychologists did research on concept learning, they used artificial concepts and sets of artificial stimuli that were constructed so that they formed little micro-worlds in which those prevailing beliefs about the nature of categories were already built in. Then they?d do their learning experiments. But what they found out in terms of the nature of categories was already a foregone conclusion because that was what they had already built into it (Scharmer, 1999). Rosch argued that, because of the way the perceptual system works, certain areas in the color space are more salient than others, and that those salient colors are first noticed, most easily remembered, and become prototypes around which color categories form in cultures. The Dani had only two basic color terms, dark and light, making this culture 28 ideal for testing the hypothesis. By teaching them novel color categories, structured around natural and unnatural color schemes, Rosch found that the Dani remembered the hypothesized ?universal prototype? colors better than other colors, and it was much easier to learn categories structured around those colors than categories structured some other way. Further research extended this to shapes and other categories, and supported her thesis that categories form around and (or) are mentally represented by salient or information rich or highly imaginable stimuli which become prototypes for the category. Other items are judged in relation to these prototypes; that's the way they form gradients of category membership. There don't need to be any attributes which all category members have in common, no defining attributes, and category boundaries don't need to be definite (Scharmer, 1999). In the research that followed, Rosch (1975) showed that certain category members were judged to be better examples of the category than others. A robin is judged to be a better example of the set birds than a penguin, although, strictly speaking, both are birds. This psychological rendition of Zadeh?s fuzzy set theory established fuzzy logic as an important component of AI research. In addition, Rosch?s research established experimental paradigms for investigating categorization, attending to features such as the following (using the category ?bird? for illustration): ? Direct rating. (How birdlike is this?) ? Reaction time. (Show a picture and ask: Is this a bird?) ? Producing an example. (Draw a bird.) ? Asymmetry of similarity. (Are ducks like robins? Are robins like ducks?) ? Asymmetry of generalization. (Robins get the flu; do ducks? Ducks get the flu; do robins?) 29 In this paradigm, a prototype will receive a high rating, low reaction time, and resembles the example produced. From this research, properties of categories were determined. These are detailed in the following section. Properties of categories It was readily apparent that the structure of real categories, as researched by Rosch and others, was not consistent with the classical view. Categories, which in the classical view were devoid of any internal structure, were shown to possess both centrality gradience (the idea that some categories have members that, though clearly within the category boundaries, are more or less representative of the category) and membership gradience (the idea that some categories have degrees of membership, so that the distinction between member and non-member, the category boundary, is not clear). Members of many categories were related to one another in a ?family resemblance? manner, so that no one property is common among all members. The structure of categories leads to ?a basic psychological asymmetry: the less prototypical category member is conceived of as closer (i.e., more similar) to the more prototypical member than vice versa? (Shen, 1999). People will more readily compare a non- prototype to a prototype and will more likely generalize from the prototype to the non- prototype than vice versa (Rips, 1975). There is a primary level of categories, known as the basic level, that are ?primary with respect to the following factors: gestalt perception, image formation, motor movement, knowledge organization, ease of cognitive processing, and ease of linguistic expression? (Lakoff, 1980). The most central members of a category can function as metonyms for that category ? a property common to many languages. For example, American Sign Language has no sign for the category jewelry 30 and in ASL this category is referred to by listing the prototypical members (Newport and Bellugi, 1978 p 62); the Hopi call all trees ?cottonwood,? the name of the most common deciduous tree in their habitat (Trager, 1936-9); Shoshoni speakers refer to large birds in general as well as to eagles themselves as eagles (Hage and Miller, 1976). From this data, initial theories on categorization argued for interpreting category membership and structure as degree of similarity to the category prototype. However, further work showed that categories are not defined solely by family resemblance to a prototype, but have an intellectual and ecological basis. Barsalou?s (1983) studies of ?ad hoc? categories, categories that cannot be interpreted as fixed cognitive structures, such as ?foods not to eat when on a diet,? or ?things to do at a convention,? found that members of these categories retain the graded structure and typicality effects that Rosch found. However, these categories did not necessarily show a family resemblance to the prototype. Instead, Barsalou argues, these categories are goal-oriented; a chocolate cake has little resemblance to peanut brittle, but abstaining from these satisfies the goal of eating as few calories as possible. Similarly, research was beginning to reveal that similarity alone could not account for even the more typical, stable categories. For example, ?the claim that something is a dog does more than assert some degree of similarity to a prototype; it also appeals to our underlying intuitions and beliefs about the nature of animals. The effect of these beliefs is to make some similarities between objects decisive and others simply irrelevant? (Neisser, 1987 p3). The claim that similarity alone is an explanation, according to Goodman (1972), is ?a pretender, an imposter, a quack. [Similarity] has, indeed, its place and its uses, but is more often found where it does not belong, professing powers it does not possess.? In Murphy and 31 Medin?s (1985) paper, ?The Role of Theories in Conceptual Coherence? they argue against similarity arguments, claiming that Current ideas, maxims, and theories concerning the structure of concepts are insufficient to provide an account of conceptual coherence. All such accounts rely directly or indirectly on the notion of similarity, and we argue that the notion of similarity relationships is not sufficiently constraining to determine which concepts will be coherent or meaningful. These approaches are inadequate, in part, because they fail to represent intra- and inter-concept relations and more general world knowledge. We propose a different approach in which attention is focused on people?s theories about the world. The argument entails that categorization assumes a (folk) theory on the part of the person who is engaged in that particular cognitive process. This theory ?guides? him in selecting the relevant features and the relevant feature correlations; in other words, noticing features and feature correlations is not an ?objective? process based on similarity, but is instead theory-dependent.? (Shen, 1992) The effect of these findings is to make some similarities between objects decisive and others irrelevant. With these and other findings, Rosch eventually came to the conclusion that prototype effects, defined operationally by experiment, underdetermined mental representations. The effects constrained the possibilities for what representations might be, but there was no one-to-one correspondence between the effects and mental representations. The effects had ?sources,? but one could not determine the sources given the effects. (Lakoff p 43) An alternative to prototype theory is described below. Idealized cognitive models As a theory to explain the prototypes that Rosch first documented, Lakoff, in Women, Fire and Dangerous Things claims that ?prototype effects result from the nature of cognitive models, which can be viewed as ?theories? of some subject matter.? (p. 45) Lakoff terms these models ?idealized cognitive models,? or ICMs, and suggests that, to the degree to which the model does not represent reality, these ICMs will lead to 32 categorization and prototype effects. A classic example from linguistic research of categorization, prototype effects and gradience of membership in a category is the term bachelor (Fillmore, 1982). While most people will define a bachelor as an unmarried adult male, certain unmarried adult males are not representative members of the category of bachelors. Lakoff (1987) argues that bachelor is defined with respect to an ICM in which there is a human society with (typically monogamous) marriage, and a typical marriageable age. The ideal model says nothing about the existence of priests, ?long-term unmarried couplings,? homosexuality, Moslems who are permitted four wives and have only three, etc. With respect to this ICM, a bachelor is simply an unmarried adult man. This idealized model, however, does not fit the world very precisely. It is oversimplified in its background assumptions. The person referred to deviates from prototypical bachelorhood if either the ICM fails to fit the world perfectly or the person referred to deviates from being an unmarried adult male. Under this account bachelor is not a graded category. It is an all-or-none concept relative to the appropriate ICM. The ICM characterizes representative bachelors. One kind of gradience arises from the degree to which to ungraded ICM fits our knowledge (or assumptions) about the world. (Lakoff, 1987) ICM?s can closely match the world, in which case the categories that you developed to create this ICM are robust categories with little gradience. The idea of the ICM has been further parsed and is perhaps best represented by schema theory. Schemas are short ?scripts? or stories that we have about the world and the way it works: event schemas that are abstracted from our experience of certain events, image schemas that provide structure for conceptualizations ? ?schemas of intermediate abstractions [between mental images in abstract propositions] that are readily imagined? (Palmer, 1996 p. 66) ? and proposition schemas: abstractions that act as models of thought and behavior and specify 33 ?concepts and the relations which hold among them.? (Quinn, 1987) It is only within a particular schema that a category is meaningful, and these categories become les meaningful and exhibit a graded structure to the degree that the schema in which they are defined does not apply. A claim of analogies as assertions of categorization then entails analogies as instantiations of particular schemas. Metonymy, cognitive models and phenomenological-primitives Phenomenological primitives (p-prims) (diSessa 1993) were developed to address the ?preconceptions? of students in problem solving in physics. They are ?the intuitive equivalent of physics laws; they may explain other phenomena, but are not themselves explained with the knowledge system.? As defined by diSessa, p-prims are ?cued to an active state on the basis of perceived configurations, which are themselves previously activated knowledge structures.? In this way p-prims are elements within larger models. P-prims ?often originate as minimal abstractions of common phenomena,? and are ?nearly minimal memory elements, evoked as a whole.? By way of example, consider one class of p-prims: the ?constraint cluster.? This class includes bouncing, supporting, guiding, clamping, and carrying. These p-prims are not fundamental for a physicist (all can be explained in terms of forces) but are often elicited in conversations with students as explanations for physical behavior. The p-prims have a ?schematization? such as, for the ?supporting? p-prim, ??strong? or stable underlying object keeps overlaying and touching object in place.? (diSessa, 1993 p. 216) That a p-prim has a full schematization but is often represented only partially by a particularly salient feature of the schema (e.g., ?supporting? as an explanation entails two objects, one of which is strong or stable and underlies another object which touches it) is 34 indicative of the schematization of a p-prim being an idealized cognitive model. This single salient feature of the schema is what Lakoff refers to as a metonym for the idealized cognitive model. Lakoff presents the following example to explain metonymy is the context of ICMs (Lakoff, 1987): A linguist who does fieldwork on Ojibwa, a Native American language... asked speakers of Ojibwa who had come to a party how they got there. He got answers like the following (translated into English): -I started to come. -I stepped into a canoe. -I got into a car. He figured out what was going on when he read Schank and Abelson's Scripts, Plans, Goals, and Understanding (1977). Going somewhere in a vehicle involves a structured scenario (or, in our terms, and ICM)... In Ojibwa it is conventional to use the embarcation point of an ICM. That is to say, the embarcation point is a metonym for the entire structured scenario, or ICM. English, too, uses a point of the journey to refer to the whole. Typical English responses to the question of ?How did you get here?? may be: ?I have a car,? or ?I biked.? Neither comment conveys the entire journey, but chooses one part to represent the whole. This is only possible because we have a model for the journey, and one part can, metonymically, elicit the whole. In the same way, phenomenological primitives as explanations for physical phenomena are only possible because of a larger schema. The claim I will make, that the p-prim and schema precedes or is in some way more fundamental than the analogy itself, is echoed in diSessa?s studies involving the ?Montessori bell conundrum.? In this problem, students are presented with bells made of the same material, same length, same height, but varying widths. Almost without exception students predict (erroneously) that the thicker bells will have a lower pitch. DiSessa reports: 35 Although most subjects were ready with analogies ? church bells compared with jingle bells, xylophones, musical instruments of various sizes ? I was struck that some initially could not produce any example of the phenomenon they identified to be at the root of the situation. This, along with the rapidity and expressed certainty of responses, heightened my confidence that a p-prim (or several) was at stake rather than analogy. In following chapters, I will present data that argue that generated analogies stem from a set of schemas or p-prims. Summary of categorization research The main points I will be taking from categorization research are the established properties of categories (including graded structure, asymmetry of generalization, prototypes, family resemblance, and metonymy), that categories can be considered ad hoc constructions (and still retain the characteristics of a category), that theories, expectations and goals underlie our construction of some categories, and that graded structure in categories is a reflection on the degree to which these theories match the ?real? world. Analogies as Categorization Metaphors as category-inclusion statements Consider the following statements, one typically considered categorization and the second analogy: 1. This ball bearing is a mass. 2. In circuit with an inductor, capacitor and resistor, the inductor is like a mass. The first is a statement that the ball bearing is a member of the category ?mass.? The second, however, is not a statement that the inductor is a member of that category, but, I argue, by drawing the analogy we are suggesting that the inductor and that the members 36 of the ?mass? category share some categorical grouping in common. One could characterize that category ?things which slow the rate of change? (this characterization is referred to as a ?ground? in a metaphorical comparison). This category is rarely referred to and therefore is not a stable category with its own name, but more of the ad hoc type category that Barsalou (1983) introduced ? a spontaneously constructed category that is structured by theories or goals. Glucksberg and Keyser (1990) were the first to identify this relationship and have argued for interpreting metaphorical assertions as categorical assertions, claiming that When people use metaphors, they are saying exactly what they mean. When, for example, someone says that ?Sam is a pig,? that is precisely what is meant; that the person designated by the name ?Sam? is a member of the superordinate category referred to by the word ?pig.? Glucksberg and Keyser argue that the choice of the secondary subject in a metaphor (pig in ?Sam is a pig?) reflects a tendency of languages to have names for basic level objects but not for superordinate categories. Such examples can be seen in the English language, as in the aphorisms ?Boys will be boys? or ?Cambodia has become Vietnam?s Vietnam? (or, as mentioned recently in the 2004 election, ?Florida does not want to be the next Florida). These expressions use a ?single referring expression? in two distinct ways, to allude to the entity itself and to refer to the category? that this entity has come to exemplify? (Glucksberg and Keyser, 1990 p. 411). (For example, ?eagle? in Shoshoni and ?cottonwood? in Hopi, as mentioned in a previous section.) When the base of an analogy (termed the vehicle in the context of metaphor) is used as both an exemplar and as an ad hoc name for a category, Glucksberg et al. (1997) call this linguistic move ?dual reference.? As an example of dual reference, 37 the phrase ?a responsibility is a shackle? can be used to refer to the concrete, physical device that is made of metal, often has chains, can be locked around someone?s arms and legs, and so forth, and it can also be sued to refer to the abstract, general category of constraining entities. We refer to such abstract, general concepts as attributive categories. (Glucksberg et al, 1997 p. 334) The authors claim that ?nouns can be used to make dual reference whenever a superordinate category has not been lexicalized and a category exemplar is available that is prototypical of that category.? Glucksberg and Keysar continue with the assertion that metaphor is not a literal comparison, and must be considered property attributions that extend or create categories. As an example, they contrast the literal comparison with the metaphorical: ?Copper is like tin?? cannot be paraphrased as category assertions and still make sense, for example, ? ?Copper is tin.? Thus the paradox: Two unlike things compared can be paraphrased as a categorical assertion, whereas two like things compared cannot. This paradox may hold the key to a fundamental difference between literal and metaphoric comparisons. We argue that metaphors are not understood as comparisons, but rather as property attributions that either extend old categories or create new ones. I hold that the difference in these statements is a result of what Roger Brown originally described: ?Metaphor differs from other superordinate-subordinate relations in that the superordinate is not given a name of its own. Instead, the name of one subordinate is extended to the other? (Brown, 1958). ?Tin? is not a name for the category of which they are members (owing to the fact that this category has a name and that tin is not a prototypical member) and ?jail? is (because this category, as it is less stable, has no name and is referred to by its most prototypical member). Furthermore, placing tin and copper in the same category is expected and does not violate any previously held ontology or necessitate the construction of a new, ad hoc category, unlike placing jobs and jails into the same category. And, as Barsalou (1983) has shown, ad hoc categories have the same 38 structure and properties as traditional categories. The difference, then, between a metaphorical comparison and a literal one may have cognitive importance in terms of stability of the category and conceptual coherence, but not in terms of the conceptual structure. Shen?s (1992) Metaphor and Categories makes similar claims as Glucksberg and Keysar. He argues that ?in interpreting a metaphorical comparison, an ad hoc category is constructed so that the two metaphorical terms are conceived of as its members,? and that the secondary term in a metaphorical statement is typically ?a prototypical member of that category.? Shen, too, makes a distinction between literal comparisons and metaphorical comparisons, claiming that a literal comparison is indicative of a ?common? category, while ad hoc categories are represented by metaphorical comparisons. Traditionally, metaphors have been interpreted as statements of similitude and not categorization because of the assumption that words (such as ?pig? when claim that the person ?Sam is a pig?) refer to specific taxonomy. Studies on how our minds perceive of words and how these perceptions are related to taxonomic definitions versus metaphorical relationships are detailed in the following section. Idealized cognitive models and lexical networks Eve Sweetser?s 1984 tests of the definition of ?lie? (as in ?to tell a lie?). She points out that, while most people define a ?lie? as ?a false statement,? in practice: A consistent pattern was found: falsity of belief is the most important element of the prototype of lie, intended deception the next most important element, and factual falsity is the least important. These findings are consistent with the idea that humans conceive of the world using idealized cognitive models and that the imperfection of these models results in a graded 39 structure of categories. In the ?lie? example the ICM being employed is a model of communication, as studied by Grice (1975). Grice removed the study of language from its Chomskian position of mathematical clarity and tied it to the study of communication arguing that, in order to understand the way language works, one must understand expectations that exist in communication. These expectations (the idealized cognitive model of communication) entail clarity, truth, information, and relevance on behalf of the speaker and influence our expectations for the definitions of words. If words, such as ?lie? are not used in a manner consistent with the definition one would find in a dictionary, how are words represented in the mind? Recent psycholinguistic theory has suggested that the mental lexicon, instead of being organized in a dictionary-style, is far more like a thesaurus. That is to say, the way our minds perceive of words is not so much as obeying rigid definitions with propositional structure, but rather the meaning of one word is tied to a network of related words ? words that have appeared in similar contexts, words that have appeared in context with that word, and words that have related meanings. Computationally generated lexical networks have been developed to represent the lexical network of the English language as expressed in dictionaries (one example is the well-known Wordnet (Fellbaum, 1998)). These thesaurus-like structures link words in definitions into a network using various algorithms. Gaume et al. (2002), building on categorization research that they summarize as establishing the ?conceptual flexibility? as opposed to ?rigid and discontinuous categories,? argue that words themselves constitute categories and contend that these lexical networks weave a ?mental lexicon distributed around metaphoric poles.? In this regard, dictionary definitions of terms such as ?lie,? ?pig,? and ?boys,? especially in the 40 contexts noted above, can be expected to fall short of the full meaning of these terms as used in regular language. When these terms are expressed in a lexical-network sense, they can be viewed as representing categories of characteristics or qualities, rendering the metaphorical statements, such as ?he?s a pig? and ?boys will be boys,? as assertions of class-inclusion as Glucksberg and Keysar (1992) have argued. Reconciling categorization and structure-mapping views of analogies To address the ideas raised by Glucksberg and Keysar and reconcile these with Gentner?s structure-mapping theory of analogy, Bowdle and Gentner describe a ?path in figurative language comprehension? that claims that there is a shift in the method of comparison in figurative language. Novel metaphors, they claim, are interpreted via a structure-mapping mechanism, while conventionalized metaphors ? words that have an original meaning that is different from an often-used meaning (e.g., ?roadblock? or ?goldmine?) ? are interpreted as categorization. The issue of comprehension of metaphor is not at the heart of this thesis: what someone means when they make a novel analogical statement has to do with the creation of an analogy. It is reasonable, however, to expect that understanding a conventional metaphor might be a similar process to creating your own metaphor: in both cases the categorical commonalities (the ground of the category) is known, while interpreting a novel metaphor would require a ?search? of possible meanings of the secondary subject that are being implied. Conclusion Words, such as ?lie? and ?pig,? have definitions that exist in a dictionary ? stable definitions that people will readily agree on as sensible. These definitions possess a rigid propositional structure, so that ?pig? is thought to mean ?pink animal with a snout? and 41 ?lie? is defined as ?an untrue statement.? But these definitions are only valid when you accept a certain model about the ways in which we communicate. When you take into account that communication is not so straightforward as our idealized cognitive models of language assume, pinning down the exact description or definition of a word, such as ?lie? or ?pig,? is a much more difficult endeavor ? more context dependent and slippery. Lexical maps, which link related terms into a network, more closely approximate the lexical structure (or dictionary) of our minds. Accepting this about language has implications for the interpretation of analogical statements: traditionally, an analogical statement is not literal because the base of the analogy is not intended to be interpreted literally. Instead, I argue that analogical statements are assertions of categorization, and the difference between analogy and traditional categorization is that analogies violate an expected ontology and may even necessitate the construction of a new, ad hoc category. To say that ?Sam is a pig? demands that you consider the nodes in the ?pig? lexical network that could possibly relate to Sam (including muddy, slovenly, lazy, messy) ? just as when one says ?I eat pig? (typically viewed as a non-metaphorical statement, but one which calls up the pork chop, ham, and sausage aspects of the pig lexical network). The difference lies in that ?pig? is defined in the cognitive model that allows for this animal as distinct from others and ?Sam is a pig? requires you to ?turn off? some parts of the network. In the following chapters I will argue that generated analogies in science are statements of category-inclusion that violate the expected categorization of the target. When a student asserts that a cup of water is like a cat in a basket, she is constructing an ad hoc category, this category is intimately tied to a theory and cognitive model, is 42 derivative of this model, and that the secondary item in the analogy is a prototype of this ad hoc category. Furthermore, these categories and their structure are indicative of an underlying idealized cognitive model ? ones that are often metonymized by phenomenological primitives. This interpretation of analogies is responsive to findings from cognitive science, linguistics and education that argue for a manifold ontology of mind. 43 Chapter 3: Origins of the Study & Methodological Considerations Origins of the Study The following passages are taken from a ?Science Talk? (Gallas, 1995) in 5 th grade classroom in rural Maryland. It is early November and the science resource teacher, Bruce Booher, has come to lead a discussion. The students have worked with Mr. Booher in the past and this format of science instruction is not unfamiliar to them. The question that he has chosen comes from an experiment suggested on a NASA website regarding zero gravity. The students are posed the following question (NASA, 1999): a cup full of water is inverted on a cookie tray and the tray is rapidly pulled out from underneath the cup (see Fig. 3.1). What happens to the cup-water system? The students will later observe that the water does not leave the cup as it falls to the ground ? the cup falls at the same rate as the water and the water will only spill out once it reaches the ground. Most students, however, believe the water will ?go everywhere,? ?spill,? or ?splash? as the tray is removed and report as much. Their answers do not give any rationale or mechanism by which this will happen. However, one student predicted the correct outcome and explained her prediction with a spontaneous analogy (transcript 2, lines 8 ? 36). 44 Fig. 3.1: The Experiment: A tray pulled out from under a cup Teacher: ?let?s see what some? I see a lot of other hands up. Um, Miranda? Miranda: I predict that when it falls off it?s going to stay in the cup until it gets down to the floor and then it?ll splash. Teacher: So you have a prediction that when I slide it off of the tray the water is going to stay in the cup. Now that?s very different from what they?re saying. Miranda: ?Cause at home when I have like something in a basket and when I go like that real quick [student swings arm around, miming that the basket is swung overhead and quickly pulled down] it stays in. So when ? and when I pull it down like this [motions pulling basket straight down] like upside down on the way down it stays in until it gets to the bottom and then it comes out. Teacher: So you?re using now this example of something that you?ve done at home where you have an object in a bucket ? or a basket, you said ? and what do you do? You ? Miranda: I go like this and then I pull it down and it stays at the top until I stop and then it comes out. [Motions swinging overhead and pulling down, lifts hands to show that it stays at the top of the basket.] Teacher: So you swing this ? what?s in the basket? What object is in the basket? Miranda: Sometimes I put like, like a little toy cat that I?m playing roller-coaster with and put it in there and I pull it down and it stays in the back [motions that the cat is up at the top] until I stop and then it comes out. Wholly aside from the fact that this analogy leads to the correct prediction, this analogy shows the beginnings of deep scientific reasoning. As I will show in later chapters, 45 mechanistic analogies to phenomena with which you have experience are ubiquitous in the scientific literature. Furthermore, once this analogy is brought up the tone of the conversation changed; student hands shot up, and mechanistic reasoning and scientific explanations were brought up. In an attempt to understand this moment ? what, exactly, was the significance of Miranda?s analogy, what are the assertions that it makes, the cognitive work that it does, why it was brought up, how it was negotiated, how the other students react to and negotiate the analogy ? there are few models of analogical reasoning to turn to, fewer still on spontaneously-generated analogies; studies on analogical reasoning suggest that comments like Miranda?s should be rare, are indicative of expertise, and more likely with prompting by the teacher. Furthermore, most models of analogy are stem from variable process/regularity approaches to explanation and not causal or meaning-based models. In this chapter I will outline previous studies on analogical reasoning, their philosophical assumptions, the strengths of these approaches and their shortcomings. I then outline the tradition in which my own study is based and explain the theoretical nature of this dissertation and its methodology. History of Research on Analogies Past research Owing, perhaps, to the behaviorist tradition in psychology, the success of experimental methods in more objective sciences, or stemming from the more recent analogy of the mind to a computer with its fixed rules and stability, studies in learning, particularly in cognitive science, have tended to focus on quantitative studies in laboratory settings. The history of analogical reasoning is no exception. 46 The most well known example of experiments on analogical reasoning is that by Gick and Holyoak (1980 p 307-308). In their study, participants were presented with Duncker?s (1945) ?radiation problem.? The problem begins with an anecdote: A general wishes to capture a fortress located in the center of a country. There are many roads radiating outward from the fortress. All have been mined so that while small groups of men can pass over the roads safely, a large force will detonate the mines. A full-scale direct attack is therefore impossible. The general?s solution is to divide his army into small groups, send each group to the head of a different road, and have the groups converge simultaneously on the fortress. The students were told to memorize the above passage and then asked to solve the following problem: You are a doctor faced with a patient who has a malignant tumor in his stomach. It is impossible to operate on the patient, but unless the tumor is destroyed the patient will die. There is a kind of ray that may be used to destroy the tumor. If the rays reach the tumor all at once and with sufficiently high intensity, the tumor will be destroyed, but surrounding tissue may be damaged as well. At lower intensities the rays are harmless to healthy tissue, but they will not affect the tumor either. What type of procedure might be used to destroy the tumor with the rays, and at the same time avoid destroying the healthy tissue? Few students were able to solve the problem without explicit instruction to use the story that they had memorized. Once prompted, over 90% of students could solve the problem correctly using the convergence principles from the fortress story. This study has been widely cited as evidence that students find analogical reasoning difficult and that transfer is a rare phenomenon. Furthermore, it established a paradigm for investigating analogical reasoning: present participants in the study with two analogically similar scenarios and see if they notice/draw the intended analogy. This methodology has been reiterated in future studies of analogical reasoning with similar results. In one study, Gentner, Ratterman and Forbus (1993) gave subjects a 47 series of stories to read and followed up one week later with another set of stories. Some stories were structurally similar to stories in the first set, while others shared superficial features ? about a similar topic or involving a similar kind of animal, say. The subjects were then asked which of the original stories these reminded them of and they chose the stories that shared superficial features. Again, the authors argued that subjects are not drawing analogies between deep structural similarities. However, Markman and Gentner (1993) report a study in which they ask participants to look at two pictures and find the ?same thing? in the two photos; they found in this case that items that occupied similar roles were more often chosen as similar than superficially similar items. Novick (1988) reports a similar finding in the context of mathematics to Markman and Gentner?s findings ? that analogies based on structure are possible ? but that such analogies are more likely if the participant has sufficient expertise in the subject. (Which echoes findings by Chi, Feltovich and Glaser (1981) in which expert physicists tend to group problems based on principles rather than surface similarities, while novice physics students grouped the same problems using superficial characteristics.) These studies, and those with similar methodologies, are powerful for their clear findings; they tell us quite definitively that in these scenarios, under these circumstances, subjects behave in this way. Indeed, this methodology, in the tradition of scientific based reasoning (SBR), is hailed in a National Research Council report, Scientific Research in Education (2002). 48 Limitations of past methodology What, then, are the limitations of such research for understanding spontaneously generated analogies in science? While it has its strengths of clear and exact findings, I claim that such focused, constrained, laboratory-based studies (1) establish too strong constraints on what counts as analogical reasoning, (2) strip analogies of the crucial context in which they are constructed, and (3) fail to capture a causal explanation of analogical reasoning. I detail these below, and then introduce a qualitative alternative to such studies of analogical reasoning. I conclude by introducing the methodology employed in this thesis. (1) Constraints Consider the story by Hammer et al.?s (Hammer, Elby, Scherr, Redish, 2004) of a student discussing the size of mirror necessary to see your entire body in it. This student, Sherry, determines that you need a mirror the same size as your body, because your whole body has to be able to fit in it. Other students in her group used ideas about reflection to argue that the mirror would need to be half that size, but Sherry defended her reasoning. The next week she told her group about a discovery at home: She owns a mirror roughly half her height, and it shows a reflection of her whole body. She had known the answer to the question all along ? she saw it every day. In their article, this anecdote is brought up to call into question the notion of transfer. I mention it here to suggest that even when students are not drawing appropriate analogies ? such as between the tumor and the fortress in Gick and Holyoak?s? they may be drawing deep analogies nonetheless. Sherry, the authors suggest, may have been drawing a tacit analogy to doors or paintings instead of the more correct analogy to windows. The participants in Gick and Holyoak?s study may be drawing analogies to bullets, sound in 49 rooms, or light coming in through windows (it certainly seems just as bright by the window as it does in the center of the room). Gick and Holyoak may claim that participants did not draw the desired analogy between the tumor and the fortress, but they may not claim that students did not draw an analogy. (2) Lack of context Similarly, Gentner, Ratterman and Forbus?s findings demonstrate that similarity ? or, more accurately, reminding ? is based initially on superficial characteristics when done in the context of a laboratory, but these stories lacked context and immediacy. Recently I was explaining to a friend the story of Moneyball (Lewis, 2003), in which a baseball manager ignores baseball?s cultural wisdom of choosing draft picks in favor of statistical analysis by Harvard graduates. My friend replied that he was reading a similar story about Bj?rk in the New Yorker (Ross, 2004) and commented that this seems to be a trend in nonfiction writing ? to tell the story of someone who has an entirely different perspective on the ?system? and revolutionizes it despite naysayers to great success. In this real-life context, comparing Moneyball to superficially similar stories (say, ?Casey at the Bat,? Thayer, 1997) would have been unnatural and bizarre, while comparing Moneyball to Bj?rk was creative and insightful, but also natural and a logical conversational step. In a laboratory setting, with few stories to choose from and no reason for the stories to be told in the first place, our cognitive behavior can be unnatural and bizarre. It is important, then, to pair our laboratory based studies of cognition with studies ?in the wild.? 50 Why has it required conscious and deliberate effort to integrate context into studies of learning and cognition? As Lemke explains: We blame the early Moderns of Rene Descartes? 17th-century Europe for cleaving Mind from Body and Society from Nature (e.g. Shapin & Schaffer 1985, Latour 1993). From them we inherited a chain ? cognition in the mind, mind ?in? a material brain, brain in a mindless body, body in a natural environment separate from society, society made up of persons not bodies, persons defined by cultures, cultures created by minds ? a chain that binds us still and runs us ?round and ?round in ever smaller circles. We rebel, we transgress. We want the freedom to construct a materiality of mind, an intelligence of the body. We want meaning to arise from material processes and Culture to be once again a part of Nature. We want to re-situate cognition in a larger meaning-making system of which our bodies and brains are only one part. We are willing to pay the price, to abdicate our Lordship over Creation, to become partners rather than over-seers. Creation, after all, has been getting pretty unruly anyway. That is, Cartesian dualism, which proved so powerful for the traditionally ?hard? sciences, has left its legacy in the behavioral sciences which may not be appropriate: it places meaning outside the scope of scientific research, separating questions of meaning ? which are intimately tied to context ? from questions of science. Since the initial studies of analogy reported above, which occurred in the early 1980?s, researchers in cognitive science and education have become increasingly concerned with the assumptions noted by Lemke that laboratory-based studies make on the nature of cognition. Gibson (1979), studying perception, emphasized the need to study vision in terms of people behaving in the real world performing meaningful tasks rather than subjects responding to the artificial and acontextual conditions of the laboratory. Lave, continuing this paradigm into the learning sciences, performed a series of classic studies (Lave 1988, Lave & Wenger 1991) observing people ? tailors, midwives, and dieters ? in real-world settings as they engaged in problem-solving. She 51 found that their strategies in these immediate, concrete, specific, and meaning-rich situations differed from the disconnected problems of school or the tasks posed in a psychology lab. From these studies, she coined the term ?situated cognition? to describe cognition as a ?nexus of relations between the mind at work and the world in which it works? (Lave, 1988 p. 1), and any claims about how cognition ?works? must take into account the world in which it is working. (3) Causal explanation A final concern for laboratory-based studies of analogical reasoning comes from Maxwell?s (2004) concerns about the types of claims these studies can make about causation. That is to say, he finds fault with what causation means when arrived at from a laboratory-based, quantitative study. Concerned with the emphasis on scientific based research (SBR) in the National Research Council?s Scientific Research in Education (2002) report, Maxwell traces the philosophical traditions of SBR and argues that it assumes a ?regularity? view of causation. The regularity view is based on an analysis of the contribution of differences in values of particular variables to differences in other variables. The comparison of conditions or groups in which the presumed causal factor takes different values, while other factors are held constant or statistically controlled, is central to this approach to causation. He further argues that ?the central manifestation of the regularity view in the NRC (2002) report is its presentation of causality as primarily pertaining to whether x caused y, rather than how it did so? (Maxwell, 2004 pp. 125?129). This claim is certainly true in the studies of analogical reasoning reported above: these experiments cite circumstances under which deep analogies are or are not drawn (such as: expertise is important, deep 52 analogies are rare in the context of comparing two items), but make no claims as to why analogies are drawn, what cognitive work these analogies do, the purpose that analogies serve and why students fail to draw analogies in certain situations. These three concerns ? the constraints that laboratory based research places on analogical reasoning, the claims of situated cognition that demand ecologically valid research, and failure of variance theory research to arrive at meaning or mechanism ? have motivated researchers to perform qualitative studies of analogical reasoning. These studies are discussed below. Recent approaches to the study of analogical reasoning Noting the criticisms of laboratory-based research on cognitive processes that claim ?what we know of cognition is based on arbitrary tasks bearing little relationship to the cognitive processes that occur in naturalistic settings? (Dunbar and Blanchette, p 334), and in the tradition of situated cognition research methodology, Kevin Dunbar and Isabelle Blanchette investigated the use of analogy in natural contexts. They explain, ?we wanted to discover what similarities people note and under what circumstances their reasoning is based on superficial or structural similarities.? They began by video- and audio-taping molecular biology and immunology labs and analyzing the types and frequency of analogy generation in these conversations. A similar approach was taken in a study of generated analogies in 6 th grade mathematics classrooms. A recent article by Richland, Holyoak and Stigler (2004) reports an in-vivo study of analogies with their research in eighth grade mathematics 53 classrooms. As with Dunbar?s methodology, Richland et al. construct a coding scheme and deep analysis of the kinds of analogies that are generated in the classroom. The analyses performed on the data from these studies, though situated in a naturalistic context and with strong qualitative components, also continue a quantitative paradigm. These and other studies (for example, Pittman, 1999 and VanLehn, 1998) look at the kinds of analogies, the frequency of these analogies, rely on a large corpus of data to draw statistical claims about what happened ? again ?primarily pertaining to whether x caused y, rather than how it did so? (Maxwell 2004) or, perhaps more accurately in these cases, if x occurred and not why. To get at the meaning behind analogical reasoning ? that is, what are the assertions that analogies make, what cognitive work do they do, how might the mind be organized to allow for this ? I rely not on statistical analyses of data or rigorous coding of transcripts (which, of course, are invaluable tools of the educational researcher and a crucial component of many important methodologies), but instead a variety of approaches (primarily phenomenology and case study) and on the philosophy of causality behind process theory. An alternative to the regularity view (which Maxwell notes as characteristic of variance theory) is that of ?process theory? (Maxwell, 2004): Process theory? deals with events and the processes that connect them; it is based on an analysis of the causal processes by which some events influence others. It is fundamentally different from variance theory as a way of thinking about scientific explanation? (p. 5) A realist, process-oriented approach to explanation is compatible with, and facilitates, the key strengths of qualitative research. In particular, it recognizes the reality and importance of meaning, as well as of physical and behavioral phenomena, as having explanatory significance, and the essentially interpretive nature of our understanding of the former. It also recognizes the explanatory importance of the context of the phenomena studied, and does so in a way that 54 does not simply reduce this context to a set of ?extraneous variables.? It relies fundamentally on an understanding of the processes by which an event or situation occurs, rather than simply a comparison of situations involving the presence and absence of the presumed cause. Finally, it legitimates a concern with understanding particular situations and events, rather than addressing only general patterns. (p. 8) Maxwell then argues that qualitative research methods, because of their strengths at ?identifying causality in particular cases, the importance of context as integral to causal processes, and the role of meaning and interpretive understanding in causal explanation? are a crucial element in education research. It is in this tradition and due to these concerns that I choose to approach understanding student-generated analogies as they occur in classroom discussions. Methodology This thesis is a theoretical account of generated analogies in science, which began with an insight into Miranda?s generated analogy above; namely that the thing she seems to be making an assertion of categorization rather than a direct one-to-one mapping of this cup to that experience of twirling her basket. Following this insight, I developed an account of generated analogies as assertions of categorization using the events in this classroom research from categorization. This account was then compared with generated analogies in other contexts: different classrooms of various ages, historical accounts of analogy use in science, research group meetings and informal conversations. In these analyses, I compared my story of categorization to the existing accounts of analogy (primarily structure mapping), and I will argue that a categorization perspective is more 55 successful and generative than the others. Further implications of this perspective may then be tested in a more quantitative methodology. A note on the data None of the data presented in this thesis was collected for the purpose of studying analogies in science. While collecting data for a project on student inquiry in physical science, and knowing that I was interested in studying analogies in science (because of my own propensity for them), Miranda?s particularly powerful student-generated analogy struck me. At the same time, I was reading a book by Lakoff (1987) ? Women, Fire and Dangerous Things: What Categories Reveal About the Mind. With this one example of student-generated analogies and this one perspective on cognition, I began to develop a rough theoretical perspective for understanding student-generated analogies in science as assertions of categorization around this first analogy. I then turned to a corpus of data from student inquiry into physical science, research group meetings and classrooms to check against my account of analogical reasoning. The case study methodology Such a study is indicative of the case study tradition. The case study primarily addresses the how and the why research questions ? in my case, why analogies are generated, how they help students and the cognitive work that they do. The case study aims to provide a detailed description and analysis of the observed case. It acknowledges the importance of studying the phenomenon as a whole and does not consist of a linear model of inquiry, noting that ?there are complex relationships within phenomena, [and] taking them apart may result in losing some of their important aspects.? Additionally, the 56 ?case study is also naturalistic in the sense that it studies cases in their physical context, in which the researcher is also interested? the researcher has limited or in some cases no control over the case of study. Case study method also requires the study of a contemporary phenomenon or situation within its real life context? (Louca, 2004, p. 35). Furthermore it is the evaluation of a single case that Maxwell (2004) and Davidson (1967) argue may be a more powerful method for arriving at causality than the variant theory approaches. Davidson notes that we ?can infer cause in single experiments . . . [and that] providing them with conceptual help in doing so is a virtue, not a vice; failing to do so is a major flaw in a theory of cause-probing methods? (Davidson, 1967, p. 465). One key component of the case study, indeed of all qualitative research, is triangulation of information in which ?researchers make use of multiple and different sources, methods, investigators and theories to provide corroborating evidence. Typically this process involves corroborating evidence from different sources to shed light on a theme or perspective? (Creswell p 202). As I continued taping student conversations in physical science, which were replete with spontaneously generated analogies, I had further data to bring into and try out against my theoretical framework. This data primarily comes from elementary school classrooms throughout Maryland, ranging from second through sixth grade. The teachers in this study were part of the project Case Studies in Elementary Science and are particularly skilled at listening and attending to student ideas in science, which was significant in providing me with student- generated analogies. In addition, I used data from studies on high school and 57 undergraduate physics students ? data initially acquired for other research purposes ? along with tapes from research group meetings and faculty conversations. And finally, the framework was compared to analogies by scientists, as reported in studies from the history and philosophy of science, comparative literature and popular non-fiction. The analysis began with a phenomenological analysis, which will be explained in the following chapter and then a more ontological, causal analysis, which I will describe in Chapter 5. Summary This is a theoretical dissertation, one that argues for a particular perspective on student-generated analogies and the ontology of mind. As such, quantitative methods ? even those that are typically used in more qualitative research (coding, for example) ? are not employed here. That is not to say that these are not relevant to a framework of spontaneously-generated analogies. However, as Maxwell (2004) argues, I would argue that strictly experimental designs, with no qualitative components, are a comparatively powerful method for understanding only when three conditions obtain. First, there should be a well-developed theory that informs the intervention and research design and allows interpretation of the experimental results (Bernard, 2000, pp. 55?56)? Second, the causal process investigated should be manipulable, fairly straightforward and simple? Third, the situation should not be conducive to the direct investigation of causal processes. This thesis aims to begin with the first of these criteria by understanding the why of student-generated analogies, providing a framework of categorization and consistent with a manifold ontology of mind. Once established, the ability to manipulate the causal processes and whether or not these may be investigated directly may then be asked. 58 Chapter 4: Phenomenological Coherence Introduction The central thesis of this dissertation is that student generated analogies in science can best be interpreted as assertions of categorization. This description of analogy began with an analysis of a single classroom, first introduced in the previous chapter. In this chapter, I will highlight particular phenomenological aspects of this and other analogies and the negotiation of these analogies. I will explore the consistency of these aspects with a categorization framework. Alternative theories of analogical reasoning will be contrasted with a categorization description. In following chapter, I will address the implications that these phenomenological properties have on cognitive structure and how a theory of cognitive structure that consists of a manifold ontology of mind can, in turn, provide a more formal definition of analogy and account for the phenomenology described here. The phenomenological features that will be detailed below are: multiple analogies that serve to enumerate a category, multiple analogies that serve to analogy ?hop,? far-transfer analogies introduced before near-transfer analogies, constructing the base of an analogy rather than recalling the base from memory, a variable representation of that base, and analogies as offering an alternative to another way of understanding this phenomenon. Models of analogy from the literature To understand these phenomenological aspects of generated analogies, one might first turn to an established model of analogy. As noted in Chapter 2, these models, first 59 developed in the 1970?s, have evolved to the commonly accepted models of structure- mapping (Gentner, 1983) and MAC/FAC (Gentner and Forbus, 1991). The initial theories of analogy, commonly referred to as feature-matching theories, were based on similarities between features, properties and behaviors of the primary and secondary subjects of the analogy (Johnson and Malgady, 1980, Miller 1979, and Tversky 1977). It has since been widely recognized that the claim of ?similarity? is vague and underdetermines the correspondences and nature of analogical reasoning (Lakoff 1987). Similar claims were made in categorization: while members of a category were assumed to have certain features in common, defining these features was problematic. Some features, such as ?seat? for the category of objects called ?chairs? appear to have names that showed them not to be meaningful prior to the knowledge of the object as a chair. ?Large? for the object ?piano? has meaning only in relation to categorization of the object in terms of a superordinate category. And ?you eat on it? for the object ?table? is a functional attribute that requires knowledge about humans, their activities and the world (Rosch 1978). Similarly, analogies are not based on superficial attributes and feature- matching between subjects, but apply to a more abstract structure of the subjects. Gentner (1983) developed a theory, structure-mapping, to address the fact that analogies are not feature comparisons, but much more structural. Structure-mapping theory argues that interpreting an analogy involves both alignment and projection. The process is described in Bowdle and Gentner (1999): Structure-mapping theory assumes that interpreting a metaphor involves two interrelated mechanisms: alignment and projection. The alignments process operates in a local-to-global fashion to create a maximal structurally consistent match between two representations that observes one-to-one mapping and parallel connectivity (Falkenhainer, Forbus and Gentner, 1989). That is, each object of 60 one representation can be placed in correspondence with at most one object of the other representation, and arguments of aligned relations are themselves aligned. A further constraint on the alignment process is systematicity: Alignments that form deeply interconnected structures, in which higher-order relations constrain lower-order relations, are preferred over less systematic sets of commonalities. Once a structurally consistent match between the target and base domains has been found, further predicates from the base that are connected to the common system can be projected to the target as candidate inferences. There are several shortcomings of structure-mapping theory when trying to understand student-generated analogies. First, such a model is designed to explain ?interpreting an analogy? and not the process by which that analogy was created. 1 Additionally, while structure-mapping can illustrate what an analogy is, it is not clear why a student would map knowledge from one domain onto another, under what circumstances analogies are generated, or how the analogy will evolve in the classroom. Structure-mapping is a powerful model for how an analogy, once introduced and understood may be formalized and used to draw further inferences, but it is not a model for how analogies are generated and the kind of work this generation does. Analogies as categorization To address the phenomena mentioned above and understand the role of generated analogies, I will argue for a categorization framework; that is, I assert that the role of Miranda?s analogy between a falling cup of water and a toy cat swinging in a basket (first mentioned in chapter 3 and explored in detail below) is not to establish a one-to-one mapping between this particular cup of water and a particular instance of swinging a 1 In some references, structure-mapping is portrayed not as a model for how we interpret analogy, but generate (Falkenhainer, Forbus and Gentner, 1989 p 2): ?Structure-mapping decomposes analogical processing into three stages?: 1. Access: Given a current target situation~retrieve from long-term memory another description, the base, which is analogous or similar to the target.? 61 basket overhead. Rather, the cat/basket serves to represent a more abstracted, general category ? that of, perhaps, containers that do not spill their contents when overturned (though certainly not so well-defined in Miranda?s mind, and lacking the propositional structure that such a characterization implies). By constructing this category, she has introduced an alternative cognitive model, allowing for a new set of causal mechanisms to be explored. As this category is negotiated, adapted and understood, additional analogies are introduced as a means of negotiating and understanding this category. This idea echoes and expands upon claims made in cognitive science regarding the interpretation of metaphor. When the base of an analogy (termed the vehicle in the context of metaphor) is used as both an exemplar and as an ad hoc name for a category, Glucksberg et al. (1997) call this linguistic move ?dual reference.? As an example of dual reference, the phrase ?a responsibility is a shackle? can be used to refer to the concrete, physical device that is made of metal, often has chains, can be locked around someone?s arms and legs, and so forth, and it can also be used to refer to the abstract, general category of constraining entities. We refer to such abstract, general concepts as attributive categories. (Glucksberg et al 1997 p 334) The authors claim that ?nouns can be used to make dual reference whenever a superordinate category has not been lexicalized and a category exemplar is available that is prototypical of that category.? I will expand upon this idea to include more than nouns in metaphorical scenarios and focusing on the generation of analogies Again, in this chapter I will focus on the phenomenological aspects of generated analogies in science ? in particular, the pattern of multiple analogies, chains of analogies, near and far transfer analogies, analogy bases constructed as opposed to recalled, and the 62 variability of representation of the base in such analogies. In the following chapter I will focus on the underlying cognitive structure, cognitive models and ontology of mind that is consistent with this analysis. Multiple Analogies The first phenomenological aspect of student-generated analogies that I present is that of multiple analogies. In each of the following transcripts, an analogy is generated and then, in the negotiation of that analogy, further analogies are brought up. None of the following analogies is at odds with the initial analogy, nor are they extensions or modifications of that analogy, rather they are consistent with the initial analogy and, I argue, serve to aid in understanding the category ? the kind of thing ? that the initial analogy asserts. Below I present these multiple analogies and demonstrate the consistency between multiple analogies and a categorization framework of student- generated analogies in science. This chapter consists primarily of kind of checklist of phenomena that student-generated analogies have in common with categorization; in the following chapter I will account for this correlation in a more theoretical manner by addressing a theory of mind that can account for and explain these phenomena. Multiple analogies: Example 1 In Chapter 3, I first introduced the following analogy from a 5 th grade classroom in a rural Maryland public school. In this transcript, the students have been visited by the science resource teacher and posed the following question (NASA, 1999): a cup full of water is inverted on a cookie tray and the tray is rapidly pulled out from underneath the cup (see Fig. 4.1). What happens to the cup-water system? The students will later observe 63 Fig. 4.1: The Experiment: A tray pulled out from under a cup that the water does not leave the cup as it falls to the ground ? the cup falls at the same rate as the water and the water will only spill out once it reaches the ground. However, perhaps not surprisingly, the students initially predict that the water will spill from the cup or spread across the tray. A student then offers a different prediction and introduces the analogy (transcript 2, lines 8 ? 36) that the cup of water is like a cat in a basket and will not spill when overturned The claim that I will continue to make throughout this dissertation is that Miranda, with her analogy, is making the assertion that the cup of water belongs to a category or class of phenomena that is typified by the toy cat swinging in the basket, rather than mapping the structure of swinging a cat in a basket to the phenomenon of the overturned cup of water. Consistent with this story are the multiple analogies that ensue. Following Miranda?s introduction of the analogy to a toy cat swinging in a basket, the following analogies are introduced, consistent with Miranda?s analogy: throwing buckets of water (transcript 2, lines 134 - 144) Teacher: It could turn sideways like that. And that would make a difference. Okay let?s get ? a lot of you have been very patient. Cody? Cody: Um because when I was um having bucket full of water and I swing it around and then when I throw it the bucket of water still stays in there- the water, and? Yeah and then when I throw it the bucket of water still stays until it hits something. 64 throwing a bag of Halloween candy (transcript 2, lines 179 ? 189) and tossing dice in a hat, Isaac: Um I pre- I don?t- um I agree with Miranda but I don?t think air has anything to do with it. Because um yesterday at Trick-at-Treat I had like a bunch of candy and I swung it around that?s like when I was bored and stuff ? Teacher:In your bag? Isaac: Yeah. And none of the candy came out. I like kept on swinging it and also when me and Johnny play monopoly there?s like this little hat that we play with when we roll the dice [Teacher: Mmm hmm.] and like we always put the dice in and flip it back to each other with the dice in it and we always catch it and it stays and the dice stay in. and twirling Easter candy (transcript 2, lines 200 ? 207) Teacher:?Alexandra? Alexandra: Um when Miranda said how when she dropped the cat in a um basket- I?ve done that with um my Easter candy but with more candy in it and when I turned it over when I got up here and it dropped it all went everywhere. Teacher: But when you were swinging it, it didn?t fall out until you got up here and then stopped and then it all fell out. [Alexandra nods.] In the structure-mapping model of analogy, the role of multiple analogies is not clear: if students understand the target and base and their relationship to one another, the analogy has served its purpose and reiterations of this structure-mapping with additional analogies should not be necessary. However, multiple analogies are consistent with categorization, as categories typically consist of multiple members and these serve to better define and negotiate the category they are constructing. Researchers have shown, perhaps not surprisingly, that students? abilities to categorize properly are greatly enhanced when multiple members of a category are shown (Namy and Gentner, 1999) and these multiple analogies can be understood to be negotiations of the category Miranda is asserting. 65 What is surprising about these multiple analogies is that, although they are consistent with Miranda?s cat/basket analogy, they are not always introduced by students who agree with Miranda?s prediction: neither Cody, who introduced the bucket of water analogy, nor Alexandra, who brought up the Easter candy analogy, believe that the water will stay in the cup, and Isaac agrees with Miranda?s prediction but, without a rationale for why, disagrees with the suggested mechanism of this prediction. These students are not discussing the ?mapping? of a base onto a target: they are not relating their analogies to the cup of water, they have not put items in a one-to-one alignment or made candidate inferences, as structure-mapping suggests. Rather they are exploring the phenomenon of the toy cat in the basket in its own right by mentioning other members of the category that it represents ? that is, other items that do not spill from their containers ? as a means of negotiating the category to which the base of the analogy belongs. A particularly telling moment in the multiple analogies as categorization story is when Alexandra claims (transcript 2, lines 200 ? 207): Alexandra: Um when Miranda said how when she dropped the cat in a um basket- I?ve done that with um my Easter candy but with more candy in it and when I turned it over when I got up here and it dropped it all went everywhere. Teacher: But when you were swinging it, it didn?t fall out until you got up here and then stopped and then it all fell out. [Alexandra nods.] What does Alexandra mean when she claims to have ?done that?? What is that? No one ever explicitly discusses the abstracted ?category? of ?overturned containers that do not spill their contents?? and yet that cannot refer to the concrete example that Miranda mentioned: Alexandra does not claim to have spun a basket overhead. Instead, Alexandra, indeed the whole class, recognizes that Miranda is using the toy cat in a 66 basket as an instance of a more general category, one that Alexandra represents with her Easter candy and refers to by her claim to have done ?that.? In another use of ?that? to refer to the class of phenomena that her initial analogy constructs, Miranda, in line 55 (transcript 2), says: Miranda: And it?ll be the same thing with the water the air will push the water up until it falls down and then it will go everywhere. Because when it comes down the air is pushing upwards and [it keeps/I keep?] the water in there- because I?ve also done that in the bathtub when you?ve got your cup, I?ll like I?ll fill it with water put my hand and drop it the water stays in until it hits the bathtub and then it goes everywhere. To claim ?I have also done that? signifies there is a ?that? to refer to ? the category of phenomena to which the cat/basket, cup/water and Easter candy/basket belong. The use of ?that? is often indicative of categorization: imagine that you are telling someone about training for and running a marathon and she replies ?I?ve done that.? One would assume she means she has run a marathon ? not the same marathon as you, but rather recognizes the (slightly) more abstract category of marathons in general. For a more abstract case, consider the example from the previous chapter, in which a friend and I were discussing Moneyball (a story about baseball management) and he mentions that he is reading a similar story and brings up Bj?rk (an Icelandic pop star). Though I don?t have a transcript of our conversation, one can imagine saying, ?That?s a really popular story to tell these days.? In this case, ?that? would mean an abstracted type of story ? a category to which Moneyball and Bj?rk belong. Miranda?s analogy, then, is to instantiate this category of containers that do not spill when overturned ? construct it as a category and assert that the cup of water is a member. The other students understand this, come up with other members of the category that Miranda has constructed, and debate whether or 67 not the cup of water is, indeed, a member of this category and Alexandra?s comment to say that she has ?done that with um my Easter candy.? If the use of the word ?that? seems scant evidence for categorization to be at play, this is only due to the fact that categorization is so ubiquitous it frequently escapes our notice. Every conceivable noun describes a category, and every time I identify a window as being, in fact, a window, I am making a categorical assertion. Verbs, too, can be seen as categories; the claim ?I leap? makes a categorical assertion about the kind of activity I am doing, ignores the subtle differences between this leap and other acts of leaping ? just as running-a-marathon or swinging-something-overhead-so-that-its-contents-do-not- immediately-fall-out can be a category. While running-a-marathon is a relatively exact category (in this context), the nuances of many categories can be quite complex. Consider all of the ways in which ?leap? can be used: ?a leap of faith,? ?look before you leap,? a ?flying leap,? or ?leap frog.? Or, as Hofstadter (2004, p. 505) explains, such lists go on and on virtually forever, and yet the amazing fact is that few people have any inkling of the vastness of their mental lexicons (see Becker 1975). To be sure, most adults use their vast mental lexicons with great virtuosity, but they have stunningly little explicit awareness of what they are doing. And just as lexical items and phrases describe categories, there are categories for which we have no simple labels. As with the Moneyball/Bj?rk analogies, there are ?stories about someone who has an entirely different perspective on the ?system? and revolutionizes it despite naysayers to great success.? And in these categories, multiple members serve to negotiate and define the category. As a second example of the role of multiple analogies as defining and negotiating a category, I present another transcript of student conversations of science. 68 Multiple analogies: Example 2 The following transcript, first introduced in Chapter 1, is from an undergraduate physics course for elementary education majors, Inquiry into Physical Science. The students have been investigating the electrical properties of Styrofoam and metal, and noticed that Styrofoam is easy to charge (simply rub with wool) and metal is not, but metal can easily give you a shock and there are ways to charge metal once you have a charged object. They have been asked to explain the differences between these two materials by describing ?what life is like? for a charge in each. In doing so, multiple analogies are introduced. (In this transcript, by class convention, the two types of charges are referred to as ?top? and ?bottom.?) Hana begins the discussion with an analogy between the charges and fish (Transcript 1, lines 1 ? 17): Hana: I kind of see the charge in metal as like, fish in a fish bowl? Like they never really stop moving, they?re always kind of floating around wherever they kind of feel like going and that?s just how I see it in my head, like them always moving around. And I don?t know what hap- I don?t know how to describe it really I don?t really know what happens once another charge is brought closer then. Instructor: Does this make sense to you then? Hana: Yeah. Instructor: So this is ? so this is like two kinds of fish. [Hana: Yeah.] And in metal they can move around. They?re kind of stuck inside the bowl, but within the bowl they can move around. Hana: But I also think that they can leave the bowl at some point because ? Instructor: Well we get shocked right? This idea of continual motion of the charges is mentioned in another analogy (Transcript 1, lines 20 ? 33): Kelli: That same idea I was thinking except more like ping pong balls that bounce all around and that?s why if there?s top and bottom charges they?re moving around a lot and they?re kind of attracting 69 and repelling and attracting and repelling each other the tops and bottoms that go all over the place ? but once the extra bottom charge is added it?s almost trying to like reneutralize itself and the tops are attracting to the extra bottoms. And then they?re trying to kick out the other extra bottoms so they can get back into their whole little [Student: Balance.] balance. Bouncing around. Instructor: So this- I think what you?re offering is an explanation of why I get a shock. Is that ? am I wrong? Kelli: No, you?re not. In both analogies, the students are, first, introducing an imagistic analogy that describes the motion of the charges and then, in the case of Kelli?s analogy, explaining how, mechanistically, this is consistent with observed phenomena. However, a student notes the following (transcript 1, lines 46 ? 52): Christie: We were thinking that ? like they were saying that in metal it?s always moving, so if it?s always moving it has more room to move and that would mean to say that the molecules are less tightly packed together or less dense and we were thinking of Styrofoam as more dense than ? I?m just trying to figure out first if that?s right and how it relates. A second group of multiple analogies stems from Christie?s comment, ?If it?s always moving it has more room to move and that would mean to say that the molecules are less tightly packed together or less dense and we were thinking of Styrofoam as more dense...?. The students are all in agreement that charge seems to move more freely in metal than in Styrofoam (as in the analogies to fish in a fish bowl or ping pong balls bouncing all around), but this seems to imply that there is ?more room to move? ? meaning that metal should be less dense than Styrofoam. Lea, picking up on the fact that metal is more dense than Styrofoam, constructs an analogy that incorporates both: the Styrofoam is like cotton while the metal is like ice skating, in which the density of the medium allows for easy movement (transcript 1, lines 53 ? 60). This category, media 70 whose density allows for movement, is non-intuitive: crowds are hard to walk through, syrup is hard to walk through. In understanding and negotiating this category, other analogies are mentioned: a sponge, whose lack of density is a trap for water versus the dense countertop that allows water to flow easily (transcript 1, lines 61 ? 66): Instructor: Lea I want to add ? I think you?re sort of what I when I hear you talk I?m thinking of like, pouring water into a sponge versus pouring water onto a hard surface. [Lea: Yeah.] Like this sponge is actually less dense and there?s room for it to absorb the water and the you know if you pour it onto something hard there?s no room for it to absorb. And later another analogy, consistent with the previous two is mentioned ? stepping stones that, when far apart, inhibit easy passage but when densely packed are easy to negotiate (transcript 1, lines 113 ? 121). Lydia: I was going to say I think the pie plate is more dense but I do think that it?s inside not outside because if there?s more space to travel then the molecules can?t get from one space to another easily but it?s all real close together so it can sort of hop along inside. Instructor: Oh so it?s like stepping stones [Lydia: Kind of.] like in the Styrofoam it?s really far to the next stepping stone so it?s like can?t get there I?m stuck here. [Lydia: Right] but in the metal the stones are really close together so I can kind of walk across. [Lydia: Yeah.] I will revisit this analogy in the following section for the manner in which it differs from those that came before. In the above transcript there are several analogies mentioned: - charges are like fish in a fishbowl (lines 1-4) - charges are like ping-pong balls (lines 20-24) - metal is like ice-skating (lines 56-57) - Styrofoam is like a sponge (line 63) - charge flow is like steam escaping a shower (lines 98-104) - metal is like a set of closely spaced stepping stones (line 120) 71 Some of these analogies are mentioned relatively independently, but, as in the case of Miranda?s analogy and the multiple analogies around it, some analogies in the transcript above further develop a category that the original analogy has constructed. Chains of Analogies A second manner in which multiple analogies are used is not to flesh out a category, but as a means of ?stepping? from one analogy to another. In this section, I will present examples of analogies that are not consistent with one another but can each be seen to be a slight ?tweak? on the one that came before. Such analogies are consistent with findings from categorization ? in particular family resemblance, described below. It is important to note that research indicates categories do not have a fixed representation or set of criteria for membership. Our categories are constantly reshuffled and recast depending on the context. At times, the concept of leaping is very much related to movement, at other times to lack of support, and no dictionary definition can capture the full character of the way this word is used in everyday language. As noted in chapter two, ?there is no one property that all games share, but rather there are family resemblances between games, so that ?chess and Go both involve long term strategy? chess and poker both involve competition. Poker and old maid are both card games? (Lakoff, 1987 p. 16). Similarly, ?leap-frog? and a ?flying leap? indicate a kind of forward motion off of the ground, while a ?flying leap? and ?look before you leap? are situations in which you lack support. This family resemblance is indicative of two things: one, as mentioned above, that no one characteristic defines a category, and two, there is a hierarchy of categorization. Rosch referred to the most accessible level ? the 72 easiest to learn, recognize, recall, and shortest to name ? the basic level and underlying this level are more fine grained categorizations: such as games dividing into card games. If analogies, then, are assertions of categorization, we might expect multiple analogies as a way of negotiating the category, and chains of analogies (as with Go, chess, poker and old maid) as family resemblances are followed within a category, subdividing that category into a finer grained one. The analogies in the previous section are relatively consistent with one another as a particular category becomes increasingly defined. In this section, I present analogies that follow chains of ?family resemblance? to tease apart distinctions and more narrowly define a particular categorization. Chains of analogies: Example 1 The first transcript below is from a research group meeting of the Physics Education Research Group. Paul, a graduate student, is interested in authentic classroom activities and is discussing his definition of authentic. Key to this definition is that authenticity is a property not only of the activity but also but also in the way that the students relate to that activity and the coherence of this to the scientific community of practice (that is, do the students know what they?re doing? Would scientists agree?). This is at odds with definitions of ?authentic? activities that situate authenticity as a property of the curriculum itself. In this transcript, analogies to authenticity are suggested, and multiple analogies are pursued. These analogies are both along the lines of honing in on and refining a particular analogy (akin to the multiple analogies above) and ?family resemblance? analogies that are more ?horizontal? than ?vertical? chains. The transcript begins with David recapping Paul?s concerns with the standard definition 73 of authentic curricula, and Rachel?s introduction of an analogy between ?authentic? and ?fun? (transcript 3, lines 1 ? 9): David: It?s not a responsive definition of authentic. Authentic is defined pre-experience. And so what your [Paul?s] sense is what?s going to be authentic is about watching the student and and what is authentic for this group ? may be different from what?s authentic science for this group. And you don?t like defining authenticity in a way that isn?t responsive. So the content isn?t responsive but also the sense of what is authentic isn?t responsive. Rachel: So ontologically authenticity is like fun. Which would be ? David: Oh that?s great. Andy: Oh that is beautiful! The analogy is understood by the group and further explained in lines 17 ? 29 (transcript 3): Andy: ? it emerges from an activity but it?s really ultimately lives inside ? Rachel: Right and I mean you could say ? I mean you couldn?t look at a thing on paper and declare that it was fun until you could see people do it and see them have fun. David: And it may be fun for some people and not fun for other people. Andy: You could ? an experienced teacher could make guesses about what?s more likely to result in fun blah blah blah. Rachel: Sure, sure. But really ultimately you don?t know until after [inaudible]? David: Or anyone ? what what my kids think of as fun might not be the same as what Rachel thinks of as fun [trails off]. However, a weakness of the analogy is identified: Paul has argued that authenticity must not only be recognized by the students? relationship to the curriculum, but a (hypothetical) community of practice must have a similar understanding of the relationship between the students and this curriculum. This weakness is identified and alternative analogies are proposed (transcript 3, lines 38 ? 70): Leslie: Is there a community of fun practice? [Laughter.] Rachel: Or norms? [Laughter.] Leslie: Like with the community of practice the scientist is someone who?s outside deciding whether or not it was science but with fun 74 there isn?t ? so it?s a negative analogy ? but with a community ? yeah there?s no community of practice. David: I don?t know what you mean ? there?s no authentic community of practice? Leslie: You only have to ask a person who?s having fun if they?re having fun. But this (definition of authenticity) implies that you have to ask the scientists whether they?re doing science. David: Ahhh ? right. Gotcha. Andy: Not only does it have to be meaningful it has to be meaningful in the right way ? but ? yeah I?m having fun but it?s ? you know ? low-brow fun instead of highbrow fun. Guffaw guffaw! Gotcha. [Laughter.] David: So can we patch that? Is there, is there another? Rachel: Good clean fun?... Leslie: I have a multiple analogy if that?s okay? I?m thinking it?s more like worship ? like, you know if you?re worshipping but a religion is going to also decide if what you did was worship. Andy: Oooh. David: Right. Right that?s good. Andy: It?s gotta pass both tests. That is good. Good clean fun works, too. You decide if it?s fun, I decide if it?s good and clean! [Laughter.] Leslie: Or pornography? The analogies above construct a particular ontology (as Rachel identifies) ? or category ? of adjectives: those that are not inherent properties of the object they describe, but, like ?fun,? are a measure of both the activity and the participant. This does not quite describe the sense in which Paul is speaking of authenticity. In his description of an authentic activity, Paul also relies on the coherence of the students? understanding of the activity with the community of practice?s understanding of that activity. To patch the analogy, two alternative analogies are suggested. One is a more ?vertical? analogy: replacing fun with ?good clean fun? (line 60). I say vertical because this is similar to looking at games and then honing in on ?card games? because the category ?games? is too vague and lacks the detail that ?card games? has. An alternative ?patch? is to move more ?horizontally? ? 75 as if moving from ?games of chance? to ?card games? as Leslie (I) does by suggesting ?worship? or ?pornography? as alternative analogies. The multiple analogies presented above do not serve the same role as the multiple analogies presented in the previous section. Instead of serving to negotiate and understand the category that the analogy constructs, they alter this analogy ? however they do so in a manner consistent with categorization. One possible ?tweak? to a category is to further parse it ? categories have hierarchies (as with ?chair? which is a base level category ? and ?easy chair? or ?desk chair? or ?recliner,? which are subdivisions of this category). Taking the idea of ?fun? into ?good clean fun? is such a move. An alternative move is one of ?family resemblance? in which categories are related to one another within a hierarchy (as with ?easy chair? and ?desk chair?) ? it is this move that Leslie makes in moving from ?fun? to ?worship.? Chains of analogies: Example 2 Furthermore, these analogies, unlike the multiple analogies that are consonant with the cat in the basket, are in response to something problematic ? a small piece of the story doesn?t work out. This is the story in the final analogy presented in the analogies regarding charges in metal (transcript I, lines 113 ? 121) in which the metal is like closely-spaced stepping stones. Implicit in the analogies that the other students have suggested is that the charge will then travel on the outside of the metal: ice-skaters travel on top of ice and water travels on countertops ? implying charge will travel on the outside of metal. This is very much a structure-mapping story, in which the structure of the base makes implications for the target: items in the base and the target are placed in a one-to- one alignment and inferences are projected from that alignment. Charge traveling on the 76 outside of the metal is an inference that structure-mapping can predict and explain. In this regard, structure-mapping tells a story that is an important piece of the work that analogies do in science classrooms and in science, and address a part of analogies that I do not: how they are used to draw inferences and establish a sense of mechanism. My claims are not regarding Lydia?s interpretation and understanding of these implications, but how they in turn construct new analogies. This implication is one that Lydia challenges. (I note that) The ?tweak? to the analogies is then suggested by the instructor, who moves from a countertop analogy to a stepping-stones analogy. Chains of analogies: Example 3 The following transcript from a third grade classroom presents another example of this ?family resemblance? property of multiple analogies. In this classroom, the teacher, Trisha Kagey, has asked the students: if you are running with a beanbag and want it to fall on an X, should you release it before, when, or after you reach the X? In the discussion that follows, several analogies are introduced, many of which are slight modifications of the one that preceded it. Below I present transcripts from the chain of analogies: - the beanbag is like a baseball bat (line 59) - it is like a leaf being dropped from a bus (line 74) - it is like a rock being dropped from a bus or a bike (lines 36 and 76) - the leaf is like a feather, and a rock is different (line 136) - the rock is like a tree and yet made from the things that are different (188) The first analogy is mentioned (in transcript 4, lines 35 ? 46) after Adam argues for his prediction with Newton?s Laws. I present it here for completeness: this analogy is not a part of the ?chain? of analogies that ensue but the teacher?s instructions and the student?s 77 analogy may play a role in the other students? expectations about what kind of knowledge to bring to bear on the question: Teacher: ?but trying to just explain it to someone using your experiences ? see if you can use it that way. Explain to ? like you?re explaining to a kindergartner. They?re not going to be able to understand that law. Adam: Like um ? if ? like if something ? if you?re riding your bike, um ? it?s in motion. And you?re going to keep going until you get stopped by like ? um, a rock or something. And, and ? or going uphill. And so if you?re on a bike, and you get ? you can get stopped by something else, like a rock or something. Teacher: So if we?re thinking of your analogy to a bike, or your explanation with a bike, what?s stopping it, and this is ? Adam: Um, no. Well, in the situation of dropping the beanbag. Like, um, it?s thing is the ground, and because the beanbag is running against the ground, um ? it?s getting slower. Because like the beanbag is um ? getting ? I don?t know how to explain this. Connor, in lines 55 ? 62 (transcript 4), does not address Adam?s prediction and explanation, but instead offers his own analogy: Connor: I would think the bean bag would ? might fall behind where you want it to fall because when I put ? when I played baseball ? they always said don?t throw the bat because it might hit the catcher and not one of the um person because we?re using metal bats, and ? so we drop it, you drop it and then you ? . Well, when I drop it, it usually swings backwards; it wouldn?t be behind the plate instead of the front of the plate. Connor?s analogy changes as he considers it further (transcript 4, lines 71 ? 78): Teacher: Why do you think it fell behind? Connor: Well actually it didn?t mostly. It got on the side or in front because ? well because you?re supposed to drop it because you don?t need a bat while you?re running the bases. Once you drop it, I?m just thinking also, what Adam is ? well a bus ? well if you were on a bus and you had uh, this little leaf that you found, and the window was open, and you drop it, it will go ? it?ll be going backwards. It is interesting to note that the original analogy that Connor introduced should lead him to predict that the beanbag falls ahead of you when you drop it ? and the analogy he then 78 offers that is consistent with his prediction is a scenario that he has not likely done. This phenomenological aspect of analogies will be explored later in this chapter. In terms of the chain of analogies that is being constructed, Connor has moved from the very similar running-drop to dropping from a bus. In lines 83 ? 94 (transcript 4), another student challenges Connor?s analogy and he tweaks it further: Lauren: Because I think that?s cause ? you?re talking about a leaf that?s falling? That?s because the ? it?s sort of ? the bus is going back, so it?s making like the air move. And the leaves are really, really light, so the reason they are going backward is because ? . Um, well it?s going so fast ? a bus is like going so fast that it?s probably making the air go that way. So that way the leaves are going that way. [Many talking in disagreement.] Connor: What if you did it with a rock? The same thing will probably happen with a rock. Because you are probably like a bus, that you make the air come ? no one moves, don?t you notice that um, objects like in cars or something ? when you?re going really fast on your bike that are ? that um, you sometimes, [inaudible] and leaves your ankle on your back step and actually move. The distinction between the ?little leaf? and the rock are considered in lines 146 ? 150 (transcript 4), and an analogy between the leaf and a feather are drawn: Kamran: But, if you ? cause you know a feather is ? it, it, it goes with the air just simply its a light. That?s why ? same with a leaf. A leaf is very light. And if you ? a leaf falls [Inaudible.] goes to air. It doesn?t go, ?leaf ? boom.? It doesn?t go like that. And then (transcript 4, lines 188 - 190) the idea of the leaf is tweaked into considering the weightiness of a tree: Kamran: Yeah, because the weight pulls it right down. If a tree ? it?s heavy, and it?s heavier than all the leaves it has, so the leaves will make it fly. Through these analogies, we see the students following a chain of reasoning that begins with a particular phenomenon ? that of the running drop ? and steps through a series of 79 family resemblances to arrive at two subcategories of the running drop phenomena. Kamran?s comment (line 188) explores some confusion in the distinction in these categories, saying ?the weight pulls it right down. If a tree ? it?s heavy, and it?s heavier than all the leaves it has, so the leaves will make it fly ? flies here. And the tree, it will just go down.? These two sections have demonstrated that a feature of student-generated analogies in science is multiple analogies. At times these analogies that come up in student conversations are independent of one another, but often they are related and this property is one that is neither predicted nor explained by current models of analogy. The predominant model of analogies ? in particular analogies in science ? is that of structure- mapping. This model is admittedly designed to explain analogies that have been constructed and the role that they then play. However, as shown above, it cannot account for multiple analogies. Categorization, which inherently involves multiple members and has been demonstrated to relate items not through any set of formal rules but rather through family resemblance, more coherently captures the manner in which spontaneously generated analogies in science are constructed and negotiated. In the following two sections, I will focus on the choice of the base for the analogies that students generate: first focusing on the base as a construction as opposed to a recollection, and then considering the role that similarity to the target of the analogy playas in the selection/construction of this base. 80 Construction of the base Depiction of the base in research on analogies Analogies are often depicted as a mapping from a well-understood base to a less- understood target, and implicit in this depiction is that the base is something that was previously known, experienced, considered, and then, during the act of the analogy, recalled. The following quotes (with italics added) about analogy reveal this assumption, in which the analog (or base) is ?retrieved,? ?stored in memory,? ?accessed,? and ?in memory,? but not ?constructed? or ?created?: ? ?A theory of analogical reasoning must explain how an analog is retrieved.? (Vosniadu and Ortony, 1989 p 7) ? ?Given a current target situation, retrieve from long-term memory another description, the base, which is analogous or similar to the target.? (Falkenhainer, Forbus and Gentner, 1989 p 2) ? ?Mental experience is full of moments in which a current situation reminds us of some prior experience stored in memory? (Gentner, 1989 p 199) and, ? ?the chronological first step in an experiential learning sequence is accessing the potential analog.? (p 200) ? ?Analogical problem solving involves three steps, each of which raises difficult theoretical problems. The first step involves accessing a plausibly useful analog in memory?? (Holyoak and Thagard, 1989 p 242) Not all researchers describe analogy in this way. Anderson and Thompson (1989, p 267) note that the base of an analogy can come from someone?s ?own past? the behavior of another?or it might come from adapting an example given in a textbook. The source for the analogy can be either an explicit experience or a generic or schemalike representation.? However, explicit reference to generated analogies as having a base that is constructed rather than recalled is rare. 81 Prototypes in categorization Categorization research has a similar history, beginning with theories of category representation as static things stored in memory and recalled for the purposes of judging category membership. Though there is no single theory of prototypes and the graded structure of categories, it was originally argued that a category was represented by a single representation, which was an amalgam of all exemplars stored in memory. Judging whether or not a new item belongs in a category involves comparing it to this amalgam. And this involves recalling all known instances of the category to construct a ?typical? exemplar that is ?a unified representation rather than separate representations for each member.? (Murphy, 2002 p 42) To address concerns with this initial theory, the idea of ?feature combination? was added, in which features that are averaged together are first combined, so that ? people keep track not just of individual features but configurations of two or more features. For example, perhaps people notice how often bears have claws and eat garbage, or have fur and are white ? that is, combinations of two features. (Murphy 2002 p. 45) Concerns with the computational demands these theories make on memory and recall, schema were introduced. A schema is ?a structured representation that divides up the properties of an item into dimensions (usually called slots) and values on those dimensions (fillers of the slots). Features of exemplars were then stored with a given weight into particular slots. An alternative to this (typically called the ?prototype view?) is the exemplar view, in which every instance in memory is used in the construction of a category rather than the average of these. While both the prototype and the exemplar view proved generative and had great explanatory power, their representation of mind 82 was problematic and the categories they sought to describe proved to be quite narrow, as Barsalou?s research in ad hoc categories and point-of-view categories shows. Construction of the prototype Barsalou?s (1983) studies of ?ad hoc? categories addressed categories that cannot be interpreted as fixed cognitive structures, such as ?foods not to eat when on a diet,? or ?things to do at a convention.? These categories, which maintained the phenomenological properties of more conventional categories (such as a graded structure), could not be explained simply using the exemplar and prototype theories. Surely, Barsalou argued, one does not store information on such detailed categories but rather constructs it. In later research (Barsalou, 1987) extended this idea, asking participants to take the point of view of a professor, Chinese person, or ?redneck? in judging membership in categories. Again, these categories displayed a phenomenological consistency with conventional categories but, again, could not be stored representations. Barsalou argues that ?rather than being retrieved as static units from memory to represent categories, concepts originate in a highly flexible process that retrieves generic and episodic information from long-term memory to construct temporary constructs in working memory? (Barsalou 1987). This is not meant to imply that there is not stable knowledge in long term memory, but rather that the concepts in working memory ? the ideas that are pondered, discussed, articulated and reasoned with ? are temporary constructs and, as such, sensitive to context and goals and inherently unstable. This interpretation of categorization Murphy (2002) contrasts with the prototype and exemplar views, referring to it as the ?knowledge view,? in which ?part of 83 categorization and other conceptual processes may be a reasoning process that infers properties or constructs explanations from general knowledge.? (Murphy, 2002, p 60-61) It is this picture that is missing from most analogy research. In part, this is because the focus of analogy research on how people understand a given analogy ? in which case the base of the analogy is present, and one must recall information about that base. It is also due in part, perhaps, to the analogy of the mind to a computer in which context and knowledge construction is irrelevant. However, when paying attention to the analogies that students create when discussing scientific ideas, these analogies are not always drawn to a well-understood base. Rather, the base may be a construction, as with our representations of categories. Construction of the base in student-generated analogies In the transcripts above, bases that are clearly not recalled from memory are most profound in the beanbag transcript. In line 64 of this transcript, Connor has predicted that the beanbag will fall backwards and has drawn an analogy to dropping a baseball bat. When the teacher asks ?Why do you think it fell behind?? He, surprisingly, notes ?Actually it didn?t mostly.? And then he selects a more appropriate analogy: ?if you were on a bus and you had uh, this little leaf that you found, and the window was open, and you drop it, it will go ? it?ll be going backwards.? While it is possible that he has dropped a ?little leaf? from a bus window, he does not claim to have done so and it is reasonable to imagine he hasn?t. And in line 91, his suggested analogy ?What if you did it with a rock?? is based more on a sense of theory than a past experience. Instead of recalling this experience from memory, he is constructing it from ?a reasoning process that infers properties or constructs explanations from general knowledge? (Murphy, 2002 84 p 61) ? as has been argued happens in the construction of representations of categories. Kamran, in line 154 (transcript 4), makes this searching for a representation from principles (rather than from memory) clear as he reasons through possible analogies: ?A rock is different, a rock has ? it?s also like, it?s solid, but it?s not that a leaf isn?t solid, or a feather isn?t solid. A feather ? but you have to ? it?s very small, and it?s very like thin, so you kind of say like solid. But anything hollow, like if you have a paper box?? A second example of such construction of the base of the analogy comes from the Physics 115 course. Students were asked to make sense of several phenomena of circuits. In one course, an analogy was suggested: imagine a vacuum cleaner sucking up beads, and the light bulbs were like small filters in the tube of the vacuum cleaner. In another course, the analogy was drawn to a hose that is already full of water (so that it takes no time for the bulbs to light) that has small holes in it (which represented the light bulb). In each case, the students are seeking to explain their reasoning via an analogy that they have constructed rather than one they are simply recalling. Again, this underscores the fact that students are not mapping from a well-understood base onto a less-understood target. The consistency of the constructed bases of analogies will be explored in the following chapter, in which I will show that these analogies are constructed from the schemas or p-prims that the students have activated; for now it is important to note that, consistent with the spontaneous construction of categories, the base of an analogy can be a spontaneous construction. A final example of the constructed base of analogies comes from two undergraduate students who are trying to solve a problem in their quantum mechanics homework assignment. In this problem, they are asked to find the total angular 85 momentum, which the first student, Ben, believes you can answer from first principles. Anselm argues that understanding a simple case does not necessarily mean that you will be able to solve the more difficult problem, and explains this using a constructed (as opposed to a recalled) analogy (transcript 5, lines 15 ? 27) 2 . Ben:We should be able to figure this out from today?s lecture. Anselm:No you shouldn?t. Ben: He?s gonna explain in detail probably Wednesday how you actually get to J [the total angular momentum]. Anselm:But see you?re doing the wrong thing. ?Cause you?re assuming that if you have the example: ?suppose there?s a charge here, what?s the electric field due to it?? You can figure out ? suppose you have Bugs Bunny, and he?s charged, what?s the electric field around his ears? Alright? Because you have a simple example when they?re both the same, you?re not going to be able to figure out exactly what you?re supposed to do when the rules weren?t the same. I will revisit this transcript below for its evidence of a variable representation of the base of the analogy ? here I would just like to note that Anselm?s analogy, ?suppose you have Bugs Bunny, and he?s charged, what?s the electric field around his ears,? is not a problem that these students have been assigned in the past and tried to solve. Rather, Anselm is constructing this as a representation of a category of problems that cannot be solved from first principles. The category is an ad hoc construction and its representation, Bugs Bunny?s electrically charged ears, are similarly an ad hoc construction. Constructed, I argue, by categorizational reasoning; and clearly not a map from a known base to an unknown target. 2 Ray Hodges, who was a TA in the room with the students at the time, aided in this interpretation of these comments. 86 Near and far transfer analogies Research on prototypes and research on transfer The initial research on categorization established a graded structure of categories, in which some members are recalled more quickly and with greater frequency than others, are judged to be better exemplars of the category and are recognized as category members more rapidly than others. Theories behind these effects are varied and will be explored in the following chapter but, as explained in the above section, it is not due to simple feature matching, but seems to be rooted in reasoning processes and explanations. Analogy research has shown that near-transfer analogies are far more easy to achieve than far transfer analogies ? where near-transfer refers to analogies that are within-domain or have similar features, while far-transfer analogies are those that bear little superficial resemblance to one another. As explained in the previous chapter, however, this may be an effect of the particular style of research being conducted and the lack of meaningful context in which the analogies are situated. And, contrary to this research, ?far transfer? analogies do occur in student discourse and are not uncommon. If one interprets analogies as categorization, then perhaps the ideas of near and far transfer are not relevant. Instead, one would expect the base of the analogy to be, instead of superficially near, prototypical of the category. In this section I will present evidence that the base of analogies are not chosen for the similarity of features or ?nearness.? Arguing that the choice is, instead, prototypical requires appeals to theoretical considerations that will be addressed in the next chapter. 87 Examples from student-generated analogies Returning to the cup/water and cat/basket set of analogies, Miranda (line 59) claims to have done something that is quite similar to the case in question (involving cups, water, and dropping), but her initial analogy to explain her reasoning came from a much less similar experience. In line 25, to explain why she believes water will not spill from the cup as it falls, Miranda offers the analogy of spinning her toy cat overhead in a basket. Later, in line 59, Miranda says: ?I?ve also done that in the bathtub when you?ve got your cup, I?ll like I?ll fill it with water put my hand and drop it the water stays in until it hits the bathtub and then it goes everywhere.? If the base of the analogy is arrived at through a process of retrieval from memory, as many models of analogy imply, one would expect near-transfer before far-transfer, as the similarity of features would be key in retrieving the analogy. If, instead, the base of an analogy is a construction from this categorization, one would expect a base that is prototypical of the category it is asserting; near and far transfer are not significant questions in this framework. Rather, that the cat/basket analogy is chosen first, is much more convincing and is referred to repeatedly in the classroom can be understood by its prototypicality (or centrality) in the category it serves to describe. Additionally, concerns that Miranda is ?making up? the analogy to the cup in the bathtub (this concern has been voiced in discussions with others regarding the analogy) are not important: given that Miranda chooses these two analogies, regardless of whether they are experienced or fabricated, she does so in this order and the class responds to them in this way. Miranda serves as a particularly powerful example because she refers to two analogies and chooses the ?further? analogy first and it is this analogy that holds sway in 88 the classroom and is repeatedly referred to by the teacher and students. Far transfer analogies are not at all uncommon. Other examples from analogies above are: ? comparing a cup of water to a toy cat in a basket ? envisioning electrical charges in metal as fish in a fish bowl ? drawing an analogy between motion of charged particles in Styrofoam and the motion of water through a sponge ? drawing an analogy between motion of charged particles in metal and using stepping stones ? comparing dropping keys on an x to hitting a rock on your bike, and ? explaining your approach to solving a total angular momentum problem to solving a problem of the electric field around Bugs Bunny?s ears. While many of the above analogies are creative and intriguing, none are outside of the bounds of ?normal? conversation in science, and in many cases a superficially ?closer? analogy could seem too close and a more strange statement to make than the far transfer analogies. In the next chapter I will argue that these analogies ? the ?far? analogies ? are appropriate and, indeed, expected over near transfer analogies because of their relationship to the category that they serve to represent. Variable representation of the base In an effort to understand analogies, the majority of research from cognitive science and education has focused on the comprehension of analogies provided by the researcher or teacher, or the application of a desired analogy (for example, in Holyoak and Thagard?s study of transfer). Such studies limit the variability of representations of concepts that researchers can observe. The study presented here originates in research on student inquiry in science classrooms. These classrooms place a premium on student reasoning and explanation of ideas, and, as such, allow for student-generated analogies (which are far more rare in a classroom with a focus on content goals over process goals). 89 In this section I will present two different kinds of analogies: one set of analogies are presented to explain different ideas about the mechanisms of a scientific phenomenon; the second set are analogies used to explain the speakers? conceptions of the epistemological type of scientific phenomena ? that is, what is the nature of knowledge that applies to this phenomenon. In each case, the representation of the concept to which the analogy is drawn is chosen from among many possible representations, and categorization, because of its fluid nature and flexibility, can explain this choice of representation. Variable representation: Example 1 In the following transcript, there are multiple possible representations that the base can take, and the one that is taken depends on the conceptions of the target. While not entirely in discordance with structure-mapping (the process of alignment could be considered choosing the representation), a categorization framework shifts the importance and nature of analogy; when someone says ?a is like b? they are not saying: ?the structure of this one thing, b, has a lot in common with the structure of this other thing, a.? Instead, the assertion of analogy is more akin to ?a belongs to a class of things typified by b ? it?s the same kind of thing.? Where a ?kind of thing? defines a (often ad hoc) category and more may be brought to bear on a than just the relationships that exist in b. This first transcript below is of non-science faculty at the Governor?s School of North Carolina. In the lounge of the faculty dorm, they are discussing what happens to a rock in space as it receives energy from the sun: will it heat up indefinitely or only to a certain point? And if it only heats up to a certain point, why does it stop there? This rock 90 is referred to as ?David? because of a previous conversation about the differences between humans and statues (namely, Michelangelo?s ?David?) in space. Marc is content to say that David will reach a certain temperature and stay there, and explains this using an analogy. Note that Marc prefers a ?water? analogy of light, and is able to take on a ?money? analogy of light that is contradictory to Vic?s ?money? analogy of light. This demonstrates that, one, the choice of base in an analogy is one of ontology and, two, the base can shift representation according to the ontology ascribed to the target (transcript 6, lines 471 ? 498). Marc: Okay? let?s ? let?s say David is in a shadow, right? Okay- he enters the sun. The sun bombards him with all this energy right? So in a second it?s now at 5 degrees. Can it radiate heat that fast? No. So in the next second it?s 10 degrees. It?s now radiating a little bit more heat but there?s more energy coming in. So it gets to 15 degrees. But at some point it?s radiating enough heat to stabilize at 20 degrees. Steve: But why? Cameron: What? Marc: Or let?s think of think of like a, think of like a basin, ok? Think of a tub. With the drain open, okay? The drain is open. Now if I open the spigot [Uh huh.] ? if I open it too slow then the tub doesn?t fill. But if I open the spigot fast enough there?s water filling up the bottom, and yet some is also draining out, right? [Right.] If I open the spigot up fast enough it doesn?t matter if the bottom is open, the top will overflow but at some point if I reach the right point the tub could stay at a certain level, even if water?s going in and water?s going out, right? If they came in at the same rate [Steve: Right, but ? ] the tub would fill up. Steve: But that?s ? what?s David?s drain? Vic: That?s ? this is my question. What?s David?s drain? Tom: Well, what?s the sun?s drain? The sun is clearly radiating heat and energy. Marc: Yeah I mean that?s just the ? Steve: The sun is radiating light. The conversation continues, and over the next three minutes Marc suggests that things radiate ? it?s just what they do; like a drain and like the sun, the rock gives off ?radiation 91 and stuff.? To explain why we can no longer see the radiation when the rock re-radiates, Marc offers that the light changed from a visible form to a non-visible form. But how ?ROYGBIV? (the colors of the rainbow) become ?infra-ROY? bothers Vic. The analogy of light as water and a rock as a tub contrasts with the analogy that Vic invokes to point out a problem in Marc?s re-radiation explanation in the following transcript (transcript 6, lines 1038 ? 1054). Vic: Wait wait wait ? every ? everybody is payin? me money. Everybody is paying me money in different forms ? in dollars, five-dollar bills, twenty- dollar bills. [Marc: Okay.] I?m savin? all of my one dollar bills that I don?t give away ? I do not spend any of my dollar bills on anything ever. Which means that I am gradually accumulating one-dollar bills ? even if I?m spending it in fives and tens and twenties. So what do I do when I end up with a thousand dollars in one-dollar bills that I don?t know what to do with? Marc: I?m gonna change that analogy [Others: Groan.] ? or I could keep it! I could keep it! Okay? I?ll keep it. Fine ? you know what I?m gonna do with those one dollar bills? Vic:Tell me. Marc:Well ? those dollar bills become ? you, you spend 50 cents of it in terms of heat and you throw the other 50 cents of it away but we can?t see those 50 cents because we?re only attuned ? Tom: You?re losing the analogy. The choice of this analogy is a largely ontological choice: Marc has a ?water-like? ontology of light and one can imagine that, just as turning a cup of water into two half- cups of water needs no mechanistic explanation, turning red (a high energy wavelength) into infrared (a lower energy wavelength) does not require further explanation ? it happens ?by the virtue of your existence.? Marc is making a claim about the kind of thing that light is ? it belongs to the class of things that water belongs to. This class could be described as a conserved quantity that does not come in discrete chunks and flows easily from one ?container? to another. Vic has a different conception about the kind of 92 thing that light is ? one that is organized in discrete quantities and matches the category that currency might belong to: net wealth does not count quarters as different from dollar bills, but in terms of actual objects, they are physically different and do not ?mutate? into one another. That this analogy is a statement of categorization (the kind of thing that light is) is evident in the objection that Tom believes Marc ?loses the analogy? when he violates this ontology. Marc, though he wants to ?change that analogy? is able to take it on by representing money in as a ?fluid? ontology. It is reasonable that money could be conceptualized in the manner Marc intends: when conceiving of someone?s bank balance, it makes sense to think of money as belonging to the ontology of fluids: if I deposit a quarter my bank will certainly allow me to withdraw a penny. And gas stations routinely charge to the tenth of a cent (or at least to the nine-tenths!). Structure-mapping and other interpretations of analogies that assume a particular conception to the base of an analogy miss the point that the claims are being made to signify a class of objects, and that a base and target can have multiple representations and belong to several different classes (or categories). Variable representation: Example set 2 In this section I present three transcripts: the first two are conventional analogies ? the ?tree in the forest? conundrum (albeit with slightly different features), and ?apples and oranges? ? and the third is a novel analogy regarding Bugs Bunny and electric fields. The first two analogies are intended to establish the categorization model and provide a means of interpreting the third analogy: if the first two are instances of categorization, as I believe is apparent, then so must be the third. And, as with the variable interpretations of ?money? (as fluid and divisible or ?hard? currency), the base of these analogies may 93 be interpreted in many ways. Furthermore, to echo a prior claim, the third analogy is novel and cannot be argued to be a well-understood base that is recalled from memory but rather is constructed on the fly to represent an ad hoc category. The first transcript is from a conversation in a 5 th grade classroom. The class has been discussing light and heat and the relationship between the two. After reasoning that light ?contains? heat because sunlight feels warm, Lisa notes that the light from overhead fluorescent lights does not make you hot (transcript 7, lines 86 ? 102). Lisa: I think that sometimes, well, most of the times, light is not always containing heat. Like, like this light up here, it?s not con ? it?s not, its not ? Dashawn:Burning? Lisa: Yeah, like making you hot. Kyle: Yeah it?s not making anything hot. Anna: But it's just ? what if you go up there and touch it? It would ? ? Brian: That's because your finger is an object. When it hits something it?s hot. Teacher:Oh, I see. So you get, there's a reaction when you touch light. Brian: But it's also a question like, um, if a door slams ? if a locker door slams and no one?s around to hear it, does it make a noise? Because you don't know if ? if you don't touch it and the light is making heat and making the air hot. You won't know. A variant on the standard philosophical question ?if a tree falls in the forest and no one hears it, does it make a sound?? is raised here as an analogy to explain that not only does light need to ?hit something? to make it hot, but ?it?s also a question? of if, in the absence of a measurement, heat may not be a meaningful concept. It is an argument about the kind of thing that heat is. This analogy could be interpreted in a structure-mapping framework in that it maps elements from the secondary onto the primary; one could align the locker with the light, the slamming with the light hitting a finger, and the heat with the sound. But categorization highlights a very different aspect of this analogical 94 reasoning, namely the ontological goal of expressing the kind of thing that heat is. The analogy is not drawn for the purpose of comparing two items and making a projection, but to make a sophisticated claim about the nature of light and heat. An epistemological analogy is drawn in the following transcript. The two students are undergraduate quantum mechanics students working on a problem set together. They encounter one problem (determining ?J,? the total angular momentum) and have trouble making headway from first principles so they try to work backwards from the answer. Ben can kluge together numbers that are present in the problem to arrive at the answer, but the way in which he assimilates these numbers is nonsensical, as he notes in the transcript below (transcript 5, lines 65 ? 74). Ben:All right, look at this ? look at this. If you take all the positives and add them together, you get eight-ninths. Anselm:Oh, oh. Ben:You take the negative, you get one-ninth. Anselm: Yeah that?s ? Ben: But you?re mixing apples and oranges. It?s dumb! Anselm: Yeah that?s so messed up, yeah that?s not the answer. If I just ignore the fact that I?m in the three-halves one-half and I?m in the one-half one-half and I just add them all together? Here the assertion of ?you?re mixing apples and oranges? is clearly not a matter of structure-mapping, but categorization. The ?apples? are not aligned to a specific element present in the physics problem. Rather, ?apples and oranges? has come to represent a category of dissimilar things erroneously compared, and Ben?s statement is a categorical assertion of the type of thing that he was doing. This claim is not new. Glucksberg and Keysar (1990) argued that the interpretation of a metaphorical statement was a process of categorization. As a means of accounting for this theory of metaphor interpretation as categorization, it has been argued (Gibbs, 1992, Bowdle and Gentner, 1999) that 95 conventional metaphors, such as apples-and-oranges, are interpreted as categories, but that interpreting novel metaphors is structure-mapping. In accordance with Bowdle and Gentner?s research and the categorization theory of metaphor, the creation and assertion of the conventional metaphor ?you?re mixing apples and oranges? seems clearly an instance of categorization and not structure-mapping. However, I claim that categorical assertions are also made with novel analogies. Bowdle and Gentner (1999) have argued against that, at least in the interpretation of novel analogies, but perhaps generated novel analogies could be considered assertions of categorization. In the following transcript a novel analogy is used in a similar way to the ?apples and oranges? and the ?tree in a forest? conventional analogies. The base of the analogy is clearly novel, not well- understood, and invented on the fly, but its role in the analogy is no different from that of the conventional analogies. The elements of the base of the analogy do not clearly map onto elements in the target, and the claim posed by the analogy is not instantiated by projection but by categorization. Again, a categorization model of analogy is far more capable of understanding the role of the base than a structure-mapping model. The students in the previous transcript continue to work on the problem of total angular momentum (transcript 5, lines 15 ? 26). Ben believes that they should be able to determine the answer because they know the constituent angular momenta and have some background in adding these to find the total. Anselm argues that this does not necessarily mean they can solve this more complicated problem, and draws a novel analogy to explain himself, that of the problem first introduced above of the electric field around Bugs Bunny?s ears. Anselm?s analogy is to say that this problem of adding angular momenta is like finding the field around an oddly shaped object ? not because of any 96 similar structures (the charge and Bugs Bunny don?t correspond to any particular items in the angular momentum case) ? but because you cannot always find the answer to complex problems using knowledge about simple problems. Knowing the field of an electron doesn?t mean that you know the field around an oddly shaped object, like the ears of Bugs Bunny. In this analogy, the structure of the problem (calculating total angular momentum from components) is only very weakly similar to the structure in the Bugs Bunny scenario (determining the field around an oddly shaped object); the similarity, and thus the analogy, lies in the fact that they are a similar type of problem. Furthermore, the base here is created ?on the fly? ? the idea that we have a stored representation of Bugs Bunny as an odd shape for the electric field to take seems highly unlikely. Far more plausible is the spontaneous construction of an ad hoc category of things that are more complex than their simple parts. The analogy is not from a well- understood base to a poorly-understood target, but instead the base is constructed spontaneously to represent an ad hoc category ? that of problems you cannot solve from first principles ? and asserts membership in this category. In defense of structure- mapping, it could be argued that the elements being aligned were not the particular elements of the problem at hand (the charge, the Bunny, and the constituent angular momenta), but rather the problems themselves are elements in a larger structure. But such a claim would bring us back to the problem of representation. The Bugs Bunny analogy can be represented as a structure in itself, or as an element in a larger structure, and choosing which representation is the one to use is a problem that structure-mapping does not address. 97 Previous Claims of Analogy as Categorization The claim of analogy as a categorization phenomenon is not new. The greatest proponents of this theory are Glucksberg and Keysar (1990). Why have their arguments failed and what does this dissertation bring to bear that others have not? First, I argue that past claims are overwhelmingly with regard to the interpretation of analogies and the claim I am making is about the assertions made by a generated analogy. Interpreting analogies allows for a much more narrow range of representations than generating analogies does. Second, as noted by Gentner, Bowdle Wolff and Boronat (2001) the ?category-based approach is ?localist:? it assumes a metaphor conveys a categorical relation between a particular pair of terms. Thus this approach addresses single metaphors and not extended systems of metaphors.? As demonstrated above, I am not making ?localist? claims with regard to analogies. Rather, I will argue in the following chapter that analogies assert categories based on schemas: categories are defined only within a particular cognitive model, and this cognitive model carries with it a quite extended schema. Previous arguments for a categorization model of analogy used a far more classical model of categorization. The following section addresses a final phenomenological property of analogies ? one that is not particularly demonstrative of the categorization framework at first glance, but within a particular ontology of mind, together with a current understanding of categorization, is particularly revealing of the reasons why we use analogies and the cognitive work that they do and is strongly supportive of a categorization framework 98 Analogies as Negative Assertions In this final section on phenomenology, I demonstrate that analogies are asserted as an alternative to another way of understanding a particular phenomenon. In part, this is a definition of analogy that distinguishes analogy from other forms of similarity, but it is a definition that arose from the data. In observing what seemed to be analogies and an effort to understand the cognitive work that these insightful moments of analogy did for the students, it became clear that what I understood to be analogies are the statements of similarity that are an unexpected similarity. This is a matter of convention, but one that, as I will demonstrate in the following chapter, is a rather powerful convention that is consistent with a particular ontology of mind and understanding of student reasoning. Violations of expected schemas In Women, Fire and Dangerous Things, Lakoff (1987), who argues that our categories derive from and are defined within cognitive models, notes that one indication of cognitive models is the use the term ?but? ? as in, ?she?s a mother but she has a job.? Such a statement makes far more sense than ?she?s a mother but she doesn?t have a job? ? which sounds strange. He argues that, to understand these statements and why one sounds so strange, we must turn to the idea of the cognitive model. ?Mother? exists in a complex model of nurturance and work, and ?working mother? is defined relative to this model (Lakoff, 1987 p 80): A working mother is not simply a mother who happens to be working. The category working mother is defined in contrast to the stereotypical housewife- mother. The housewife=mother stereotype arises from a stereotypical view of nuturance, which is associated with the nurturance model. According to the stereotypical view, mothers who do not stay at home all day with their children 99 cannot properly nurture them. There is also a stereotypical view of work, according to which it is done away from the home, and housework and child- rearing don?t count. This is the stereotype that the bumper sticker ?Every Mother Is a Working Mother? is meant to counter. The housewife-mother stereotype is therefore defined relative to the nurturance model of motherhood. This may be obvious, but it is not a trivial fact. I mention this because the analogies that have been presented in this chapter all have this ?but? quality to them. As in, ?the cup is overturned but it doesn?t spill? ? which makes far more sense than ?the cup is overturned but it spills.? As Lakoff says, this may be obvious, but it is not trivial. In the following chapter I will explore why this is not trivial ? how it can inform us about cognitive structure and our cognitive models of the world, and then I will revisit this again in considering what it means for education. Here I present it as a final phenomenological property of analogies ? student generated analogies in science are ?defined in contrast? to expectations, just as ?working mother? is defined. Examples from student-generated analogies: Analogies as negative assertions The analogies presented in this chapter are as follows: ? an overturned cup of water does not spill like other overturned cups of water, but keeps the water inside, like a toy cat swung overhead in a basket (transcript II), ? density of an object enables/enhances the motion of charged particles as opposed to hampering it, just like a countertop lets water flow while a sponge doesn?t, or stepping stones must be closely spaced to allow you to step (transcript I), ? ?authenticity? is not a property of an activity, but is a more ?interactive? adjective ? one that is not solely an attribute of curriculum, but arises from the interaction of the student and community with that curriculum, just as worship is an activity that requires a practitioner and a community of practice (transcript 3) 100 ? dropping a beanbag is not like (at second glance) dropping a bat, but can be understood as dropping a leaf from a bus, or ? it is not like dropping a leaf from a bus, it is like dropping a rock from that bus (transcript 4), ? a quantum mechanics problem is not one to be solved from first principles, just like you could not use a simple field equation to find the field around Bugs Bunny?s ears (transcript 5), ? a rock is not just a container of heat but also gives off heat, like sinks not only hold water but also have a drain (transcript 6), ? light cannot be received at one frequency and given off in a different frequency, just as one cannot be received a quarter and turn it into dimes and nickels, or ? light can change from red to infrared, just as one can have a dollar?s worth of wealth and spend only fifty cents (transcript 6), ? in order to determine if light contains heat you must put your finger in the light, just like the question of sound in the absence of a listener (a door slams and no one hears it ? transcript 7), and ? numbers normally can be added together or multiplied unproblematically, but when these numbers mean something (as in a quantum mechanics problem) adding these numbers might be akin to mixing apples and oranges ? it doesn?t make sense (transcript 5). In each of these analogies, they are (perhaps implicitly) not only a claim of similarity ? the cup of water is like the cat in the basket ? but equally, if not more significantly, they are a claim of dissimilarity. They arise as contradictions to what is expected. Numbers 101 usually can be added unproblematically (of course, this is only true in a mathematics classroom and rarely, if ever, true when applied to life); overturned things usually spill; objects are usually seen as generators of energy or receivers of energy but not both ? not a tub with a drain; whether or not something happened is not usually contingent upon someone being there to observe it. The way in which this plays into a categorization framework will be explored in greater detail in the following chapter. For now, I just would like to note that this property of analogies is not explained by structure-mapping and other theories of analogies. When it is accounted for, it is added on in an ad hoc manner ? by assuming that context or goals is significant and needs to be accounted for ? but accounted for in a somehow distinct way (Gentner and Markman, 1997). In their model of analogy, this phenomenology is not inherent to the analogy, but part of the context. In the following chapter, I will argue that it is fundamental to analogy and to the role that analogy plays. Furthermore, it allows for a definition of analogy that distinguishes analogy from routine categorization and similarity. Conclusion This chapter, which details the similarities between student-generated analogies and properties of categorization, may seem to disregard the adage: ?Correlation does not imply causation.? Categorization and analogy are both related to similarity, so they should have some phenomena in common ? but that does not imply that they are the same thing, arise from the same cognitive mechanism. The following chapter is designed to address causation by introducing an ontology of mind that can account analogies as arising from the same cognitive mechanism as categorization ? the only distinction being 102 that analogies offer an alternative categorization to what is expected. The correlation between analogies and categorization are summarized below. Analogies that students spontaneously generate in science classrooms are often presented in multiples: analogies that are all members of a more general class of phenomena, in which the generated analogies are in agreement with one another, or analogies that are tweaks from one to the next, representing a class of phenomena that bear a family resemblance to one another. These analogies are often ?far transfer? analogies that bear little superficial resemblance to their target. They may be constructed on the fly as opposed to recalled from past experience. And the base of the analogy may have a variable representation that changes as the analogy is negotiated. These phenomenological properties of student-generated analogies reflect properties that are representative of categorization phenomena: categories have multiple members and are often related not by strict rules or similarity of features, but a family resemblance that links the various members of the category. Categories are represented by a category prototype, which can account for the prevalence of ?far transfer? analogies. They are not stored representations that are recalled, but rather are constructed in a flexible process. Gibbs, in his article refuting Glucksberg and Keysar?s (1990) theory of analogy as a categorization phenomenon, claims (Gibbs, 1992): Most metaphorical expressions instantiate, sometimes in spectacular ways, preexisting metaphorical mappings in long-term memory whereby knowledge from a target domain is partially understood in terms of a dissimilar source domain? Metaphors do not simply arise out of temporary, ad hoc categorization processes perhaps to meet particular communicative purposes. Instead, metaphor is a fundamental characteristic of how people categorize and makes (sic) sense of their experience. Verbal metaphors?reflect particular instantiations of metaphorical categorization schemes in long-term memory. 103 These claims take into account the systematicity of metaphor and polysemy (one word with multiple, related meanings) and are designed to address the more common metaphorical expressions and not spontaneously generated ones. However, I would like to argue that these claims cannot be extended to spontaneously generated analogies. In light of the above analogies from scientific discourse, such as Bugs Bunny, light-as-currency, and dropping rocks from buses, these claims of metaphorical expressions as ?preexisting metaphorical mappings? are clearly not true of analogies in general, and particularly not true of student-generated analogies in science, in which they are often investigating phenomena for which they have limited experience and hence no established metaphorical mapping. Perhaps this inconsistency between the findings from studies of metaphor and the study presented here of student-generated analogies in science is due to inappropriately conflating the two ? established metaphor and spontaneously generated analogy. Metaphors, such as the parallels between the ways in which we discuss arguments and the ways in which we discuss war, are ubiquitous in the English culture and apparently ?preexisting,? while a student inventing a language for discussing quantum mechanics or falling cups of water must be somehow distinct from using a common language to discuss arguments. However, if I conflate these here ? metaphorical expressions and student generated analogies ? it is because the literature is unclear on the division between metaphorical expressions that are pre-existing and those that are more akin to student- generated analogies in science. At best, the literature virtually defines analogy to be structure-mapping and puts metaphor on a distinct footing because of this definition ? but such a definition rules out many of the instances of analogy that are discussed here. This 104 does not negate the fact that metaphor and analogy are a fundamental characteristic of how people categorize and make sense of experience ? but such an idea need not imply that metaphors and analogies (that is, the mapping of two domains) and their associated categories (that is, the set of phenomena that are consistent with a particular analogy) are fixed representations. Instead, I will argue in the following chapter that what is stored in long-term memory are particular schemas that may be combined in any number of ways and give rise to what appear, at times, to be stable categories. In a purely phenomenological sense, the properties of analogies outlined above are consistent with properties of categorization. Categorization does not require that there be stored representations of concepts or categories that we recall, but rather that ?concepts originate in a highly flexible process that retrieves generic and episodic information from long-term memory to construct temporary constructs in working memory? (Barsalou 1987). In the following chapter, I will outline an ontology of mind that is consistent with the findings from categorization and can account for the analogies described here. 105 Chapter 5: The Ontology of Mind Introduction This chapter takes the properties of student-generated analogies in science that were detailed in the previous chapter and introduces a theory of mind that can account for these, explaining how a particular ontology of mind can begin to account for findings in categorization and details why these findings should be expected to apply to analogies. I begin with an introduction to the idea behind ?ontology of mind:? what are the things that researchers have attributed to the mind and what does research show to be the fundamental building blocks of thought? I first review research in cognitive science and education that treats the mind as ?having? representations for concepts, and then introduce challenges to this ontology of mind. I introduce an alternative to this ontology, in which smaller schemas are the things the mind ?has? and these building blocks are put together into larger models that are in turn used to construct representations for concepts. The consistency of this understanding of the mind with categorization and, in turn, analogies is then explored. History of Ontology of Mind and Description of the Chapter Perhaps drawing from an analogy to computers, concepts have long been treated in cognitive science and education as internal mental representations that are then acted on by computational processes. Such research would say that a student ?has? a concept or ?has? a misconception. This assumption of concepts as stable representations and its implications on the ontology of concepts in the mind has been called into question in the 106 last decade in several fields, most notably by a paradigm in education of situated cognition. Situated cognition claims that knowledge is intrinsically situated, ?being in part a product of the activity, context, and culture in which it is developed and used? (Brown, Collins and Duguid, 1989) and, as such, one cannot discuss what ?thing? a student knows ? the very ontology of knowledge as thing is what they call into question. Despite these concerns about mental representations, the most widely accepted and used model of analogy is Gentner?s 1983 structure-mapping theory, a theory that ascribes representations to concepts and then acts on these. But there are multiple ways in which we represent the concepts used in an analogy as demonstrated in the previous chapter. ?Money? can be pictured as a fluid kind of substance or a hard currency kind of substance. ?Apples and oranges? can refer to apples and oranges or to a more general category, just as ?bugs bunny?s electrically charged ears? can mean just that, or can mean a strange shape with an intractable solution. As such, mapping the structure of a concept in an analogy must first entail creating a representation that can be mapped, a process that structure-mapping does not explicate. If the mind does not have static, unitary representations for concepts, what is the ontology of mind? Alternative to the unitary ontology of mind that is inherent to many models of analogy is a manifold ontology, as expressed by schema theory, idealized cognitive models and phenomenological primitives. These theories have been employed in explaining the graded structure of categories. As an alternative to structure-mapping, I argue that categorization, in the modern, non-classical sense (arising from cognitive models), more effectively describes analogical assertions ? not only because of the phenomenological similarities between categorization and student-generated analogies, 107 but also because of the ontology of mind implicit in a categorization framework of analogy. This chapter is divided into two parts. In the first, a theoretical account and literature review, I will sketch the basic idea behind structure-mapping, highlighting the assumptions that it makes about the representation of concepts in mind ? assumptions of the ontology of mind. I will contrast these assumptions with concerns from cognitive science, linguistics and education that argue against stable, large-scale structures of mind, and detail the alternative theories that account for this manifold ontology. I will then in the second part turn to student-generated analogies in science and show how these theories, in particular phenomenological primitives and idealized cognitive models, are consistent with these analogies. Section 1: A theoretical account of the ontology of mind Structure-mapping As explained in the previous chapter, structure-mapping theory argues that interpreting an analogy involves both alignment and projection. The process is described in Bowdle and Gentner (1999): Structure-mapping theory assumes that interpreting a metaphor involves two interrelated mechanisms: alignment and projection. The alignments process operates in a local-to-global fashion to create a maximal structurally consistent match between two representations that observes one-to-one mapping and parallel connectivity (Falkenhainer, Forbus and Gentner, 1989). That is, each object of one representation can be placed in correspondence with at most one object of the other representation, and arguments of aligned relations are themselves aligned. A further constraint on the alignment process is systematicity: Alignments that form deeply interconnected structures, in which higher-order relations constrain lower-order relations, are preferred over less systematic sets of commonalities. Once a structurally consistent match between the target and base domains has been found, further predicates from the base that are connected to the common system can be projected to the target as candidate inferences. 108 The claims from this theory that I intend to highlight are the single representation of a structure that is derivative of the base, and one-to-one alignment of objects in that representation. In particular, this theory assumes that concepts have representations that are then operated on; in a sense, the base of the analogy is primary and the structure ? a structure ? ?belongs? to that base. The variability and the stability of this structure, the representation, are not explicitly addressed in the original theory, nor is it necessary to assume that the structure is a stable and invariant property of the base ? however, the associated computational model of structure-mapping, the Structure Mapping Engine (Falkenhainer, Forbus and Gentner, 1989) consistently presents these representations as unitary cognitive structures belonging to the base. But just as research from categorization reveals that the concept of a leap has no simple propositional structure and no unitary cognitive representation as a categorical construct, neither will ?leap? or other concepts have a single representation and structure when applied in an analogical construction. Defining the representation of a concept for mapping in a structure- mapping theory is not a simple act of recall as the theory implies ? it is not our concepts that have stored representations that we simply recall, but rather our schemas that do or do not apply to concepts. Failing to address this presumes either that there are stable, unitary representations or that the retrieval of one representation from the manifold that exist is not a crucial element to analogy ? both of these assumptions are challenged below, first in a review of the literature on variability of conceptual representation and then I turn to student-generated analogies and evidence against stable, unitary representations of concepts. 109 The arguments for variability in conceptual representations Research from psycholinguistics, education and categorization has identified manifold representations of concepts and argued that when concepts are manifested as singular, stable structures this does not imply a unitary structure to concepts in the mind. These findings are further detailed below. Psycholinguistics Recent psycholinguistic theory has suggested that the mental lexicon, instead of being organized in a dictionary-style, is far more like a thesaurus. That is to say, the way our minds represent words is not so much as obeying rigid definitions with propositional structure, but rather the meaning of one word is tied to a network of related words ? words that have appeared in similar contexts, words that have appeared in context with that word, and words that have related meanings. Computationally generated lexical networks have been developed to represent the lexical network of the English language (one example is the well-known Wordnet, by Fellbaum, 1998). These thesaurus-like structures link words in definitions into a network using various algorithms. Gaume et al. (2002), building on categorization research that they summarize as establishing the ?conceptual flexibility? as opposed to ?rigid and discontinuous categories,? argue that words themselves constitute categories and contend that these lexical networks weave a ?mental lexicon distributed around metaphoric poles.? Amin (2001), in a cognitive linguistics study of heat, makes a similar claim about certain conceptualizations ?as dynamic constructions at the moment of use,? finding that ?a stable assignment for the ontology of ?heat? is absent from the layperson?s core understanding, but rather emerges 110 in specific explanatory contexts.? (p 38) Quinn (1987) has reported similar findings with regard to the concept of marriage as having conceptual flexibility: Quinn (1987) has found, in studying conversations about marriage in minute detail, that each spouse in a marriage has multiple, and often contradictory, understandings of what marriage is. But it is common in a discussion of marriage for a spouse to shift mid-sentence to a different understanding which is inconsistent with the one they sentence started out with. (Lakoff, 1987 p 215) As with claims from situated cognition, these findings counter the relatively frequent assumption in cognitive science that there are single, fixed mental representations of concepts. In drawing analogies between a base and target, assuming a single representation of that base will fall short of explaining the power and feat of the analogical mapping, as demonstrated in the transcripts presented in the previous chapter. Students are able to shift representation of concepts used in an analogy and choose to represent a concept as an epistemological (as with ?Bugs Bunny? in transcript 5), ontological (as with ?authenticity? in transcript 3) or mechanistic (as with ?ice skating? in transcript 1) statement. Categorization, in which categories arise from cognitive models, as I explain below, allows for this flexibility and accounts for the nature of analogical reasoning that students display. Education In addressing student difficulties in physics, several researchers refer to common ?misconceptions? that students have and propose curriculum to address these (e.g., Doran, 1972; Caramazza, McCloskey and Green, 1981; Griffiths and Preston, 1992; Brown, 1992). Implicit in these statements, and their associated curriculum, is that there are stable, consistent conceptions students have that educators can find and change. However, Taber, in a study of students? conceptions of bonding in chemistry (Taber, 111 2000), found that students employed different representations to the same concept on different occasions. He reports that the idea that students cognitively ascribe a particular structure to concepts is a reflection of ?the researchers? conceptualizations ? explicit or tacit ? about the nature of cognitive structure.? This claim echoes Barsalou?s criticism of the paradigm in categorization research that aimed to define the structure that students ascribe to categories (Barsalou, 1987): When investigators use linguistic analysis to determine prototypes, definitions, and idealized cognitive models, they appear to assume that there are invariant concepts in long-term memory that need to be fully characterized. Similar to Barsalou?s findings (if you look for variability in representations of categories you will find it) Taber found that the idea that students hold a particular conception of a scientific phenomenon is flawed. An individual learner can simultaneously ?hold in cognitive structure several alternative stable and coherent explanatory schemes that are applied to the same concept area? (Taber, 2000). A theory of mind to account for these findings involves schema theory, detailed below. I first return to the evidence from categorization research that tells a similar story of variability, and then introduce schema theory, which can account for these findings and can account for the graded structure of categories. Categorization Rosch (1973) established that human categories were not, as one might assume, simple ?containers? of which an exemplar was either a member or not. Rather, categories exhibit a graded structure with some members being judged more prototypical of the category than others, and a gradience in membership, so that the distinction between a category member and a non-member is not clear. Continued research by Rosch and 112 others was designed to determine the structure of these categories and the origins of that structure. Barsalou?s initial research on categorization looked at ad hoc categories (such as ?foods not to eat on a diet? or ?items to take from your house in a fire?) and showed that these categories, though certainly not stable categories that are represented cognitively prior to their construction, still possessed the graded structure found in ?common? categories. His continued research looked into the stability of this graded structure (Barsalou, 1987). He asked participants to judge the typicality of category members from their own point of view and the point of view of others (such as a professor?s point of view) and analyzed between- and within-subject reliability of categorizational structure. The findings point to significant variability in graded structure: participants were able to judge the typicality from others? points of view (occasionally with stunning accuracy). Additionally, the within-subject judgments of typicality varied (with moderately typical category exemplars changing rating the most). Graded structure, Barsalou concludes, is ?a highly flexible and unstable phenomenon.? Context, linguistic context, point of view, and other factors affect the typicality assigned to category exemplars. Surely, he argues, people do not possess representations in long- term memory of how a professor would assign structure to the category of dinner foods. The implication on the structure of categories, Barsalou argues, is that ?rather than being retrieved as static units from memory to represent categories, concepts originate in a highly flexible process that retrieves generic and episodic information from long-term memory to construct temporary constructs in working memory? (Barsalou 1987). This is not meant to imply that there is not stable knowledge in long term memory, but rather that the concepts in working memory ? the ideas that are pondered, 113 discussed, articulated and reasoned with ? are temporary constructs and, as such, sensitive to context and goals and inherently unstable. Furthermore, prototypes of categories are not stable properties of categories ? these are not the elements that are stored in mind and organize categorization. They arise from cognitive processes on more stable units. But what are the stable units that minds have, then? Structures in a manifold ontology of mind Resources Stemming from findings regarding the variability of reasoning in science, Hammer (2004) has argued against a research paradigm in science education that focuses on student misconceptions and its implicit assumptions on the nature of concepts and mind. What sorts of things do we attribute to students? minds? It has become conventional to speak and think in terms of conceptions, na?ve theories, and stages of development. These are all attributions of stable properties, and they account well for patterns that can occur in student reasoning. They do not account well, however, for the variability and multiple patterns illustrated [elsewhere]. As an alternative to the unitary conception of mind, he offers what is termed the ?resource model? as a more fruitful ontology of mind with multiple, fine-grained cognitive resources that are or not activated. Different conceptions of marriage, as mentioned above, could be considered different resources for understanding this concept that are activated at different moments. This is not to say that students cannot or should not have a robust, stable representation of a particular concept, but rather, as noted by Hammer: ?Ontology need not recapitulate phenomenology? The cognitive objects we 114 attribute to minds need not align closely with the ideas and behaviors we hope students to transfer.? (Hammer, et al 2004). Idealized Cognitive Models, Schemas, and P-prims Lakoff (1987) has proposed that categories are derivative of idealized cognitive models of the world (ICMs), ?which van be viewed as ?theories? of some subject matter.? (Lakoff, 1987 p. 45). These ?theories? can be parsed into various schemas or short ?scripts? that we have about the world and the way it works: event schemas that are abstracted from our experience of certain events, image schemas that provide structure for conceptualizations ? ?schemas of intermediate abstractions [between mental images in abstract propositions] that are readily imagined? (Palmer, 1996 p. 66) ? and proposition schemas: abstractions that act as models of thought and behavior and specify ?concepts and the relations which hold among them.? (Quinn 1987) Schema theory holds that we possess a pattern of associations in our mind that lead to locally coherent ways of understanding and negotiating our world. As described by Rumelhart (1981), schemas are the fundamental elements upon which all information processing depends. Schema[s] are employed in the process of interpreting sensory data, ? I retrieving information from memory, in organizing actions, in determining goalas, ? in allocating resources, and generally in guiding the flow of processing in the system?[Schemas represent knowledge] about ? objects, situations, events, sequences of events, actions, and sequences of actions. And schemas are distinguished from the more generic ?models? in Redish (2003, p 13): I follow the notation of D?Andrade and call such a pattern a schema if it is a ?bounded, distinct, unitary representation? that is not too large to hold in working memory. I call a pattern a (mental) model if it consists of ?an interrelated set of elements which fit together to represent something. Typically one uses a model to reason with or calculate from by mentally manipulating the parts of the model in order to solve some problem.? (D?Andrade, 1995 p 151) 115 This is to say: what we do have in our minds are short scripts, sequences, or stories that can be combined to create models. These are ?bounded, distinct [and] unitary,? unlike the phenomena that they may describe. Taber (2000) noted that an individual learner can simultaneously ?hold in cognitive structure several alternative stable and coherent explanatory schemes that are applied to the same concept area,? namely in the concept of bonding; these coherent explanatory schemes are what I mean by a locally coherent structure ? bounded, distinct, and unitary scripts for understanding bonding ? while bonding is understood with a manifold set of schemas. (Of course, part of science involves reconciling competing schemas and placing them within a larger explanatory framework that accounts for both ? it is in this that Hammer (2004) notes, ?the cognitive objects we attribute to minds need not align closely with the ideas and behaviors we hope students to transfer.?) It is only within our schemas that categories are defined and meaningful. As noted in the literature review, the question ?is the Pope a bachelor?? is a confusing question. By all definitions of ?bachelor? the answer is yes, but no one would ever refer to the Pope as a bachelor. Lakoff explains this paradox with an appeal to cognitive models: ?bachelor? is defined and meaningful only within a cognitive model (a sets of schemas) of society that has marriage and the schemas associated with marriage ? and these schemas that are activated do not take into account our schemas involving clergy. Therefore this category ? bachelors ? becomes less meaningful and exhibits a graded structure to the degree that the schema in which it is defined does not apply (as in the case of the Pope). And prototypes of our categories arise from the concretization of these 116 cognitive models. It is not the exemplars that organize our categories, but the schemas and compilations of those schemas into larger cognitive models that organize (and at times construct) exemplars into categories. When discussing prototypes in this dissertation I am not referring to static exemplars around which our categories are organized, but ad hoc constructions and recollections that are organized by the schemas, cognitive models and resources that are activated. This differs greatly from the representation of concepts from structure mapping and the related computational model. For even if the model took into account a variability of representations, the model still attributes these representations as stored properties of the base and not more abstract, general schemas. 1 In the model of analogies as assertions of categorization, then, there is implicitly some underlying schema involved. In physics education research, a set of simple, 1 For example, noting the lack of variability for concepts described in the Structure Mapping Engine, the following suggestion for incorporating multiple representations is introduced (Falkenhainer, Forbus and Gentner, 1989, p 39): The SME algorithm is of necessity sensitive to the detailed form of the representation, since we are forbidding domain-specific inference in the matching process. Existing Al systems rarely have more than one or two distinct ways to describe any particular situation or theory. But as our programs grow more complex (or as we consider modeling the range and depth of human knowledge) the number of structurally distinct representations for the same situation is likely to increase. For example, a story might be represented at the highest level by a simple classification (GREEK-TRAGEDY) at an intermediate level by relationships involving the major characters (i.e., (CAUSE (MELTING WAX) FALL)),and at the lowest level by something like conceptual dependencies. An engineer's knowledge of a calculator might include its functional description, the algorithms it uses, and the axioms of arithmetic expressed in set theory. Unless there is some window of overlap between the levels of description for base and target, no analogy will be found. 117 primitive schemas that students use has been identified. These, as noted in chapter two, are phenomenological primitives. From chapter two (p. 32, this document), They are ?the intuitive equivalent of physics laws; they may explain other phenomena, but are not themselves explained with the knowledge system.? As defined by diSessa, p-prims are ?cued to an active state on the basis of perceived configurations, which are themselves previously activated knowledge structures.? In this way p-prims are elements within larger models. P-prims ?often originate as minimal abstractions of common phenomena,? and are ?nearly minimal memory elements, evoked as a whole.? By way of example, consider one class of p-prims: the ?constraint cluster.? This class includes bouncing, supporting, guiding, clamping, and carrying. These p-prims are not fundamental for a physicist (all can be explained in terms of forces) but are often elicited in conversations with students as explanations for physical behavior. The p-prims have a ?schematization? such as, for the ?supporting? p-prim, ??strong? or stable underlying object keeps overlaying and touching object in place.? (diSessa, 1993 p. 216) Many of the analogies that students express can be shown to have their origin in phenomenological primitives. Below, I will show that the analogies presented in chapter two for their phenomenological similarity to categorization can be understood by this ontology of mind: they are based in particular schemas and the role of the analogy is to move the target of the analogy from one locally coherent structure to another. First I would like to address a point raised in the previous chapter: analogies as negative assertions, and the distinction between similarity and analogy. Interlude: A distinction between similarity and analogy The conflation of similarity and analogy in past definitions If this is how the mind works ? it has stored schemas that become activated and put together in a variety of ways, and these schemas are responsible for our categories, and, as Lakoff (1987) noted, everything is an act of categorization: Every time we see something as a kind of thing, for example, a tree, we are categorizing. Whenever we reason about kinds of things ? chairs, nations, illnesses, emotions, any kind of thing at all ? we are employing categories. 118 Whenever we intentionally perform any kind of action, say something as mundane as writing with a pencil, hammering with a hammer, or ironing clothes, we are using categories. then perhaps structure mapping is just a way of detecting a schema that applies. That is to say, structure-mapping involves abstracting a structure from the base that you then map onto the target, and, given that the mind has stored schemas, perhaps ?structure? is simply another word for ?schema.? The schema is the structure and this is mapped onto a new scenario in what we see as analogy, and then the only piece lacking from the structure-mapping story is how that particular schema is arrived at, given the manifold that exist. But if this is the case, then every act of categorization becomes an act of analogy, as Hofstader (2003, p 506) believes to be the case: The triggering of prior mental categories by some kind of input ? whether sensory or more abstract ? is, I insist, an act of analogy-making. Why is this? Because whenever a set of incoming stimuli activates one or more mental categories, some amount of slippage must occur (no instance of a category ever being precisely identical to a prior instance). Categories are quintessentially fluid entities; they adapt to a set of incoming stimuli and try to align themselves with it. The process of inexact matching between prior categories and new things being perceived (whether those ? things? are physical objects or bite-size events or grand sagas) is analogy-making par excellence. How could anyone deny this? After all, it is the mental mapping onto each other of two entities ? one old and sound asleep in the recess of long-term memory, the other new and gaily dancing on the mind?s center stage ? that in fact differ from each other in a myriad of ways. Consider the diagram below, first presented to me by Redish (research group meeting, 2004) and constructed by Edward Adelson. When participants are shown this diagram and asked which square is darker, A or B, everyone will claim that A is the darker square. 119 Fig. 5.1 In fact, the squares are the same shade ? but even knowing this it is hard (if not impossible) to convince your mind otherwise. We cannot help but run the ?schema? that helps us judge the relative brightness of objects. And so, in a sense, we are mapping all of our prior experiences with intensity, shades and shadows onto this new experience. According to structure mapping, this is analogy ? we have mapped the structure of prior experience (things in the shade are lighter than they appear) onto this new experience (B is in the shade, it must be lighter); according to Lakoff, this is categorization (we are using a cognitive model and placing this picture into that model); according to Hofstadter, these ? categorization and analogy ? are one and the same. A similar claim can be made of the students in transcript 2 that believe this new cup of water will spill: they are assuming that this cup of water is like all other cups of water ? it will spill when overturned. They are mapping a structure or schema involving cups of water onto this new cup of water. But there is something that feels different about Miranda claiming that 120 a cup of water is like a toy cat in a basket and the other students who are implicitly mapping their prior experience with cups and water onto this instance of a cup and water. This distinction between analogy and more ?knee-jerk? categorization/ identification of schema is addressed by diSessa (1993), in studying the ?Montessori bell conundrum.? In this problem, students are presented with bells made of the same material, same length, same height, but varying widths. Almost without exception students predict (erroneously) that the thicker bells will have a lower pitch. DiSessa reports: Although most subjects were ready with analogies ? church bells compared with jingle bells, xylophones, musical instruments of various sizes ? I was struck that some initially could not produce any example of the phenomenon they identified to be at the root of the situation. This, along with the rapidity and expressed certainty of responses, heightened my confidence that a p-prim (or several) was at stake rather than analogy. (diSessa, 1993) That is, students are able to make a prediction for the Montessori-bell conundrum without any explicit reference to an analogous case. Many students are able to construct, post- hoc, an analogy to explain their reasoning, but some cannot ? suggesting that the prediction for these bells was not made with any explicit analogical reasoning between this set of bells and other sets of bells or instruments. DiSessa, accordingly, distinguishes this automatic assumption/prediction from analogy. This distinction between analogy and p-prim that diSessa makes is not consistent with structure-mapping or other accounts of analogy: while diSessa claims that a p-prim is not an instance of analogy, Gentner?s description of structure-mapping and Hofstadter?s account of the ubiquity of analogy construct a definition of analogy in which any kind of similarity is analogy. And perhaps it is quite fruitful not to distinguish instances of p-prims and schemas from analogy. This is Hofstadter?s approach, and 121 surely understanding the more routine acts of categorization ? how we recognize an ?a? in handwriting that we have never seen before, for example ? can shed light on how we make the more creative feats of imagining a cup of water to be like a toy cat in a basket. I would like to distinguish the more creative aspects of analogy, those that are powerful for their ability to shift from one locally coherent structure to another, from the more routine kinds of activities that our minds undertake automatically and without cognitive effort. This is a piece that is missing from structure-mapping and is acknowledged by its authors, who note that the Structure Mapping Engine (a computational model of structure mapping) finds literal similarity to be the best possible match when determining the soundness of an analogy: when comparing relational structures and disregarding surface features, the literally similar structures will, naturally, be the strongest possible match (Gentner, 1989). Or, as Gentner and Markman note (1997, p 48), ? this contrast between analogy and literal similarity is in fact a continuum, not a dichotomy. Yet it is an important continuum psychologically, because overall similarity comparisons are far easier to notice and map than analogical comparisons, especially for novices.? However, other researchers have found criticism in this continuum account of analogy, in particular the lack of attention to goals and context. As Holyoak (1985, p 74-75) notes, ?even objects that Gentner would term ?literally similar? can be analogically related if a goal is apparent.? Commenting on this criticism, Gentner notes ?since this is essentially a question of terminology, it may be undecidable? (Gentner, 1989 p 220). 122 A proposed definition of analogy as a change of schema It is a question of terminology and a matter of choice as to whether or not this is what we mean by analogy and if we would like analogy to exist on a continuum from similarity or be somehow distinct, but I would like to focus on those analogies that take us from one schema to another and take deliberate cognitive effort, and contrast those with more routine categorization that happens cognitively automatically. Both are acts of categorization, but one, analogy, I will use to mean a recategorization. In this way, analogy is so powerful because of what Koestler has identified as the ?essence of creativity:? being able to view a situation or an object from two different frames of reference, or two ?unrelated matrices of thought? (Koestler, 1964). Or, as Chi (1997) clarifies, ?the essence of creativity is? re-representing an entity or a situation from one ?ontological? tree of concepts and categories to another ontological tree of concepts and categories.? This recategorization is more profound than considering a person to be both a daughter and a sister and a chef ? that is, it is not simply choosing one of a myriad of schemas that apply to a phenomenon, but instead invokes a schema that is at odds with the alternative category. For example, considering a cup of water to be unlike most cups of water that do spill, and more like a toy cat in a basket that doesn?t. Using a dial ammeter to measure current, undergraduate students in my Physics 115 course measured the current coming from the battery in the following circuits: 123 Fig. 5.2: Circuit set-ups for measuring current from battery Slightly more current leaves the battery for the circuit on the left. Though the measurements were initially taken for another purpose, I later referred to them as a counter-argument to a student?s claim that the battery always puts out the same amount of current. But the students claimed ? erroneously ? that the ammeter readings gave the same value. It?s understandable ? the dials are difficult to read precisely and students often round ? but that alone doesn?t explain it, as students will often argue over insignificant differences in readings and each lab group reported the same findings: the ammeters read the same value for the current leaving the battery. Only one student recorded ?100+? and ?100?? because of the discrepancy in the ammeter readings. Perhaps the students had expectations about what these numbers should be ? but this expectation did not come from their knowledge of circuits or experience with ammeters (none had extensive experience with either), but from experiences with phenomena in which the output from the source is not mitigated by the consumer ? like rain, perhaps. This can also help explain why students, when handed a bulb, battery and wire, often first try to light the bulb in this manner: 124 Fig. 5.3: Typical arrangement tried by students The battery is a source of energy and the light is a consumer of that energy, and the students assume that, as with every other source of energy, you need a path from that source to the consumer. You rarely (if ever) need a path back. The students? attempts make sense ? they are matching a pattern they have observed before with other sources of energy and mapping it onto a new case. But is this analogy? Again, Hofstadter (2002) argues that it is, and structure mapping would say that either this is analogy, or that structure mapping requires an explicit reference to the base ? a reasonable argument but also somewhat post hoc. I argue that this is not analogy by definition, because in the absence of such a definition we risk turning everything into analogy. Analogy is a deliberate cognitive step that involves a negative assertion, claiming that this source of energy (the battery) is not like other sources of energy. In this chapter, I am providing the sketch of an underlying cognitive mechanism to account for the phenomenology described in the previous chapter. What are the pieces of mind that can explain student-generated analogies? The themes of findings on the ontology of mind that will be revisited below in the context of student-generated analogies is as follows: if anything is stably stored in the mind in invariant ?chunks? it is not large-scale theories or concepts, but much smaller scripts and stories that provide a 125 kind of ?alphabet? of sorts for constructing theories. This suggests that while certain schemas may be associated with a particular analogical base, it is more accurate to consider the schema as the fundamental cognitive unit. Or, structure mapping implies that an analogical base ?has? ? rather objectively ? a particular structure. Rather, the theories of schemas, p-prims and ICMs suggest that a particular schema or p-prim is primary and this schema becomes concrete by constructing a base. The base is a representation of a particular schema and is understood and interpreted within that schema. Beginning, again, with Miranda?s analogy of the toy cat in a basket, below I will outline the schemas associated with the analogies that students generate and argue that these analogies are particularly relevant (or prototypical) of that schema. Section 2: The base of generated analogies as representations of a schema The analogies presented in the previous chapter for the phenomenological similarities between categorization and student-generated analogies, are presented and analyzed below for the schema from which they derive. The categorical assertions that the analogies make are consistent with these schemas, and the ontology of mind implicit in a categorization framework of analogy is consistent with findings outlined above. Schemas and p-prims in the cup/water analogies The transcript from a 5 th grade class, discussing what happens to a cup of water as it falls, was first introduced for the phenomenological evidence in support of categorization; in the exchange surrounding this analogy there are multiple analogies presented, the analogy that is first presented is ?far? transfer, and it is presented in opposition to the schema other students implicitly apply. I present these analogies in this 126 chapter to make an argument for the reasoning behind these analogies, for the schema in which they are based and how the analogies may be viewed as prototypical or particularly characteristic of that schema. Having been asked to predict what will happen when an overturned cup of water is dropped from a cookie sheet, a student predicts that the water will not fall out until it hits the ground and uses the analogy to a toy cat being swung overhead to explain her prediction (transcript 2, lines 13 ? 26), claiming ?I pull it down and it stays in the back [motions that the cat is up at the top] until I stop and then it comes out.? Past models of analogy argue for a one-to-one alignment of objects in the target and base of the analogy that, once made, allow for candidate inferences to be drawn (in this case the candidate inference is that this cup will not spill). Instead, I posit that the function of Miranda?s analogy was, first, to identify a different story ? one about swinging baskets that, when overturned, don?t spill ? and used this event schema to reclassify this cup as a different kind of thing. It isn?t like most overturned cups, she argues ? it belongs to a class of phenomena that is typified by an overturned, swinging basket. By understanding the schema Miranda is employing, this analogy is not so much an instance of ?far transfer? but instead prototypical of a particular event schema with which Miranda is familiar. The very idea of ?far transfer? ? which has been the focus of many research studies ? may not be the most meaningful concept in studying learning. Far more relevant in drawing analogies is recognizing that the base of an analogy is the concretization of an appropriate schema, and that base is a prototype ? that is, the spontaneous construction of a representation for that schema. The cat/basket analogy is like an airport hub: we arrive here before we arrive at nearby towns ? it?s an entry point 127 to a certain area. Our minds don?t detect similarity solely by matching features. Just as travel distance is measured along roads from airports, and not as the crow flies, it does not make sense to discuss ?near? and ?far? analogies when you are restricted to moving through the cognitive map along particular schemas and via particular patterns of activations. You arrive at the airport before you arrive at closer towns ? it takes less time for me to get from DC to Seattle than to get to Mazama, a mountain town east of Seattle. Schema The theoretical and empirical support for this interpretation of Miranda?s analogy comes respectively from research in physics education on phenomenological primitives (p-prims) and two phenomena surrounding this analogy: Miranda?s gesture during her explanation, and Miranda?s choice of base in the analogy. P-prims ?often originate as minimal abstractions of common phenomena,? and are ?nearly minimal memory elements, evoked as a whole? (diSessa, 1993). By way of example, consider a particularly relevant class of p-prims (relevant to the transcript above): the ?constraint cluster.? This class includes bouncing, supporting, guiding, clamping, and carrying. These p-prims are not fundamental for a physicist (all can be explained in terms of forces) but are often elicited in conversations with students as explanations for physical behavior. The p-prims have a ?schematization? such as, for the ?supporting? p-prim, ??strong? or stable underlying object keeps overlaying and touching object in place.? (diSessa, 2003 p 216) Miranda is employing the ?carrying? p-prim (and its associated schematization) together with noting the upside-down container. Her gestures, in particular, are indicative of this p-prim. With her explanation she begins by miming holding a right- 128 side-up basket, arm at side, and then swung overhead. She repeats this motion again with each successive explanation: the toy cat is held by a right-side-up basket, swung overhead, and held in the bottom of the basket as she pulls down. When she stops pulling (that is to say, she stops the ?carrying? part of her actions) the cat falls out. Prototype Prototypes are, as defined by Rosch, the first members of a category that you recall, are quickly recognized as members of that category, and can be used to generalize about other category members. With respect to the ontology of mind presented in this chapter, prototypes are not primary, nor do they serve as mental representations of categories; rather, schemas are primary and may be put together together to create a larger scenario ? such as the falling cup of water ? from these schemas we construct categories, and it is through the concretization of these schemas and categories that we arrive at prototypes. They are constructed on the fly from the schema (or bundle of schemas) that are activated. In terms of understanding Miranda?s analogy, it seems likely that the base of the analogy (the cat/basket) is prototypical (in that it is drawn first, used to generalize, and easy to learn). Miranda has a set of schemas that have been activated ? perhaps carrying and overturned (and even, perhaps, things that are surprising ? one can imagine Miranda thinking: ?He wouldn?t ask this question unless the answer was something interesting and weird.?) ? and she makes these schemas concrete and, hence, relatively stable by the construction and assertion of this base, which is latched onto not because of its similarity to the target of the analogy but because it is the most immediate and unproblematic representation of these activated schemas. Miranda, in fact, has experience with more ?similar? members of this category but constructs an analogy to the 129 cat/basket first. She refers to the cat/basket as a ?rollercoaster? game but does not use a rollercoaster as her analogy, and then claims that the cup of water is like an instance when she dropped a cup of water in her bathtub (transcript 2, lines 55 ? 61). As noted in the chapter on the phenomenology, previous models of analogy in which objects are placed in a one-to-one alignment would predict that Miranda should first draw the bathtub analogy: the features are closer and more easily mapped. In a categorization model in which the category emerges from the associated schema, the swinging basket is naturally a more readily available analogy, as it is, for Miranda, a more prototypical/accessible a case for the schema associated with carrying things upside-down. Cups with water are often in a different schema ? the water frequently spills from overturned cups ? while the toy cat rarely falls from an overturned basket in this scenario. With the rollercoaster scenario ?carrying? would be a less relevant p-prim ? ?guiding? as a p-prim would be more applicable (and, indeed, has been identified as the p-prim used in explaining the motion of a train on its tracks). Multiple analogies As the conversation continues, students in this classroom present multiple analogies relating to the toy cat in the basket to a bucket of water, tossing Halloween candy, throwing a hat with dice inside, and a basket of Easter candy (transcript 2, lines 137, 181, 184, and 201). Not all of the students that introduce these analogies agree with Miranda that the water will stay in the cup ? however, they are able to understand the schema that Miranda has identified and are able to identify other members of the categories constructed by this schema ? ones, perhaps, more prototypical for them and more obvious members of a category associated with the ?carrying? p-prim (the dice are 130 carried by the hat and the water carried by the bucket). In this way, the above listing of analogies can be seen as ?fleshing out? the category in order to better categorize the novel water-cup system. A recategorization of the target A final claim I would like to make regarding this transcript is that the students are recategorizing the cup/water with the analogies they generate ? an idea first introduced in chapter 4 and revisited here for the ontological and theoretical aspects of this claim. This requires that the cup/water was originally an element in a different schema, and the role of the analogy is not merely to map a new schema onto this existing problem, but to change the schema in which it is understood and defined. Why is this distinction important? First, it acknowledges that we understand and categorize objects and phenomena by an identification with a schema that we have in mind and that it is impossible not to do this: this is just how the mind works. If structure-mapping is this, the identification of a schema to apply to a given scenario, then, as noted above, everything is structure-mapping and it is not a reasonable account of analogy as distinct from routine similarity and categorization. Second, it acknowledges that the schema (or structure or p-prim) is primary: we schematize and categorize without awareness or careful consideration, but automatically. If schemas are primary, it makes sense to think of the base of an analogy as representing a member of a category that the schema defines and not the other way around. That is, we do not move from the particular to the abstract when generating an analogy (though this may be a more reasonable idea in interpreting an analogy). We search for an analogy to explain, concretize and help us understand a schema we have 131 already identified. Third, we only search for this analogy when the schema is at odds with a more expected schema ? if the schema is expected, as with water spilling from a cup, it is often so obvious as to be invisible. (One can imagine that most students in the class are at a loss as to what to explain when asked what they think will happen to the overturned cup of water.) This is consistent with diSessa?s (1993) set of heuristics for identifying p-prims. Foremost among these is the ?principle of obviousness.? As diSessa state (p 121): The familiarity and unproblematic nature of some physical events needs explanation. In the present context, this usually means they need a p-prim to attach to them. In general, p-prims establish abstract classes of unproblematic happenings. This is the opposite of misconceptions research strategy, which never analyzes ?correct? intuitions. The principle of obviousness gains explanatory power in conjunction with the principle of invariance; having understood p-prims underlying common events, we may be able to understand subjects? reactions to uncommon events using those same p-prims. Just as misconceptions research does not analyze ?correct? intuitions, neither does most analogy research, in particular structure-mapping, address the incredible ubiquity of ?structure mapping? in everyday occurrences that we do not consider to be analogy. There is an obvious and expected answer to ?what will happen to the water when you drop the cup.? Most students assume that the water will spill and splash ? that they do not explain this further is evidence that a p-prim is at play, in that it seems ?obvious? and ?impenetrable.? Even Miranda, who predicts the water will stay in the cup, expresses surprise and fascination when the experiment is performed and the water stays in. Indeed, even to a trained physicist the result is eye-catching. But the brain has a way of understanding this, has a schema in place for this, and the role of the analogy is to 132 identify an alternative schema and place this cup of water in a category associated with that schema. The Beanbag Analogies The analogies presented in this section were introduced in the last chapter for the phenomenological property that the base of the analogies are often constructed or invented, rather than recalled. Here I argue that the three students each are operating under three different schemas. As such, the analogies they choose differ and are prototypical of the schema they are employing. In the following transcript from a third grade class, the teacher has told the students that she is going to run while holding a beanbag that she wants to drop onto an ?X? marked on the classroom floor. Should she drop the beanbag before, when, or after she reaches the ?X?? Adam, one of the first students to speak, addresses Newton?s Laws. The teacher (Trisha Kagey) asks for explanation. The following statements incite multiple spontaneous analogies, comparing the beanbag to a bike, a bat, a leaf, a rock and a feather (transcript 3, lines 35 ? 40, 55 ? 73, 83 ? 87, 154 ? 159 and 188 ? 190): Adam: ? if you?re riding your bike, um ? it?s in motion. And you?re going to keep going until you get stopped by like ? um, a rock or something ? or going uphill? Connor: I would think the bean bag would ? might fall behind where you want it to fall because when I put ? when I played baseball ? they always said don?t throw the bat because it might hit the catcher and not one of the um person because we?re using metal bats, and ? so we drop it, you drop it and then you ? . Well, when I drop it, it usually swings backwards; it wouldn?t be behind the plate instead of the front of the plate? Teacher: Why do you think it fell behind? Connor: Well actually it didn?t mostly. It got on the side or in front because ? well because you?re supposed to drop it because you don?t need a bat while you?re running the bases. Once you drop it, I?m just 133 thinking also, what Adam is ? well a bus ? well if you were on a bus and you had uh, this little leaf that you found, and the window was open, and you drop it, it will go ? it?ll be going backwards? Lauren: Because I think that?s cause ? you?re talking about a leaf that?s falling? That?s because the ? it?s sort of ? the bus is going back, so it?s making like the air move. And the leaves are really, really light, so the reason they are going backward is because ? Um, well it?s going so fast? Connor:What if you did it with a rock? The same thing will probably happen with a rock. Because you are probably like a bus, that you make the air come ? Kamran:? A rock is different, a rock has ? it?s also like, it?s solid, but it?s not that a leaf isn?t solid, or a feather isn?t solid. A feather ? but you have to ? it?s very small, and it?s very like thin, so you kind of say like solid. But anything hollow, like if you have a paper box? Kamran: Yeah, because the weight pulls it right down. If a tree ? it?s heavy, and it?s heavier than all the leaves it has, so the leaves will make it fly ? fly here. And the tree, it will just go down. In this segment, the beanbag drop is compared to a bike, a baseball bat, a leaf and a rock. The person doing the running drop is compared to the bike, the bus and a person. These items are not chosen arbitrarily, but because of a particular schema the students have. Schema 1: A Newtonian Schema Before discussing his analogy, Adam says ?it will instead of going straight down, it will go um ? it will go in front because it?s not stopped yet. But when it hits the ground, because there is friction on the ground ? there is more friction on the ground than in the air it will get stopped and land somewhere around there (the X).? It is only after the teacher asks Adam to explain it more clearly (?like you?re explaining it to a Kindergartener?) that Adam, after some pause, comes up with his analogy. This schema, which is consistent with Newton?s Laws (objects in motion stay in motion), is not one 134 with many members that would be well known to a young student ? when walking, swimming, or pushing something, for example, you naturally slow down. A prototype is not a category member that is necessarily seen frequently but one that is seen frequently as a member of the category. ?People?s perceptions of how frequently exemplars instantiate their category, rather than people?s familiarity with exemplars, appears to be the measure of frequency that is most central to graded structure? (Barsalou 1987). The bike is an appropriate and, for a child, prototypical instance of this schema, as it tends to keep rolling when on a flat surface ? unlike when walking or running. Schema 2: Intrinsic Motion The analogies introduced by Connor and Kamran are rooted in a schema different from Adam?s and more consistent with a phenomenological primitive. First consider the evolution of Connor?s analogies. Connor jumps from analogy to analogy ? first the baseball bat, which he discards when he analyzes it further, then the bus with a leaf, which evolves to the bus with a rock when he is pressed by Lauren. These are chosen because he believes that you will need to release the bean-bag after passing the X. This belief is evidence of a schema in which dropped items will be pushed backwards ? and he is able to invoke two analogies as evidence. The prototypicality of these will be discussed in further detail in the next section, but a brief sketch is provided here. When switching to the bus analogy, there is no reason for the bus with a rock to be any more salient and immediate an analogy than the bus with a leaf unless Connor has a schema in mind already: one involving the ?wind? pushing the object back, in which case a leaf is much more prototypical in this scenario than a rock, even though the rock has features (heaviness and irregular shape) that would make it much closer to the beanbag. Lauren 135 picks up on Connor?s selection of analogy as representing a category to which the keys would not belong, as they are heavy, and a person would not belong, as people are slower than buses. She suggests that ?the leaves are really, really light, so the reason they are going backward is because, um, well it?s going so fast ? a bus is like going so fast that it?s probably making the air go that way.? Only then does Connor move his analogy ?closer? to the beanbag by posing the question ?what if you did it with a rock?? It is Kamran who identifies the two categories that are invoked by these students? schemas. I would like to suggest that the students are employing the p-prim of ?intrinsic or spontaneous motion? (diSessa 1993), which has a schematization of ?especially heavy or large things resist motion.? Such a p-prim creates a dichotomy of objects that do and objects that don?t resist motion (Adam?s schema of ?an object in motion will stay in motion? has no such dichotomy in Newtonian physics, but in ?real world? physics there seem to be objects that obey this law and ones that don?t). Kamran, a particularly vocal student who seems to voice his thought process, grapples with the categories that have been invoked by Connor?s analogies: he wants to say that the rock and the leaf belong to different classes of objects, and yet he knows that they are both solids. An illuminating comment is made when Kamran states that ?a rock is different? but it?s not that a leaf isn?t solid, or a feather isn?t solid.? In this passage, we see Kamran negotiating the two categories that have been instantiated by Connor?s schema, trying to match these categories with known categories (solids) but coming up empty: ?A rock is different, a rock has ? it?s also like, it?s solid, but it?s not that a leaf isn?t solid, or a feather isn?t solid.? He struggles to identify the ways in which these items could belong in different categories by identifying multiple members of those categories: a feather and 136 a paper box as belonging to the category for which leaves are a prototype. But again he is stumped by the tree ? ?heavier than all the leaves it has? ? as an object in the category for which the rock is prototypical, yet constructed of items for which the feather is prototpyical 2 . Kamran, because of his transparent thought process, demonstrates that these analogies are clearly defining certain categories and the task the students have is to determine to which category the keys belong. The choice of base in these analogies is discussed in the following section, in which I address prototypes of ?composite? categories, such as things that you drop and items from which you drop them (running and bats, buses and rocks, etc). Styrofoam and ice-skating The following set of analogies is taken from an undergraduate physics course. This course is a laboratory based conceptual physics course at the University of Maryland in which the students have no textbook and work in small groups and as a class to understand physical phenomena. In the following transcript, the students have worked in small groups, discussing the differences between what it?s like for a charge in metal versus Styrofoam, and are now reporting and discussing their conclusions. The following analogies were drawn below were presented for their evidence of multiple analogies. I return to these here and identify the role that schemas play, and the reschematization that the analogies perform (transcript 1, lines 1 ? 107). These analogies are assertions of categorization, and hence derivative of a schema, the base a prototype of the categories 2 An alternative interpretation of this statement is that the tree shows how weight is the significant factor ? ?It has leaves that want to make it fly, but it doesn?t because the tree is so heavy.? 137 defined within and organized by that schema, and multiple analogies as a way of negotiating that category. Schemas For a person, motion through something dense ? a dense crowd, say, or a densely furnished room ? is usually difficult. Motion is generally easiest in a medium that is not very dense. No one addresses this explicitly with analogy, again indicative of what diSessa has called the ?principle of obviousness.? However, students have noticed that charges appear to move easily in metals and are somehow ?stuck? in the less dense Styrofoam and recognize the paradox. This paradox demands that one categorize the motion of charges in a way that violates some expectations regarding motion. As such, it requires explanation and students are able to identify a schema in which this is not a paradox. By setting up an analogy the students are able to recategorize the metal and Styrofoam in a way consistent with schemas already at their disposal. Initially Christie suggests that the metal must be less dense ? but, I contend, what Christie means by suggesting that metal is less dense than Styrofoam is that in a metal the motion of charges is easy, and so the metal belongs to a class of objects that allow for motion ? a class often typified by low-density places. Lea?s analogy identifies a case in which density enables rather than inhibits movement: ice-skating. Multiple Analogies In the above section, the phenomenological primitive of ?intrinsic or spontaneous motion? (diSessa 1993) has a schematization of ?especially heavy or large things resist motion? that establishes two categories (things that resist motion and things that do not). 138 Similarly, the schema of density enabling motion creates two categories: items that are dense enough to enable motion and items that are too not-dense and prohibit motion. The instructor, identifying this second category in this schema, finds a prototype: the sponge. Though not dense, it will not allow water to pass through easily. And Lea mentions water on a countertop and then the instructor makes an analogy to stepping-stones ? analogies which, when viewed as an assertion of categorization, identify more members of the category typified by ice-skating. Prototypicality Claims of prototypicality are difficult to make: without doing an explicit study of the graded structure of the ad hoc category ?media whose density enables motion,? determining the prototypicality of a statement can only be inferred. However, some principles of prototypes can aid us in determining or arguing for the prototypicality of a particular base of an analogy. Rosch (1976) reports that prototypes appear to be just those members of a category which most reflect the redundancy structure of the category as a whole. Categories form to maximize the information rich clusters of attributes in the environment and, thus, the cue validity of the attributes of categories. Prototypes of categories appear to form in such a manner as to maximize the clusters and cue validity within categories. For this reason, the prototypical bird would be one that is small, has feathers and wings and can fly. But defining prototypicality in a category that is not taxonomic, but instead one that is either goal based (as ?foods to eat on a diet? for example) or otherwise ad hoc, such as ?a medium for which density enables mobility,? is difficult. Though ad hoc categories have a graded structure, ?there appears to be a large class of determinants that is impossible to specify completely and that depends to some extent on the category and 139 on the context in which it is perceived? (Barsalou, 1987 p. 104). Factors determining the graded structure include: ? Central tendency ? for example, the features of birds mentioned above. ? Similarity to ideals associated with that category ?where ideals are properties that exemplars should have if they are to best serve goals associated with their category.? (Barsalou, 1987 p 105) For example, low-calorie foods for the category of things to eat when on a diet. ? How frequently it is perceived as instantiating its category. ?People?s perceptions of how frequently exemplars instantiate their category, rather than people?s familiarity with exemplars, appears to be the measure of frequency that is most central to graded structure.? (Barsalou 1987) And yet these arguments still beg the question: why is a leaf falling from a bus (Analogy II) prototypical? Surely this scenario is infrequently, if ever, perceived. And what is meant by ?central tendency? is difficult to ascertain in a relatively composite category for, as noted by Lakoff (1987 b ?Cognitive Models and Prototype Theory?), a good example of a striped apple is neither a good example of striped things nor a good example of apples, and a small galaxy is not the intersection of prototypically small things and galaxies. Similarly, ?things that fall behind you when dropped? is not the intersection of things that you drop and things that fall at an angle, while ice is not a good example of dense media and skating is not prototypical of motion. To explain these as prototypes for the categories they instantiate, the claim of ?similarity to ideals associated with that category? is more informative. However, defining those ideals requires an appeal to idealized cognitive models, schemas and p- 140 prims. In particular, I argue that the schemas that are being employed in the bus-leaf analogy and the ice-skating analogy are built from multiple p-prims. These p-prims are put together in a larger composite schema that is then concretized by the base of the analogy. The prototype structure ? the fact that something is identified most quickly and is a better exemplar of the category ? need not imply that the prototype is a permanent fixture stored in memory as a representation of a schema, but rather that, under these circumstances and in this set of activated schemas, this particular representation of the schema is accessed most easily. Miranda?s analogy hinged on a single p-prim (namely carrying), but her selection for the base of her analogy arose from this schema (carrying) together with the upside- down property of the cup and even, perhaps, the idea that ?something weird? would happen. The analogies presented in the past two transcripts are also based on phenomena more complex than a single p-prim. Consider the schema that Connor may have: I posit that Connor has two stories or schemas that this beanbag-running-drop invokes: one is simply the schema of running and dropping something, for which baseball and the bat is quite prototypical and is tied to a second schema of what happens after that drop occurs. This second schema is something like ?things in motion are pushed backwards by the wind.? This schema, contrary to Adam?s schema of ?things in motion stay in motion until stopped,? may entail the p-prims (all quotations from diSessa 1993) ?intrinsic or spontaneous resistance? (with a schematization of ?especially heavy or large things resist motion?), and ?force as mover? (here the ?wind? force moving the leaf). Such a schema would explain why Connor rejects his initial analogy (it is derivative of a different schema than addresses the question at hand, namely things that you drop as you run) and 141 explains his choice of objects for the second analogy he chooses. The leaf is prototypical ? readily activated within this schema ? in that it is consistently a member of object that are affected by wind, and the bus is prototypical in that it consistently creates this ?wind? force (or, as Lauren says, ?well it?s going so fast ? a bus is like going so fast that it?s probably making the air go that way?) and is an object with which students are quite familiar. The analogies surrounding the motion of a charged particle in metal (an aluminum pie plate) hinge on the idea that density is in some way enabling motion. One implication from the initial analogies (ice skating, a countertop and a sponge) suggest to one student that the charges are moving across the top of the metal (transcript 1, lines 83 ? 86), which she finds problematic because charges should be throughout the metal (?it?s made up of it?): Anna:So you?re saying the charge is like on top of the metal? Like on the outside? Lea: Yes. Anna:It?s like made up of it ? like, they?re electrons. Lydia agrees with the student above and suggests that the electrons, instead of ?skating? across the solid metal, are hopping from one molecule to the next. Paul then concretizes the schema, selecting an analogy to stepping-stones (transcript 1, lines 113 ? 121): Lydia: I was going to say I think the pie plate is more dense but I do think that it?s inside not outside because if there?s more space to travel then the molecules can?t get from one space to another easily but it?s all [inaudible]. Instructor: Oh so it?s like stepping stones [Lydia: Kind of.] like in the Styrofoam it?s really far to the next stepping stone so it?s like can?t get there I?m stuck here. [Lydia: Right] but in the metal the stones are really close together so I can kind of walk across. [Lydia: Yeah.] 142 The base of the analogy comes from the schema, and ? just as happens in the beanbag analogies ? as that schema changes, so do the analogies. Analogies regarding a quantum mechanics problem The following transcript, presented in the previous chapter, follows two undergraduate physics majors working on a homework assignment on angular momentum in quantum mechanics. The students have had instruction on how to arrive at the quantum numbers S and L but are asked to find the square of the total angular momentum, (J) 2 , which is (S + L) 2 , or (S) 2 +2(S?L)+(L) 2 . The students know how to find (S) 2 and (L) 2 but not 2(S?L). They have a solution set from another student that provides the answer but not the steps to arrive at that answer. There are two analogies presented in the transcript, both an expression of the kind of problem they are solving: how to approach the problem and how to understand the quantities in the problem. The first (transcript 5, Lines 10 ? 27): Anselm: ?Cause you?re assuming that if you have the example, suppose there?s a charge here, what?s the electric field due to it? You can figure out, suppose you have Bugs Bunny, and he?s charged, what?s the electric field around his ears? All right. Because you have a simple example when they?re both the same, you?re not going to be able to figure out exactly what you?re supposed to do when the rules weren?t the same. Cause now it?s fixed. And then, (transcript 5, lines 64 ? 80): Ben: But you?re mixing apples and oranges. It?s dumb! Anselm: Yeah that?s so messed up, yeah that?s not the answer. If I just ignore the fact that I?m in the three-halves one-half and I?m in the one-half one-half and I just add them all together, Ben: I once had a professor tell me that um, well if you got the right answer, you certainly know how to do the problem. I had to convince him no sir, you can jiggle these numbers any way you want. And come up with the right answer if you know the right 143 answer in advance. Of course we?re not sure that this is the right answer. Reschematization of the base What kind of analogies should one expect in discussions of quantum mechanics? What schemas are available to understand this branch of physics that has no obvious analogs? In this discussion between two students, their analogies are with respect to mathematics and problem-solving strategies, not concerning the nature of quantum mechanics. While this transcript is not long enough to draw any meaningful information regarding analogies in quantum mechanics, it is interesting to note that the schemas introduced here are not regarding wavefunctions or expectation values, but instead related to problem solving and epistemology. The first analogy is a response by Anselm to Ben?s claim ?We should be able to figure this out from today?s lecture.? Ben believes they should be able to solve the problem with information from the day?s lecture on simple quantum numbers. Anselm offers an analogous case and then provides the abstract schema from which that case was derived: ?Suppose you have Bugs Bunny, and he?s charged, what?s the electric field around his ears? All right. Because you have a simple example when they?re both the same, you?re not going to be able to figure out exactly what you?re supposed to do when the rules weren?t the same.? It is clear that Anselm?s analogy is a reschematization ? this problem is not one that can be solved from simple principles but requires more sophisticated tools. The second analogy is, again, a reschematization. The students know what the correct numerical answer is and are trying different combinations of numbers in the 144 problem to arrive at that answer. When dealing with numbers in many (if not most) mathematics courses, there are rarely rules about which numbers can be combined and in what order. In situations when numbers have physical meaning ? as in this physics problem ? there are rules about what kinds of numbers may be added and in what way. These rules have been temporarily ignored to find a pattern by which the students may arrive at the correct answer, but when the answer is arrived at, Ben notes the need to reschematize the problem from one of combining numbers without physical meaning to recognizing the meaning (or lack thereof) behind the math, claiming: ?But you?re mixing apples and oranges. It?s dumb!? He then tells a story (in what could be interpreted to be a multiple analogy) that relates this idea again and reiterates the reschematization ? beginning with the professor?s claim that ?if you got the right answer, you certainly know how to do the problem? and then contrasting that with the story: ?you can jiggle these numbers any way you want. And come up with the right answer if you know the right answer in advance.? In telling the story he tells the more abstract schemas that apply. And again, each schema is locally coherent ? it is a routine that makes sense in a limited set of problems. The ontology of authenticity Reschematization of the base This analogy, from a Physics Education Research Group research meeting, was presented previously for the chain of analogies it presents. The meeting is being run by Paul who is trying out a definition of ?authentic? in the context of classroom activities. He has chosen to define authenticity as not only a property of the activity, but also relating to the students? interaction with that activity and the (science) community of 145 practice?s judgment of the activity. (For example, how would the students characterize the reason for what they?re doing? Would scientists agree with that reason?) Not only is this is at odds with common definitions of ?authentic? curricula as a property of the curriculum itself, but it is contrary to a cognitive model of attributes in which a property is a property of something: defined relatively objectively and inherent to that something. Most adjectives or properties belong to this kind of ontology: if I claim that a car is fast, red, and Japanese, for example, there is an objective measure of the truth of that claim that is independent of culture, personality, or me. Anyone else looking at that car will agree that it is fast, red and Japanese. If I have an authentic pearl earring, authentic is used in the same way: an objective measure and a property of the pearl, independent of context. Rachel asserts an analogy to make explicit claims on the ontology of authenticity: ontologically, authenticity is not like fast, red or Japanese. She finds an attribute (fun) that is easily understood as not being inherent in an activity. (Transcript 3, lines 9 ? 29). There is an entire story, or schema or cognitive model, associated with ?fun,? and ?fun? occupies a role in this story. Similarly, authenticity, Paul argues, has a similar story and occupies the same role in that story. This ?role? is a category ? one generated by the schema. However, there is a fundamental difference between the story that you tell for ?fun? and that Paul is trying to tell about ?authenticity? ? there is a community of practice argument. Leslie (I) introduces this question ? first identifying the schema and then moving towards finding the analogy (transcript 3, lines 38 ? 79). Rachel prefaces her analogy by claiming that the analogy will be one of ontology. The ?work? that this analogy does for the group is to say: what you?re doing with 146 authenticity is not new ? we have a way of thinking about this. You (Paul) are placing ?authenticity? into an existing ontology ? one that is characterized by ?fun.? Leslie?s (my) concern was that the ontology was not entirely consistent with Paul?s definition. Whereas the ?fun? of an activity can be determined solely by the person doing the activity, Paul relates authenticity to a community of practice ? so that a scientific community must agree with the student?s judgment of an activity. Attempts to ?patch? the analogy by considering ?good, clean fun? instead of just ?fun? are an attempt to change the ontology of that base. ?Worship? was chosen by Leslie because of its relationship to both an individual and a community. Conclusion How is a concept represented in memory? Is it represented by the kind of knowledge it is? The way that you find its solution? By the ontology of the items in the concept? Is there a stable representation of ?apples? as ?the thing that can?t be compared to oranges?? A representation of Bugs Bunny as ?a strange shape for which the electric field would be difficult to construct?? Is money represented as currency or wealth? If we ascribe to concepts a particular representation in memory, then Bugs Bunny would have to have such an attribute (or, at the very least, would have to be connected to these ideas) and Marc and Vic would have to have different concepts of the ontology of money. Theories of analogy that attribute stable representations to concepts must account for the overwhelming number of features that are part of the representation of a concept. As mentioned previously, to account for the nature of categories, in particular their graded structure, Lakoff (1987) has proposed that categories are defined within particular idealized cognitive models (ICMs) of how the world works. It is only within a 147 particular ICM (or schema) that a category is meaningful, and these categories become les meaningful and exhibit a graded structure to the degree that the schema in which they are defined does not apply. Categories, then, arise from schemas which are activated or not, applicable or not, depending on context. Because of the variety of schemas and the variety of ways they may be combined, categories can have a flexible structure, and members of categories can shift their membership. Categories need not have a fixed representation, but arise from the particular schemas and resources that are activated by the context. As an alternative to structure-mapping and other theories of analogies that require unitary representations of concepts, I posit that analogies are assertions of categorization. Instead of ?preexisting metaphorical mappings? (Gibbs, 1992) analogies instantiate preexisting schemas and their associated categories. Categorization does not require that there be stored representations of concepts or categories, but that ?concepts originate in a highly flexible process that retrieves generic and episodic information from long-term memory to construct temporary constructs in working memory? (Barsalou 1987). 148 Chapter 6: Analogies in the History of Science Introduction The past two chapters are the bulk of the dissertation ? starting with the properties of generated analogies in science (that is, the phenomenology) and then addressing an ontology of mind to account for these properties. In this chapter, I introduce the ways in which analogies have historically been used in science and explore the consistency between analogies in science and the model of analogies introduced in the previous chapters. These analogies are detailed in works of comparative literature, popularized science, cognitive science and the history of science. I begin with analogies from physics and how the role of physical analogy ? namely Maxwell?s analogy between magnetism and gears ? is understood in the philosophy of science. Then I turn to biology and the idea that the theories introduced by science are often brought about by the recognition or activation of a schema. That is, identifying and projecting schemas ? one important part of analogy ? is how science happens. However, schema projection is not the whole story ? often the projection of a schema is implicit, and it is the deliberate use of a contradictory schema that I define to be analogy. I then consider the deliberate use of analogy and the ways in which this has come to be understood by historians of science and cognitive scientists. In Metaphors We Live By (1980) Lakoff and Johnson argue that metaphors structure our thoughts and influence our conceptions of the world, and that the role of metaphor in scientific thinking provides one of the best illustrations of this principle: 149 ?Formal scientific theories are attempts to consistently extend a set of ontological and structural metaphors.? This claim that scientific theories are extensions of the metaphors that we employ in other areas is nothing new. In the 1850?s, with the development of the telegraph and its influence on theories of the nervous system, many scientists recognized, and at least one scientist argued against, the epistemological value of analogy in science. As noted by Laura Otis (2002), Claude Bernard (1858) criticized the analogy between nerves and the telegraph, claiming, ?people?s ?knowledge? of the nervous system had consisted largely of a series of comparisons, ?the expression of a way of seeing meant to explain the facts.? Priding himself on his empiricism, Bernard mistrusted analogy as a means of constructing knowledge.? This concern ? that analogies (a ?way of seeing?) masquerade as understanding (?explain the facts?) ? was echoed in a cognitive science course at the University of Maryland. The professor noted that cognitive scientists have employed the idea of ?outshining? to explain phenomena in which stimuli we usually attend to are ignored in the presence of other stimuli, analogous to the way in which the sun ?outshines? the stars during the day. Star?s light is not weakened by the sun?s light but ?outshone? so that they are not seen. Outshining in the solar sense, he argued, has an understood mechanism, while outshining in the cognitive science sense cannot realistically have the same mechanism, but no mechanism is proposed. In this case, the analogy masks the lack of understanding. What is missing from this analogy? What role does ?outshining? serve? Why mention it at all if it does not contribute to the understanding? What, exactly, is the epistemological value of analogy? First, I have argued, the importance of an analogy is its assertion of an unexpected categorization, meaning that you are identifying an alternative cognitive model for this 150 scenario. In the case of ?outshining,? the analogy functions, as all analogies do, to reschematize the phenomenon. For outshining, the reschematization is changing the cognitive model from one in which stimuli are responded to on the basis of their absolute value, and instead responded to only by their relative value. Such analogies in science, because they are an assertion of categorization, and therefore shift the cognitive model applied in understanding the target, is what Koestler has identified as the ?essence of creativity:? being able to view a situation or an object from two different frames of reference, or two ?unrelated matrices of thought? (Koestler, 1964). Or, as Chi (1997) states, ?the essence of creativity is? re-representing an entity or a situation from one ?ontological? tree of concepts and categories to another ontological tree of concepts and categories.? (Although I differ from Chi in the robustness and structure of those ?trees? ? these activated schemas may be put together in a wholly new way to understand the new phenomenon.) Second, re-categorizing the target of the analogy is extremely powerful: not just because of the inferences one may draw, but because it affords one a new language. Once the target is understood through the lens of a different (and possibly more appropriate) cognitive model, the target may now be referred to using the language and categories defined within the new cognitive model. It is within this new framework that a structure-mapping process may take place to construct a mechanism ? a crucial and necessary step for employing the analogy ? but the primary role of analogy is the entrance into that cognitive model ? to ?tie it down? in a concrete way ? and access to a new language with new categories. This new framework is similar to what Otis (2002) 151 refers to as a new image (her use of the term ?image? is not in the sense of image-schema or image-representation): Metaphors provoke and give birth to new images. By establishing and reinforcing connections, they encourage us to see in new ways. While Bernard is correct that assertions of likeness alter the way we see, Lakoff and Johnson are equally correct in claiming that ?much of cultural change arises from the introduction of new metaphorical concepts and the loss of old ones.? Alterations in the way we see can be extremely productive. Because of this process of theory building via analogy, our scientific theories are often an extension of the stories that our lives tell: through our political systems, technology, and experiences. This chapter is not intended to be an in-depth analysis of the evolution of theories in the history of science. Instead I draw from the work of others regarding the history of science and explore the consistency between their ideas and my definition of analogy. I will explain how several theories that are clearly based in analogy and detailed in comparative literature (Otis, discussing Ram?n y Cajal), popularized science (Burr, writing about Turin), cognitive science (Gentner on Kepler), and the history of science (Nersessian on Maxwell) are consistent with a category framework of analogy. This is not to say that all scientific theories evolve via analogy to known systems; rather, I claim that the process of analogy is prevalent in the scientific community and the manner in which analogies are used is consistent with a categorization framework. History and Philosophy of Science I begin with examples in the history and philosophy of science from physics. As noted in the first chapter, it is not hard to find instances of analogy in the creation of theories in physics. Einstein, who had a background in physics, was working as a patent 152 clerk in Switzerland during an era of train travel (Galison, 2003). A great deal of patents at that time involved synchronizing clocks from one station to the next ? and Einstein?s special theory of relativity was often described (by Einstein and others) as a question of synchronizing clocks on a train. Kosterlitz and Thouless (1973) drew an analogy between order parameters and their associated phases on the one hand and topology on the other. Nancy Nersessian, a philosopher of science, has studied what is referred to as ?the method of physical analogy.? She studies model-based reasoning, such as the type employed by Maxwell in determining the electromagnetic field equations. Maxwell constructed a model of electromagnetism in materials that consisted of vorticies that created a series of interlocking gears ? ?idle gears.? Nersessian has developed a hypothesis regarding the manner in which mental- modeling works and how it is employed by scientists. Her mental-modeling hypothesis is that In certain problem-solving tasks humans reason by constructing an internal iconic model of the situations, events, and processes that in dynamic cases can be manipulated through simulation. In constructing a model, information in various formats, including linguistic, formulaic, and imagistic, where the latter is taken here to include various perceptual modalities, can be used. A question that is often asked of model-based reasoning is that, given that the model is an existing and understood model, how can model-based reasoning ?be generative of conceptual change in science?? To this Nersessian responds that it ?requires a fundamental revision of the understanding of concepts, conceptual structures, conceptual change, and reasoning.? To address this concern, Nersessian argues, we must revise the notion of a concept: 153 A basic ingredient of the revision is to view the representation of a concept as providing sets of constraints for generating members of classes of models. Concept formation and change is a process of generating new, and modifying existing, constraints. This is accomplished through iteratively constructing models embodying specific constraints until a model of the same type with respect to the salient constraints of the phenomena under investigation, the ?target? phenomena, is achieved. (Nersessian, 2002, p 139) I would like to stress from this the claim that the representation of a concept is a set of constraints for generating new members of classes of models. The set of constraints is identified by finding analogous cases (in the case of Nersessian?s studies, these analogous cases are models) and a case is deemed analogous by being one of the ?same type with respect to the salient constraints of the phenomena.? Mental-models, then, which are prevalent in the development of scientific theories, operate by being members of a class ? a prototype of a category, I argue ? that are useful for their ability to determine the set of constraints necessary for the representation of a concept. Though the final negotiation of the set of constraints may be a structure-mapping process between the particular base of the analogy (or model in the method of physical analogy), the primary role of analogy ? the assertion made when the analogy first is introduced ? is one of categorization 1 . Again, the categorization is indicative of a particular cognitive model and that model creates a language for discussing the concept. This differs from structure-mapping theories of analogy in that the significance is not tied to the base in particular except for its role in being a prototype for a category invoked by a common schema. Nersessian (2002, p. 138) writes, 1 Another possible interpretation, which I will not go into in detail here, is that this category is a wholly new category that represents a ?blended space? as detailed by Fauconnier and Turner (1994). This idea will be explored in the conclusion as a possible direction for further research. 154 In model-based reasoning processes, a central objective is to create a model that is of the same kind with respect to salient dimensions of the target phenomena one is trying to represent. Thus, although an instance of a model is specific, inferences made with it in a reasoning process are generic. In viewing a model generically, one takes it as representing features, such as structure and behaviors, common to members of a class of phenomena. The relation between the generic model and the specific instantiation is similar to the type-token distinction used in logic. Generality in representation is achieved by interpreting the components of the representation as referring to object, property, relation, or behavior types rather than tokens of these. One cannot draw or imagine a ?triangle in general? but only some specific instance of a triangle? In considering the behavior of a physical system such as a spring, again one often draws or imagines a specific representation? That is, the reasoning context demands that the interpretation of the specific spring be generic.? The point that I take from this for my thesis is that the base of an analogy is more abstract than a particular analogy appears. Maxwell?s analogies of idle gears was no more tied to that particular representation of idle gears than claiming two ideas are ?apples and oranges? is tied to any particular instance of comparing apples and oranges. It is simply a prototypical instance of a class of phenomena that share a place within a certain cognitive model. Similarly, Miranda?s analogy to the toy cat was only one salient example of the story (or cognitive model or phenomenological primitive) of carrying. The base of the analogy refers to a category ? ?one takes it as representing features, such as structure and behaviors, common to members of a class of phenomena? (emphasis added). And the base in particular is chosen only because we cannot imagine categories in general or reason about them generically but must choose a single representation to reason with. This representation is what researchers in categorization have termed the category prototype. 155 Comparative Literature I now turn from physics to biology: first findings from comparative literature and then a reiteration of these findings from studies on scent. The following ideas from comparative literature are by a professor who has a background in biology. The idea that her findings underscore is that our science evolves from the cognitive models that we have in mind, as provided by our culture and technology. Membranes Otis (1999), a professor of comparative literature, was pursuing the concept of identity as scientist-authors in the 1800?s defined it. In particular, she explored how ?the changing understandings of personal and national identity encouraged people of the 1830?s to see living things as associations of independent units? (Otis, 2001). Both the political climate of colonialism and the scientific studies of cells created the ideas of entities with porous but definite membrane borders. In her work Membranes (Otis, 1999), she writes: In their respective languages, all of these physician-authors confront their cultures? demands for borders, and they express and challenge them through common metaphors and maneuvers. This coincidence suggests that imperialistic culture, which offers the same metaphors to scientists and novelists, shapes both biology and literature by shaping the language through which they express themselves? the relationship between literature and science is one of mutual feedback and suggestibilty, each contributing to and drawing up on the ?cultural medium? out of which it grows. Culture, however, does not ?determine? science or literature any more than science and literature determine culture: personal vision persists, despite all indoctrination and all scientific training. (p. 3) One particularly illuminating story that Otis tells is that of Ram?n y Cajal, the Nobel Prize winning biologist who determined that the nervous system is made of discrete cells and is not a continuous net-like structure, as it appears. She questions why this had not 156 been determined before ? Golgi had invented the necessary techniques years before Ram?n y Cajal employed it in studies of nerves ? and she questions ?what was it, I wondered, that drove Ram?n y Cajal to keep looking, determined to resolve boundaries between cells when there appeared to be no boundaries at all?? The answer, she determines, is that the cultural medium of the time was creating a particular vision: Many factors besides the essential technical ones affect what one sees under a microscope, or at least the way one describes it. It has been proposed, for instance, that late 18th-century German philosophy, with its stress on individual perception, inspired people in many fields to conceive of life in terms of independent living units (Rothfield, 97). How might politics and culture shaped cell theory?? Cell theory relies on the ability to perceive borders? Germ theory? encourages one to think in terms of ?inside? and ?outside.? If one believes that invisible germs, spread by human contact, can make one sick, one becomes more and more anxious about penetration and about any connection with other people ? the same anxieties inspired by imperialism? (Otis 1999 p 5). That is to say, the cultural medium in which science exists strongly influences the way in which data is seen: the existing stories the culture has constructed provide expectations for the data. Her study on the connection between national agenda, scientific theory and literature, compels Otis to claim that ?the division between the humanities and the natural sciences [is] another boundary arbitrarily drawn. Scholars on both sides of the line want to answer the same questions, and we express ourselves through metaphors provided by a common culture.? It is no secret, particularly within qualitative studies, that our culture biases our interpretation of data. What Otis demands that we recognize is that our culture influences our hard sciences as well as our art, and it does it in the same way. This echoes a comment by Robert Irwin, an abstract artist who was paired with a physicist in ?cultural exchange? experiment. Initially both artist and scientist were pessimistic on the merits of this pairing, but quickly found that they were both addressing common 157 questions with their work and found collaboration easy. Irwin, in his biography, comments: I really feel that there is a kind of dialog of immanence. That certain questions become demanding and potentially answerable at a certain point in time, and that everyone involved on a particular level of asking questions, whether he is a physicist or a philosopher or an artist, is essentially involved in the same questions. They are universal in that sense. And although we may use different methods to come at them, even different thought forms in terms of how we deal with them ? and we will eventually use a different methodology in terms of how we innovate them ? still, really those questions are happening at the same moment in time. So that when we find these so-called accidental interrelationships between art and science, I don't think they're accidental at all. -Robert Irwin This ?dialog of immanence? I believe is related to what Otis refers to as the ?cultural medium.? The ?certain questions? that become demanding are those that our paradigms provide us. And those paradigms are not so local as Kuhn (1970) suggests in his Structure of Scientific Revolutions ? they can be broad cultural paradigms. They are the cognitive models supplied by our daily experience in our culture. These models (stories or schemas) are responsible for our categories, which in turn allow us to be creative and reconceptualize our science, art, medicine, political systems and economies. If creativity is a shifting of categorization (?re-representing an entity or a situation from one ?ontological? tree of concepts and categories to another ontological tree of concepts and categories? Chi, 1997), and analogies are assertions of that unexpected categorization, then it is changes in our cultural medium 2 that provides us with the new categories, 2 It is not, of course, such a strong dichotomy: culture versus science. Art, technology and science are all contributing to the cultural climate. The point that Otis is making, though, is that these parts of culture are far more intertwined than previously thought. Culture, as defined by the political climate in particular, influences science ? hard science ? far more than one would think and the way it does it is by giving us new schemas and the new language associated with those. 158 derivative of new cognitive models, in the first place that allow us to be creative. These ?accidental interrelationships? (Wechsler/Irwin), are not accidental at all, but are due to the ?metaphors our culture provides us? (Otis, above). And these metaphors are not simply local structures that we map but are creating new ontologies, new categories, derivative of new cognitive models. So far, this points to the following: we see ? in our data and in our art ? what we expect to see and those expectations come from the cognitive models we have developed from our experiences and our culture. We understand and categorize phenomena based on the cognitive models that we have in place. But this is only part of the story. For this still begs the question: is this analogy? Insofar as I have defined it, unless there is an explicit negative assertion, where the mind considers two possible schemas ? each coherent within its own framework, but only one of which is possible ? then this is not analogy. Ram?n y Cajal?s insistence on looking for membranes may be such an instance, but it is not clear from the story provided. It is doubtful that he understood his research in the larger cultural paradigm and deliberately chose a schema of boundaries over the continuum model. Rather, this insistence on borders and boundaries in what are otherwise continuous, unbounded regions, sets up a particular resource and this resource is continually activated by the culture. It was, perhaps, never a deliberate cognitive ?choice? to activate it. For a case that is more clearly one of analogy, consider the role of networks and the telegraph on understanding the nervous system. 159 Networks Otis? first study, a study on identity, led her to a realization that the concept of membranes pervaded literature and science at a time when the political climate of imperialism demanded the idea of borders. In a second study, Otis (2001) explores the idea of communication and traces the idea of networks, again looking at the nervous system and its theoretical development as consistent with the telegraph. Just as McLuhan professed, ?the medium is the message,? so Otis (2001) finds that the message cannot be ?abstracted from the medium that transmits it.? In particular, the advent of electronic communication has forced a reconceptualization of our selves: Since the late 1840?s, electronic communications networks have changed the way we see our bodies, our neighbors, and the world. For a century and a half, these networks have suggested webs, leading their users to think as though they were part of a net. Between 1845 and 1895, the development of the telegraph transformed people?s understanding of communication and, with it, their notion of their relation to others. As the telegraph affected language, Carey argues, it ?changed the forms of social relations mediated by language? (Carey, James, 1989 p 210). The telegraph became ?a thing to think with,? shaping the thoughts that it wired. (Carey p 204) In the seventeenth century it was thought that muscular motion, determined in the brain, was mediated by pressures in a nervous fluid. As Otis (2001, p. 14) notes: ?observing the brain?s ventricles filled with cerebrospinal fluid, the earliest anatomists envisioned the nerves as a kind of circulatory system, drawing inferences about their structure and function by comparing them to a system whose structure and function were more obvious.? Though criticisms of this mechanism were made and scientists (namely Galvani) argued for replacing the hydraulic model of the nervous system with an electronic model, this alternative was not adopted until after the advent of the telegraph. As Lenoir (1993) argues, scientists? familiarity with electrical circuits affects ?not just the 160 way they performed their experiments but the way they conceived of the nervous system itself.? That is, the technology allowed for a change in theory ? and not because of the ability to make new measurements (telegraphs as a technology are not a tool for discovery in that sense), nor because of the change in theory regarding telegraphs (electricity was understood well enough to created the telegraph but was not applied to nerves until after the telegraph was invented), but because of a cognitive model that it afforded, allowing scientists to see and categorize phenomena that they had no way of understanding otherwise. In this century, the nervous system is referred to ?in the language of the cybernetic web? (Otis, 2001). Indeed, even the idea of where thought occurs has moved from the brain to this interconnected web in the paradigm of distributed cognition (Brown, Collins, and Duguid, 1989) ? an idea that one could argue finds its origins in the transmission and growth of knowledge enabled by the internet. This relationship between technology and theory ? in which technology is not only created by changing theories, but often vice versa ? can offer an explanation for Robert Irwin?s observation that artists and scientists seem to address questions that become ?potentially answerable at a certain point in time.? These questions arise because, as Otis claims, ?the technological metaphors affected? decisions about which phenomena to study and what experiments to perform.? (p 3) Not only because or technology affects what we can study, but what we choose to study and how we represent and understand our findings. Some ideas seep into the consciousness of our culture ? through our language and technology ? so that we cannot help but use these ideas as a lens on other phenomena. Some ideas require an explicit cognitive work ? it is a lens you must ?put on? to see 161 phenomena in a new way. With Ram?n y Cajal?s work on cell membranes, the lens was perhaps unconscious. But with the electrical properties of the nervous system the analogies were explicit (Dubois-Reymond, 1868 p 97): just as little telegraph wires, do the nerves betray by any external symptom that any or what news is speeding along them; and, like those wires, in order to be fit for service, they must be entire. But, unlike those wires, they do not, once cut, recover their conducting power when their ends are caused to meet again. Again, this explicit use of analogy reiterates the manner in which certain implicit metaphors and categorization differ from deliberate analogy. Though many researchers place analogy on a continuum that includes rather mundane instances of similarity and categorization (Gentner and Markman,1997; Hofstadter, 2001), I claim (or more accurately define) that analogy differs from categorization and routine similarity in that analogy requires a reschematization of the target while categorization does not. In the following quote, Otis (2001) notes the problematic distinction between category and analogy: In his Foreward to Kittler?s Discourse Networks, David E. Wellbery declares that ?in its nervous system, the body itself is a medial apparatus (xiv).? He means, of course, that the nervous system is like an electronic medium ? or does he? If they perform the same functions, are nerves like cables or are they identical, members of the same functional category? Metaphors elide likeness, masking a key epistemological link. But what is the epistemological value of metaphor? What does one gain by saying that one thing is like another?? It could be objected that nerves are alive and thus inherently different from any sort of technological apparatus. Since the early nineteenth century, though, drawing a distinction between organic and technological systems has grown increasingly problematic. In this paragraph, Otis notes that the claim of analogical likeness is not so far from the claim of category inclusion. The reason one may wish to say that nerves are ?like? an electronic medium is because of nerves have this quality of being alive ? and so couching this claim in analogy form (?nerves are like cables?) recognizes that there is a 162 violation of expected categorization: living things are not machines. But increasingly this distinction between organic and technological is problematic ? as we begin to understand the human body in terms of machines, this idea may shift from an assertion of analogy (shifting the schematization of the concept) to more routine categorization (in which the ?machine? category no longer differentiates living things from non-living things), in which someone may claim that the body is a medial apparatus ? or even simply use the language of telegraphs to speak of the nervous system ? without there being the tone of analogy present. Below I present a more modern example of technology (the scanning electron microscope) influencing science by providing a schema by which we understand scent, and the way in which the previous understanding of scent had been a rather implicit application of a schema that, in terms of predictions and an understanding of olfaction, was not generative. I then return to theories in physics with an analysis of a historical analogy relating the sun?s relationship to the motion of the planets to the sun?s light. Luca Turin: Analogies involving scent The mystery of our sense of smell stems from the puzzling ability to smell everything instantaneously. In order to smell something, we take particles of it into our nose and these are detected by the olfactory system. However, as noted by Burr (2002), our other systems that detect particles that have come into our body, the digestive system and the immune system, have evolved so that they can either work instantaneously on a limited number of molecules (the digestive system) or can handle a myriad of molecules but take a significant amount of time (the immune system). This stems from the role of enzymes ? the body either has enzymes on hand, perfectly manufactured to bond to the 163 molecule or it must create the enzymes. The digestive system has evolved to have enzymes ready to digest a limited number of molecules and does so immediately, while the immune system has to make them ? a powerful ability that enables us to fight off diseases that we have never in our evolutionary history seen before, but an ability that takes time, hence the difference in response times. The paradox of smell is that the olfactory system can smell a manmade molecule that has never been smelled before and can do so instantaneously. Perhaps unwittingly, prior to Turin?s work on smell, scientists were assuming that smell worked according to the same principles as the digestive and immune systems ? it is only because of this parallel that one should be surprised that the olfactory system can handle novel molecules instantaneously (had they assumed smell worked according to principles similar to sight, where we can see shapes we have never seen before, then this property of smell would not be surprising). Turin?s idea was that smell was not appropriately schematized ? in a sense, the scientists were asking if the Pope is a bachelor. The questions they asked about the sense of smell were difficult to answer because they were not appropriate. Questions asked of enzymes, of shape and timing were not the right questions ? they were questions provided from the schemas associated with the immune system and digestive system, a schema that does not fit the olfactory system ? but with no alternative schema, these were the only questions available to ask. Just as the invention of the telegraph inspired theory of the nervous system, recent developments in microscopy in physics provided an analogy for Turin, a way of reschematizing smell. Turin proposed that smell works according to the same principles as a tunneling microscope: the molecule providing an electrical connection and the strength of that connection related information regarding the 164 structure of the molecule. In this schema, the shape of the molecule is not important, enzymes do not factor into the process of smelling, and a question of how we can smell novel molecules instantaneously is not an issue. As with Otis?s findings in membranes and networks, it was changes in technology that enabled changes in theory: not because the technology was a necessary element in discovery but because the technology created a new schema and allowed the reschematization of smell. Cognitive Science Gentner?s (2002) structure mapping theory has been to understand developments in the history of science. In particular, she has looked at the analogies of Johannes Kepler. Kepler, born in the 1500?s, inherited an astronomy of spheres in which planets circumnavigated the sun by the will of souls (later translated to angels or virtues or spirits). However, there were regularities and features in the data of the motions of the planets that required explanation. In seeking to understand why the planets that were further from the sun moved more slowly, he argued (Kepler, 1596, p199): ?one of two conclusions must be reached: either the moving souls are weaker the further they are from the Sun; or, there is a single moving soul in the center of all the spheres, this is, in the Sun, and it impels each body more strongly in proportion to how near it is. That is, the sun is responsible for the motion of the planets and the closer you are to the sun the more it can make you move ? the sun is transmitting a motive power through space to the planets and this power is closer when one is closer to the sun. To make sense of this argument, he appealed to analogy: I shall propose to the reader the clearly authentic example of light, since it also makes its nest in the sun?Who, I ask, will say that light is something material? Nevertheless, it carries out its operations with respect to place, suffers alteration, is reflected and refracted, and assumes quantities so as to be dense or rare, and to 165 be capable of being taken as a surface wherever it falls upon something illuminable. Now just as it is said in optics, that light does not exist in the intermediate space between the source and the illuminable, this is equally true of the motive power (Kepler, 1609/1992, p 383) To understand the role that analogy plays for Kepler and ?knowledge change? (p 28), Gentner (2002) argues that there are ?at least six ways in which the process of analogical comparison can lead to knowledge change? 1. highlighting and schema abstraction ? extracting common systems from representations? 2. projection of candidate inferences? 3. noticing alignable differences ? becoming aware of contrasts on dimensions that are present in both analogs? 4. re-representation ? altering one or both representations so as to improve the match? 5. incremental analogizing?, and last, the rarest of these, 6. re-structuring ? altering the domain structure of one domain in terms of the other? Gentner then discusses how Kepler used analogy in these ways to effect knowledge change. However, at the end of the article she notes: ?I have focused here on the use of analogies in online thought ? that is, the processes of analogical reasoning once one has both analogs in mind. But it is obviously crucial to ask how potential analogs come to mind.? As noted in chapter 5, and echoed by the findings above by Otis, I argue that the analog (that is, the base of the analogy) is not what is primary: the analogy does not first spring to mind and then induce a ?schema abstraction? (Gentner, 2002). Rather the story (or schema, p-prim, or idealized cognitive model) is primary and this story is what is first accessed. Once accessed or identified, the analog is constructed or identified as a ?prototypical? member of the category that this model defines ? concretizing or unitizing these schemas entailed in the cognitive model. For clarification and further explanation, consider the following visual ?toy? (Fig. 7.1). 166 Recognizing the irony in making an analogy about analogies to clarify my points, I would like to argue two points: first, that it is having a schema for rabbits that allows you to re-represent this drawing and second, that the schema, and not any particular representation of rabbits, is primary. Fig. 7.1 When you shift the representation of this drawing from, say, the duck to the rabbit you can only do so because you know what rabbits look like. You have a ?schema? in mind that allows for long ears and tiny nose, and though the rabbit pictured above may not look exactly like any rabbit you have ever seen, you can quickly recognize elements of the ?rabbit story? that apply here. For Kepler, if the sun did not seem to give off any kind of energy, or if the intensity of light did not decrease with distance, I would like to suggest 167 that not only would there have been no analog for Kepler to draw but that even identifying this ?story? in the case of planetary motion would have been exceedingly improbable: we only see the rabbit because we have seen other rabbits ? because our mind knows what rabbit ears look like. Kepler?s mind knew properties of light ? and so was attuned to recognizing when things decay with distance, that travel through space without being seen and have an effect on objects. This echoes the answer Otis gives to her question, ?what was it, I wondered, that drove Ram?n y Cajal to keep looking, determined to resolve boundaries between cells when there appeared to be no boundaries at all?? That is, the culture had created a story of boundaries and membranes, so that this story could be identified in other places. This idea ? that our abstract ideas stem from our experiences in the world, has also been argued by Lakoff and Nunez (2001) in Where Mathematics Comes From, in which they argue that math is not the abstract ideal that we imagine it to be, but arises from metaphors to physical experience. When you think about it, it seems obvious: The only mathematical ideas that human beings can have are ideas that the human brain allows. We know a lot about what human ideas are like from research in Cognitive Science. Most ideas are unconscious, and that is no less true of mathematical ideas. Abstract ideas, for the most part, arise via conceptual metaphor-a mechanism for projecting embodied (that is, sensory-motor) reasoning to abstract reasoning. (Lakoff and Nunez, 2001 p xxi) Mathematics, as with science, does not simply evolve from the data or from the numbers, but from the ?ideas that the human brain allows.? And these ideas that the human brain allows are the ideas that it has acquired from the surrounding culture and from sensory- motor experience ? they provide us with schemas that we may then project onto new experiences. 168 Structure-mapping suggests that, to re-represent the drawing as a rabbit, one must first imagine a rabbit and then align the features of that rabbit with the features in this drawing. The single representation of a rabbit is primary and is used, together with the rabbit in the picture, to access the more abstract schema. It suggests that we might have to consider a limitless possibility of things ? rabbits, cats, dogs, tables ? and one by one consider the ways in which the structures of these various potential analogs align with the target. Instead, I find far more plausible that the rabbit ?schema,? rather than a particular representation of a rabbit, is primary. We access the analog via the schema, rather than the other way around. (Another point to note is that you are not drawing an analogy between the rabbit and the duck but rather re-representing the drawing, understanding this ?stick-out piece? as ears instead of bill.) Conclusion The impetus for my thesis and the bulk of my support comes from analysis of student-generated analogies in science. However, studies in the history and philosophy of science, comparative literature and cognitive science have developed stories of theory development that are consistent with my claims that derive from student reasoning. These claims, consistent with student-generated analogies, are also consistent with analogies from philosophy and biology. In particular, the ways in which ? analogies are derivative of the schemas provided by the surrounding culture, ? these schemas are primary and are used to access or construct analogs ? the likeness expressed by analogy is a class-inclusion statement, ? concepts are defined as constraints for class-inclusion, and 169 ? the specific is used to represent the general are all consistent with generated analogies as assertions of categorization. In the appendix, I turn from expert scientists? analogies to young students? analogies and find patterns that are reminiscent of the findings reported here. I will return to the ideas from this chapter in the following chapter in which I consider the implications for instruction: if this is what science looks like, and if this is how scientists construct theory, there are profound implications on how students should be taught. 170 Chapter 7: Implications for Instruction How we understand the mind matters? it matters for what we value in ourselves and others ? for education, for research, for the way we set up human institutions, and most important for what counts as a humane way to live and act? Our ideas about what people can learn and should be learning, as well as what they should be doing with what they learn, depend on our concept of learning itself. It is important that we have discovered that learning for the most part is neither rote learning nor the learning of mechanical procedures. It is important that we have discovered that rational thought goes well beyond the literal and the mechanical. -Lakoff, 1987 (Preface) Introduction The above quote is from a 1987 publication by George Lakoff on categorization. He claims: ?it is important that we have discovered that learning for the most part is neither rote learning nor the learning of mechanical procedures? that rational thought goes well beyond the literal and the mechanical.? My claims with respect to analogies echo the findings that Lakoff hails in the preface above. In the 17 years since this publication, how has instruction responded to these important discoveries? What would a response to such findings look like in practice? How should they be incorporated in the classroom? In this chapter, I begin with a critique of a relatively standard approach to analogy-use in the classroom. I then highlight three important implications that this thesis, with its focus on student-generated analogies and the categorization interpretation of these analogies, has for instruction. The first is that student-generated analogies ought to be a goal of science education. The second relates to an appreciation and 171 understanding of the manifold nature of students? minds. And finally, when conceiving of analogies as a form of categorization, questions and goals regarding transfer change. I then present examples from analogies in this dissertation, from the literature and from my own teaching that illustrate these implications in practice. The relationship of these implications to the National Science Education Standards and to calls for a greater diversity in science will be explored. A critique of standard analogy use in classrooms Lulis, Evens and Michael (2004) report on ?How Human Tutors Employ Analogy to Facilitate Understanding? in the context of medical school students receiving tutoring on the heart and its baroreceptor reflex. The tutors in this study are referred to as ?expert tutors? and their practices are being studied for the creation of an electronic tutoring system based on the computational model provided by the Structure Mapping Engine (Falkenhainer, Forbus, and Gentner, 1986). I present this here as an example of what is considered (by some) to be best practices for analogies in education and offer a critique of these practices. All transcript quotes provided below are from Lulis, Evens and Michael (2004). Figure 7.1 (from Scott and Schactman, 2004) below provides a schematic of the heart to help the reader understand the conversation: 172 Fig. 7.1 Student: If I make an analogy of you try to fill a sink with water and you ? Tutor:Try to fill a balloon with water, since that?s what we?re dealing with, a distensible object. Student: Okay. Following this, Lulis et al write: The following structures underlie what the tutor does (as discussed in Lulis & Evens, 2003; Lulis, Evens and Michael, 2003): Structure for the balloon: ? fill a balloon with water ? it will be distend ? the pressure in the balloon increases as it distends Structure for the heart ? fill the right atrium ? the right atrium will distend ? the pressure will increase as it distends The above example demonstrated the effectiveness of the accepted structure mapping approach of connecting new knowledge to knowledge already understood by the student. As a result, the student develops a better understanding of the new concept (Gentner, 1983, 1988; Goldblum, 2001; Holyoak and Thagard, 1995). 173 This is the first analogy mentioned in the article and it is applauded by the authors as effective because of its ability to connect knowledge about the heart to ?knowledge already understood by the student.? The veracity of this claim is dubious ? the student has not demonstrated any knowledge of pressure in balloons ? but the greater point I would like to argue against is the idea of what learning is that is presented in this brief transcript. The tutoring offered in this transcript values content knowledge over the ability to think scientifically: the role of the teacher is to ?correct misconceptions? (Lulis, Evens and Michael, 2004). The primary goal of instruction was to ?develop a better understanding of the new concept? and not to increase the student?s ability to create his own models, evaluate them on his own for their goodness of fit and recommend new models if the fit is poor. The student has constructed a model of the heart as a sink and is immediately cut-off and told, instead, to model the heart as a balloon. This is deemed effective because of the balloon?s structural map to the heart. I argue that this may be counter productive instruction because the student is actively discouraged from pursuing his own analogy. In fact, depending on how his analogy played out, it could be seen as more deeply structural than the tutor?s as it did not rely on superficial similarities, such as distending. The pressure at the tub?s outlet will increase with increasing volume of fluid. This relation between volume and pressure, in fact, is not altered by the tutor?s prompting. That the student has not changed his ?misconceptions? and is still not creating the analogy that the tutor wills is evident in the following transcript from a later session with the tutor as he states that size will: Tutor: We can look at the central blood chamber that means the big veins and the atria together as though they were an elastic chamber. Is that not correct? 174 Student:Yeah, and the heart is the pump. Tutor:Well, let?s stick to this elastic chamber and look at it first more or less in isolation. If you have an elastic chamber what are the things that determine the pressure inside that chamber? Student:Size. Tutor: No. Student:I mean if you ? . I mean ? . Area is one but I gather for the heart ? Tutor:Area of what? Student:Area that ? I mean if you want to know what the pressure is of a gas or well liquids aren?t that ? . We?re not talking about gas, we?re talking about liquids. And liquids aren?t affected by size much because you can?t compress the molecules that much. Tutor:Oh, you mean the volume occupied by the liquid, expansion and condensation of the liquid. No. That?s not an issue. Student: No, because we?re talking about liquids and liquids aren?t affected. Like with gas, besides the container matters a lot ? Tutor:Let?s throw away this atria central venous system and take instead something inanimate elastic stretcher, say like a balloon. Right? What determines the pressure inside the balloon? In this transcript the student again asserts an analogy the heart is like a pump, and is cut- off from continuing with this analogy. Instead, the tutor wants to focus on the ?elastic chamber?-like properties of the veins and atria and why it is best to consider the atria as elastic chambers and not a pump are never made clear. The tutor is not taking advantage of the student?s analogy to try to understand the student?s thinking. Even to the objective of content understanding, the student?s analogy can give the tutor information to help with diagnosis of student difficulties When the student is asked what affects the pressure in the atria (the upper chambers of the heart), he offers size ? which is reasonable and predictable from a sink analogy of the heart. However the tutor clearly has other factors in mind, and flatly responds ?No? to the student?s ideas. But the student, having never understood the failure of his heart-as-sink model or heart-as-pump model, is then clueless as to the ?correct? answer that the tutor desires and seems baffled. Similarly, the tutor 175 misunderstands the student?s reasoning, perhaps interpreting ?size? as being not the volume of blood in the vein, but, perhaps, the volume occupied by a fixed amount of blood. The tutor cuts off the student and provides an analogy to balloons ? which are, of course, filled with the very thing the student just determined as an important factor: gas instead of liquid. And finally, there is a student-generated analogy in which the student proposes that the heart is like a traffic cop. The following session was an online tutoring session and the transcript is a written transcript between the two: Student: Would it be a reasonable analogy to look at the heart like a traffic cop? If it slows down the rate of blood flow (lets fewer cars through) then there will be a backup behind it (a backflow of blood prior to the heart, and therefore an increase in CVP [central venous pressure]) and fewer cars coming through (less blood coming out of the heart and therefore a decrease in MAP [mean arterial pressure]) Tutor:The analogy is OK. But just as traffic jam does not occur because cars back up, the increase in CVP caused by a fall in CO [cardiac output] is not the result of blood BACKING UP. Everything goes in one direction. Student: Well, slowing down would be a better way to put it, then. Tutor:Yes. A traffic jam caused by everybody piling into the same area at once. The authors (Lulis, et al) describe the passage above as follows: ?? an analogy proposed by the student between the heart and a traffic cop. The mapping between these analogs is not correct; the tutor proposes a more suitable analogy between the heart and a traffic jam.? But in what way was the analog ?not correct?? Clearly the tutor found something wrong. The tutor mistook a ?back up? for ?backing up? ? but slowing down for the traffic cop and creating a ?back up? never necessitate a physical reverse of direction. To ?correct? 176 the student?s misunderstood idea, the tutor recommends thinking of the heart as a traffic jam. In summary, the tutor has a concept that he/she would like expressed by the student, and this tutor has a particular analogy in mind for conveying this concept. When the student proposes alternative analogies (which may not even be incorrect), the tutor, concerned with establishing the correct scientific answer in the student and not concerned with fostering the scientific reasoning abilities of the student, cuts off analogy generation. While clearly this is not effective in fostering scientific creativity, it also is not clear that it dislodges any supposed misconception that the student has. Furthermore, the interpretation of the authors, who apply a rigorous structure- mapping technique to analyzing these analogies, suggests that the heart cannot be conceived simultaneously and fruitfully as both a pump, elastic chamber, sink, traffic jam and traffic cop. By their interpretations, the structure implicit in these models is either right or wrong, a misconception or a correct idea. The task of the instructor is to give the student the correct analogy for the purpose of correct conceptual understanding. I would like to note that the instruction described above for implementation in an electronic tutoring system is described not by the creators and proponents of structure- mapping, but is instead one interpretation of how structure-mapping may be employed in the classroom. A more fruitful manner in which to employ the concepts behind structure- mapping is case-based reasoning, and the merits of this approach are detailed by Gentner, Loewenstein and Thompson (2003). The approach described in that article focuses on ways in which one may foster analogical retrieval and transfer in the students, as opposed 177 to content knowledge. Yet one message is still the same: the students must be told the analogical cases in the first place before abstracting from these cases on their own. As an alternative to instruction by analogy, with the focus on misconceptions and correct ideas, I argue instead for instruction that fosters analogy and encourages the students to create their own analogies and determine the merits of them. With an appreciation for the role of chains of analogies (analogy ?hopping?), the initial analogy?s merits are not in the conceptual correctness in a structure-mapping sense, but instead the analogy is meaningful for the activation of resources: schemas and cognitive models that may help them negotiate a more meaningful analogy and understand the ways in which various analogies are applicable, so that the heart can be conceived of as a pump, chamber, sink, traffic jam and traffic cop. Implications for instruction Students ought to generate their own analogies Studies on creativity ? creativity in general and creativity in science ? have shown that the essence of creativity is to be able to view a situation or an object from two different frames of reference, or two ?unrelated matrices of thought? (Koestler, 1964). This is sometimes referred to as restructuring. Restructuring, thus, is often viewed as being able to see a problem in a ?new way? that is fundamentally different. However, defining creativity in this way merely begs the question of what constitutes a ?new way,? a ?different frame of reference,? or ?an unrelated matrix of thought??? A new perspective is defined here as re-representing an entity or a situation from one ?ontological? tree of concepts and categories to another ontological tree of concepts and categories? -Chi (1997) In this thesis, I have argued that analogies are assertions of categorization that violate expected categorization. In short, analogies are powerful precisely because they do this 178 thing that has been identified as the essence of creativity. It is not a leap, then, to suggest that a goal of education should be to encourage and foster creativity by teaching students to generate and elaborate analogies. Furthermore, using analogies is part of what it means to do science. ?In studies of the work in molecular biology laboratories, Kevin Dunbar found that the most creative and productive labs showed a high frequency in the generation of analogies and the sustained collaborative elaboration of analogies? (Kittay, 1997 p. 400). In particular, Dunbar found that when formulating hypotheses scientists rely on ?far transfer? analogies: analogies that rely on structural and not superficial similarities. Given that doing science, then, entails generating and elaborating analogies, science classrooms should encourage the generation and elaboration of analogies. Of course, analogies are frequently used in the classroom. In a recent article by Richland, Holyoak and Stigler (2004), they report on an in-vivo study of analogies in eighth grade mathematics classrooms. As with Dunbar?s finding, Richland et al found that analogical reasoning is quite prevalent and even far transfer analogies are not uncommon. However, it was not the students but the teachers who generated the vast majority of analogies in their study, and these analogies were aimed at achieving goals relating to conceptual understanding: getting students to solve problems correctly or understand why they are applying a certain method. These analogies, then, are not indicative of students? use of analogies in the classroom. Even more troublesome is that the concerns raised in Richland, Holyoak and Stigler?s (2004) article were not regarding this fact. Instead, the concerns questioned whether or not students were able to interpret the teachers? far-transfer analogies. Teacher-generated analogies are important and can 179 play a role in encouraging student-generated analogies; but they should be responsive to the students? ideas and not solely for the purpose of imparting knowledge. These findings and the concerns are representative of the pervasive focus on the facts of science as opposed to the creative inquiry that is involved in doing science, a focus reiterated in classrooms by a reliance on textbooks and testing. The question that tests and textbooks answer is: how can I get my students to know x, and how can I determine whether or not they have learned x? Similarly, cognitive science literature on analogies (such as Gentner & Gentner, 1983; Clement, 1983; Glucksberg and Keysar, 1990; Gibbs, 1992) consistently focuses on participants? abilities and processes regarding the interpretation of analogies and only very rarely (Hofstadter, et al, 1995) the generation of these analogies. The question that is unanswered by these textbooks, tests and studies is: how can I help my students learn how to learn? How can I evaluate whether or not they will be creative scientists? How can I help them to create their own theories? Of course, one might expect that presenting students with carefully constructed analogies will aid them in constructing their own analogies, and so the teacher, as presenter of analogy, is modeling a behavior for the students that they may in turn adopt. But such analogies are not responsive to the schemas that the students have and may seem disconnected from their own lives. Furthermore, simply modeling behavior for students without giving them time to practice that skill on their own will not always result in the students adopting that behavior. There must be space for the creation and elaboration of analogies by the students. I will detail in a later section what this might 180 look like in practice. First I highlight implications from my research on the interpretation of student-generated analogies. Expect variability and multiple analogies To borrow again from Lakoff?s quote that introduces this chapter, ?It is important that we have discovered that learning for the most part is neither rote learning nor the learning of mechanical procedures. It is important that we have discovered that rational thought goes well beyond the literal and the mechanical.? The discoveries that Lakoff refers to are discoveries in linguistics in general, and categorization in particular. To this, I would like to add that it is important that we have discovered that children ? even young children ? can and do create significant, structural, ?far transfer? analogies. It is important to recognize the ability of students to shift representation of the base in analogies. It is important to recognize that analogies often appear in multiples, that they have a strong similarity to categorization, that they can be used to make claims of structure, of epistemology, and of ontology. In what way are these findings important for education? Primarily it is an implication for education research. First, if we value the generation of analogies it is important to understand the cognitive work that analogies do. Far from what structure- mapping suggests, generated analogies are not simple pairwise projections from a base to a target and learning, as Lakoff identifies, ?is not the learning of mechanical procedures.? That is to say, applying the algorithm of a structure map is not the heart of analogy and while it may promote content knowledge acquisition, it does not necessarily promote creative and insightful reschematization. The structure-mapping application of analogy limits the power of an analogy ? it can only hold particular inferences, and those 181 inferences must come from a structure that exists in a stable, fixed representation in the single base. Analogies are powerful not because of a projection from a single known phenomenon (the base) onto an unknown or misunderstood phenomenon (the target), but because of their ability to completely change the categorization of the target. And categories, because of their basis in a particular cognitive model, can make powerful claims on the target. These claims are not limited to what the base alone conveys, but, more abstractly, what the category and its associated cognitive model imply. Furthermore, because of this it is not imperative ? or even reasonable to expect ? that students reason with conceptually (that is, structurally) isomorphic analogies. Rather the analogies may enable other students to access alternative models and follow chains of analogies to arrive at an appropriate understanding. A second claim is that, if we value analogy generation, we ought to know where to look for it. Young children have been described as unlikely to create analogies of ?far transfer? (for example, Carver, Price and Wilken, 2000). I will take issue with the concept of ?far transfer? in a later section, but for now it is important to note that second graders were able to compare magnets to clay and electricity. Fifth graders compared a swimming pool to space, a cup of water to a toy cat swinging in a basket, and running with keys to falling off of your bike. There is not, then, a particular age in schoolchildren when one should not expect and encourage analogy generation from students. The sophistication and facility with analogy surely increases with age, but analogy ? even far transfer analogy ? is prevalent among students from at least first grade on. 182 A third claim that has implication for instruction is the claim that this research makes on the ontology of mind. Not only are the concepts that are being employed in analogy the concretization of a set of activated schemas, but the concepts themselves are variable. A concept can be employed in an analogy for its epistemology, its physical behavior, or its general ontology. A concept can shift representation, as with money being used to represent the ?hard? ontology of currency or the ?fluid? ontology of net wealth. For this reason, science education researchers should recognize the variability of student reasoning: the base of an analogy is not a single, unitary concept that is fixed in the student?s mind, but highly variable. Teachers need to allow students to express their senses of a concept, to identify the cognitive models they are employing in defining this concept and allow for a shift in this representation. (Clarifications of these ideas are provided in the section below on these implications in practice. Significant to this claim is that the initial analogy does not need to be conceptually correct to be generative of meaningful science ? conceptually and epistemologically.) A reconsideration of the idea of transfer Finally I would like to call into question the ideas behind ?transfer? ? a holy grail of education. Transfer is described as ?the ability to extend what has been learned in one context to new contexts? (Bransford, Brown, & Cocking, 1999). Laboratory-based studies that address whether or not students transfer a particular technique or theory from one domain onto another have demonstrated that far transfer ? transfer in which there are few superficial similarities ? is difficult and rare. ?Near? transfer, in which there are more feature similarities between the base and the target, are more common but not consistently achieved either (Holyoak and Thagard, 1989). In the study reported above 183 by Richland, Holyoak and Stigler (2004), it was found that, unlike in the cognitive science laboratory settings, analogies teachers present in classrooms are often far transfer analogies. Dunbar?s research in science research groups found this as well ? though the majority of analogies were within-domain, far-transfer analogies played a significant role. Similarly, my findings in science classrooms and discussions show that instances of transfer, as measured by analogy use, are not difficult to find, with far transfer demonstrated across many different ages of students. But I would like to call into question the very idea of far transfer as a meaningful distinction. In a category framework of analogy, one would not expect far transfer to be as difficult if the base of the analogy is a category prototype. Furthermore, near transfer, because it does not require a re-categorization of the target, is not an analogy in the sense that it does not shift ontology ? it is routine categorization. Again, this is a choice of definition but one that can provide a more formal model for what is meant by transfer. Perhaps the idea behind transfer that we should be focusing on as educators and researchers is the ability for students to draw analogies that re-categorize the target from an expected or automatic categorization to a novel one, the ability to make inferences with this new categorization, and the ability of students to identify meaningful and prototypical choices for the bases of their analogies. Focusing on whether or not the base of the analogy shares superficial features with the target misses the point of analogy: the selection of a prototypical member of a category to serve as a base in expressing a reclassification of the target. When a student is asked what will happen to keys if you drop them while running, is the analogy of dropping a rock from a bus ?near? or ?far? transfer? How would that compare to, say, a student drawing an analogy to walking and dropping coins? The features of the 184 second analogy are certainly ?nearer? to the base, and dropping coins while walking surely happens far more frequently than rocks are dropped from buses. But in discussions with students the first analogy (or similar analogies) is far more frequent than the second (which I have never heard). How, then, can we claim that far transfer is hard and near transfer easy? Instead, I argue that transfer is better understood in terms of a change in cognitive model, with prototypical instances as more accessible instances of a particular cognitive model. Implications for instruction in practice Examples from transcripts If these implications are taken into account in a classroom, what will that look like? The transcripts peppered throughout this dissertation prior to this chapter give an idea. Throughout this dissertation are analogies in classrooms that are constructed by students and by teachers who are responsive to those students. To detail analogy generation by an instructor that is done in a responsive manner, consider the transcript presented in Chapter 1 and contrast the use of analogy here with that by the tutor at the introduction of this chapter (transcript 1, lines 53 ? 71): Lea: ? the pan is more dense so they?re able to slide across it like they can ice skate across the [inaudible] here. So that?s why they move around more ?cause it?s more dense so they can slide across it more and the Styrofoam is less dense and so they get stuck in it. Like so they can?t move as much. Instructor: Lea I want to add ? I think you?re sort of what I when I hear you talk I?m thinking of like, pouring water into a sponge versus pouring water onto a hard surface. [Lea: Yeah.] Like this sponge is actually less dense and there?s room for it to absorb the water and the you know if you pour it onto something hard there?s no room for it to absorb. But Christie ? I mean this is an interesting thing you guys are both thinking that density is important but one of you is thinking that more density means one thing and one of 185 you is thinking more density means the other thing. Is that is that ? am I right? [Christie: Yeah.] And in lines 113 ? 121: Lydia: I was going to say I think the pie plate is more dense but I do think that it?s inside not outside because if there?s more space to travel then the molecules can?t get from one space to another easily but it?s all [inaudible]. Instructor: Oh so it?s like stepping stones [Lydia: Kind of.] like in the Styrofoam it?s really far to the next stepping stone so it?s like can?t get there I?m stuck here. [Lydia: Right] but in the metal the stones are really close together so I can kind of walk across. [Lydia: Yeah.] In addition to creating a classroom in which students are encouraged to construct their own models and explain these with analogy, the instructor constructs analogies as well. However, rather than constructing analogies for the motion of charged particles and presenting them to the class, the instructor constructs analogies that are responsive to the ideas from the students ? elaborations on their ideas (?oh, so it?s like stepping stones?) as opposed to contradictions to their ideas or even unrelated to their ideas (as was the case in the tutor?s analogies presented above in the previous section). Examples from the literature Another example of responsive use of analogy in the classroom has been detailed in May, Hammer and Roy (2004). The class is considering how earthquakes happen and one student constructs a lava/pressure model of earthquake: Skander: That?s what I mean. A rock could ? like, the volcano is this big [motions with hands] and you?re on this side of the ground, a rock could go in, and pretend like, pretend the lava is water and the giant rock is a cube [Teacher: okay] it goes up and since it?s blocked the ground has to shake which causes it to crack open so it it?ll actually like go up farther. Teacher: Okay, so you?re ? Skander: So it?s like you?re actually flooding the cup of the water. 186 Teacher: And so the rock acting as the ice cube is flooding the lava so it has to come up and go out? Skander: It doesn?t have to, it just makes the ground come, it just needs space to go up. It?s just causing it to shake and crack open. Although this analogy is suggesting a mechanism that is incorrect for understanding earthquakes, the teacher does not contradict Skander (as the tutor does at the beginning of this chapter) or call on a different student, but allows the student to continue with the generation of analogy. In the following section I follow an example from my own teaching, in which I detail how incorrect analogies can play out in the classroom. An example from my own teaching Here I present an overview of a week-long conversation in a high school science class regarding why the sky is blue. This conversation was not recorded; data comes from notes and photographs of the blackboard, where ideas were collected. I was a co- instructor of this course and I did not refrain from interjecting my own analogies for the students. The class is at a state funded summer program for ?academically and intellectually gifted? high school seniors. There are 27 students in this class. Most of these students are from public schools in small towns and rural areas. At the time of this conversation, the students had been in school for four weeks. A typical day began with either a ?Fermi Question? (a question requiring students to answer a question numerically for which there was not enough information to determine the exact answer) or a ?Science Talk? question (a more conceptual type question, generally about a physics concept). By the end of the summer students pose and answer their own questions as a class. In the beginning of the fifth week, the question was raised, ?Why is the sky blue, and why does it get darker the further up you go (like in an airplane)?? In groups of 4 they addressed 187 this question, and, as the teacher, I instructed them: ?Don?t just say ?because of the atmosphere.? Be sure you say how you think the atmosphere creates blue.? (Not a direct quote.) As they worked in groups, my co-teacher and I circulated around, talking with each table and having them sketch their ideas on dry-erase boards to share with the class. After about 20 minutes, I addressed the class as a whole. I had noticed that some tables were thinking of the atmosphere as a filter, and others as a prism. I asked if all of the groups had one of these ideas, or were there more? Between the six tables, there were the following ideas: ? The atmosphere is undergoing atomic emission. ? The atmosphere is like a prism: different angles to that prism see different colors. ? The thickness of the atmosphere somehow matters. ? Energy loss in the atmosphere creates a reddening of the light. (The ?filter? theory was discarded early on by a table that recognized that this would block out every color except blue.) In addition to these initial, whole-group theories, other theories were proposed by individuals: ? Thin film interference in the layers of atmosphere preferentially select blue light. ? Distance from the sun matters. (A correlation between planet colors and the order of colors in the rainbow, the class never seriously entertained this theory.) ? Reflection from the blue ocean creates a predominantly blue sky. (Quickly discarded this theory.) Perhaps because of the charisma of the proponent of the theory, the ?atomic emission theory? was adopted early on as a theory to consider in depth. The students recognized that this theory had to account for red sunsets and red pollution, green flashes and green 188 tornado skies. It had to account for the colors of skies on other planets (both of my classes that addressed this question became very focused on the color of other atmospheres) and for the sailors? aphorism: ?Red skies at morning, sailors take warning; red skies at night, sailors delight.? One student noted that skies seem a more deep or crisp blue in the winter, another that dawn was not as red as dusk. After lunch one day, students came in to tell me that the sky is light blue ? almost white ? close to the sun and a darker blue away from the sun (as drawn below). Fig. 7.2: Description of shades of blue in the sky In negotiating these constraints, the students could incorporate some ideas from atomic emission, but not all. The theory grew to be an atomic emission theory combined with a weather component to explain other colors and a filter component to block ultraviolet light. A question that was could not be addressed by this theory concerned why white paper does not look blue. After too many ad hoc components were added on to the theory, the students as a class decided it could not be correct. (Questions and comments addressing the ?atomic emission theory? are in the figure below, a snapshot of 189 one blackboard. All student comments and questions were noted for the whole class on the blackboard, in addition, many students took notes and represented their ideas for the class on their group?s dry-erase boards.) Fig. 7.3: Blackboard notes of class discussion We then revisited theories they had mentioned on the first day of discussion. In writing them on the board, I asked one student about his thin-film theory. He commented that it was ?stupid? and we shouldn?t consider it. Knowing that this student had been questioning in the past how bubbles get their oil-slick-like colors, I pressed him for his rationale in creating the theory. The bubbles were mentioned and I pointed out, using his experience with bubbles, that really what all of these theories have in common is that they are a way of using white light to get colored light. Bubble ?juice? itself is clear and has no color, nor does a prism or neon gas (a model for atomic emission) or ?red shifted? white light, and white light bouncing off of a blue surface will then appear blue, even on ?colorless? white. All of these systems have no apparent inherent color and yet they all have a mechanism by which they attain color. More importantly, the students recognized 190 that these mechanisms were inherently different, so that a prism model was not the same as an interference model or an emission model or a red shift model. At this point I note several ways in which I, as a teacher, was incorporating the implications for instruction mentioned above: my rationale in structuring the course in this way and my interpretation of the students? comments. First, I know why the sky is blue and could easily have delivered a 10-minute lecture on the topic, expeditiously explaining why the sky is blue ? incorporating analogies if helpful. (Although some questions they brought up are ones I had never considered and would have been hard pressed to answer!) Moreover, I know that the students do not know enough physics to correctly answer the question of why the sky is blue. The pattern of dipole radiation that is responsible for our blue sky is beyond the scope of a high school physics class, although the basic story of scattering is one that they could reason about and understand. My reason for asking the students to develop their own models reflects my contention that education should encourage students to learn how to create their own models and draw their own analogies. I also believe that it is possible to address this question scientifically even if one does not know enough science to arrive at the ?correct? answer ? for though Newton did not know enough about light to understand reflection he addressed these questions in a scientific manner and arrived at questions that proved important to later research. At any point, I could have posed questions to them that would have poked holes in particular theories, but I chose to allow the students to find these themselves, as part of what it means to do science. Second, I did not assume that the analogies arose from a pairwise analysis of target and base: initial analogies were identifying ways in which one can get color from 191 colorless things; the analogy springs to mind before the structures (in a ?structure mapping? sense) can be evaluated and checked; this evaluation was done in large part as an entire class and was not part of the analogy process for any single individual. These analogies, the initial models proposed by the students, echo the analogy process that Miranda used (in Chapter 4). In the same way that the overturned cup of water is not always like an overturned cup of water ? at times it is much more like a toy cat swinging in a basket, so too is air not always like air: at times it is more like a prism, a neon sign, or a hologram. An understanding of the analogical base as a fixed structure cannot expect and understand the generativity of other analogies. Expecting the student might draw a series of analogies, finding her way from that first idea to another and to another, a teacher would not be so concerned that the first analogy be correct. If we think of analogies in target-base pairs, that first mapping would be critical. But if we think of analogies as activation of different sets of resources, that first analogy could lead to a second. In fact, few students knew how a prism worked ? the deep structure of the analogy they were proposing, or details about atomic emission. Discussions of how these things worked were figured out as a class at times, with a few brief (five minute) lectures from me. These explanations and discussions evolved into new models based on new analogies: an ant/giraffe model of light moving through media that explained why red is less impeded than blue, a ?marching band? model of refraction to explain why light bends, and a trombone/piano model to explain the difference between a ?chord? of colors and a pure color. From this arose new questions: is our blue sky an ?average? color or a pure color? Shouldn?t we see a green sky at times if our atmosphere is a prism? If blue is ?impeded? in the atmosphere and so gets to us later, how does that affect the colors that 192 we see? Representations of air, prisms and bubbles are all variable, so that they may belong to similar categories (things that are colorless and yet have color) and distinct categories. Following negotiations of several candidate theories over a five-day period, the class settled on a ?prism? model for creating blue skies. They still had a two questions: why we don?t see a green sky between the blue day and the red night, and by what mechanism do long wavelengths bend less than short ones (we had an ?ant/giraffe? analogy, but it seemed more mnemonic than a model). But these questions aside, the class was relatively confident in their model and asked for the ?right answer.? I then read them a passage from the New York Times? Science Tuesday section. (Coincidentally, this article on colors in nature was published the day before I had promised to tell them ?the answer.?) The passage reads as follows (Angier, 2004): Another type of structural color results from the incoherent scattering of light, also known as Tyndall or Rayleigh scattering. The sky is the most renowned example of such scattering at work. Sunlight and its complete spectrum of radiation falls on the atmosphere, a diffuse wilderness of particles. Most of the light rays are too wide of wale to be impeded on their journey earthward, but blue light is so short-waved that it invariably meets a molecule it cannot ignore and is scattered across the sky. Following our five-day discussion on why the sky is blue, this passage (?the answer?) was met with puzzlement. The students were upset that it said nothing about green, or why sunsets are red. The phrase ?too wide of wale to be impeded? was written off as utterly incomprehensible ? how can something be too wide to be impeded? Length, not width, was the determining factor in our discussions of blue skies. In our discussion following the reading, the students determined that the passage was vacuous. In particular, there was no reason for them to believe this model over any other model; the 193 explanation did not address any of the questions that they still had; the explanation did not express why other models fail; and it never explained that the scattered light had to eventually reach your eye to be seen ? a hang-up that had troubled many students in our discussions. Rather, it seemed to suggest that if there is blue light scattered among the atmosphere we will necessarily see that atmosphere as blue. The blue-sky explanation from the New York Times still uses analogy, albeit quite loosely, as a tool for conceptual understanding. Describing a photon as ?wide? is a metaphor: photons do not have much physical extent in the direction perpendicular to their propagation. But I am not primarily arguing against teaching via analogy because the analogy that was provided by the article was provided was not one that the students could make sense of; rather, by having the students build their own models by drawing from analogies to systems with which they were familiar, and then exploring why they hit on these models and negotiating the implications of these models, created a far richer understanding of the material, developed in them a sense of what it is like to ?do? science, and allowed the students to quite realistically model the interactions and discussions one would find in a research group. 1 Finding analogies in the classroom What kinds of discussion topics foster analogy generation? As noted earlier in the thesis, they are negative assertions ? such as a cup of water that doesn?t spill, colorless air that looks a particular color, or physics problems that cannot be solved from first principles. 1 There is not an explanation that is detailed and coherent enough about why the sky is blue that will enable students to understand why other models fail. Nor can a detailed explanation help students learn how to create theories and models on their own. 194 Lakoff (1987) notes that ?but? can often be used to identify cognitive models. For example, in the phrase ?She?s a mother, but she works,? the ?but? acknowledges that there is something about ?motherhood? that is (culturally, at least) at odds with having a paying job. Similarly, all of the topics above have that ?but? quality to them (I wrote them in a way to highlight this aspect, of course). In some way these scenarios do not have the expected outcome, meaning that the topic is in some way at odds with an idealized cognitive model. And so, in order to make sense of the scenario in a scientific way (meaning coherent with known phenomena and experience), the topic must be situated in a different cognitive model. And, since cognitive models give rise to categories, to situate the topic in a new and appropriate cognitive model this topic must be granted membership into a new category. The category has a prototype and this prototype is selected via an analogy to demonstrate the new category and its associated cognitive model. Many, but not all, of the topics above were chosen for their ability to be reasoned about in terms of ?tangible? ideas, which is a part of analogy 2 . Another element of analogy is the change of categorization. Science, and physics in particular, is rife with paradoxes 3 , and these paradoxes can be resolved within science. One tactic I have in teaching is what I refer to as the ?what?s weird.? When a student performs an experiment or makes an observation and thinks, ?that?s weird,? I tell them to stop right there and ask: 2 In my class, we were having a discussion of Kuhn?s Structure of Scientific Revolutions and by modeling theory building we modeled paradigm shifts. The focus was not on analogies (though doubtless my interest in them fostered their construction). 3 My graduate quantum mechanics professor, Dr. David Boulware, lectured one day on the redundancy of the phrase ?apparent paradox.? In physics, he claimed, all paradoxes are only apparent and can be resolved. 195 why is this at odds with what you would expect? Identifying the story that you expected to take place and recognizing the rationale for that story allows you to understand the schema that you were applying and other examples of that schema. Then the students are asked to ?make sense of it.? How can you tell this story in a way that the initially unexpected outcome makes sense? In doing this, analogies are frequently generated. The National Science Education Standards Another question I would like to raise and answer in this chapter is whether these implications for instruction are consistent with the National Science Education Standards (NRC, 1998). In fact, the Standards make no explicit reference to encouraging students to generate and critique their own analogies. However, analogy generation and use is a powerful tool for addressing many of the goals set forward in the National Science Education Standards, in particular those involving the ?abilities necessary to do scientific inquiry.? These are: ? Identify questions and concepts that guide scientific investigations ? Design and conduct scientific investigations ? Use technology and mathematics to improve investigations and communications ? Formulate and revise scientific explanations and models using logic and evidence ? Recognize and analyze alternative explanations and models ? Communicate and defend a scientific argument As I have argued, student-generated analogies address these goals: they are a key part of how science happens; they often arise when experimental results clash with expectations ? a fruitful place to identify questions and guide investigation; they can be the basis for conducting an investigation and constructing a model; the evaluation of analogy is deeply 196 tied to logic and evidence; and analogies are routinely used by scientists in communicating and defending their scientific arguments. The case for diversity in science A final claim that I would like to make is more an implication for science ? the enterprise and industry ? than science education, though the two are, of course, related and to change the enterprise and industry of science one must have educated scientists to effect that change. But I hasten to add that the causes for such a lack of diversity among scientists are perhaps only related to education insofar as education is influenced by the culture of science and the culture at large. Therefore these implications should be not only for instruction but an argument to the culture of science, as any lasting change must come from the source. As noted in the chapter addressing the history of science, our discoveries ? the things we pay attention to, notice, expect and explain ? are not recognized objectively. Rather, the theories we create with our science are analogies to the stories we tell with our lives. Though the technology and techniques necessary to identify cellular structure ? membranes ? in the nervous system had existed for years, they were not discovered until the surrounding culture developed a story of membrane-like countries ? dividing up the landscape into distinct separate self-contained units. Though electrical phenomena had been studied for years, the nervous system itself could not be understood until the telegraph was invented and gave us the causal story behind impulses in nerves. To follow an analogy presented in chapter 6, ?rabbit ears? in a drawing of a duck are recognized only by people who have seen rabbits. The conclusion we must reach, then, is that people with different stories will notice different things, make different discoveries 197 and have different theories about these discoveries. Their analogies will be different because their stories are different. And surely a diversity of discoveries and theories are a benefit to the enterprise of science. The more that the culture of science, and the culture at large, allow for a diversity of scientists, engage with and allow a diversity of interpretations and theories, the far richer our science will become. Conclusion ?The essence of creativity the essence of creativity is to be able to view a situation or an object from two different frames of reference, or two ?unrelated matrices of thought? (Koestler, 1964).? And analogy, as this thesis has argued, is an assertion of categorization that places the target in a new or unexpected category. Instruction that fosters analogy generation, then, is instruction that fosters creativity. Furthermore, analogy generation is a crucial part of what it means to do science. This cannot be taught by the careful selection and presentation of well-vetted analogies, but instead by encouraging students to generate and negotiate their own. Classrooms that focus on student reasoning and incorporate the creation of analogy rather than teaching by analogy encourage students to be creative and scientific. In doing so, many of the benchmarks in the National Science Education Standards will be addressed. Furthermore, an understanding and appreciation for the role of analogies in science, and the basis of these analogies in the schemas that we bring to our lab benches, can only call for a greater diversity ? cultural and gender ? in our scientific community. 198 Chapter 8: Summary & Directions for Future Research Introduction You fight your superficiality, your shallowness, so as to try to come at people without unreal expectations, without an overload of bias or hope or arrogance, as untanklike as you can be, sans cannon and machine guns and steel plating half a foot think; you come at them unmenacingly on your own ten toes instead of tearing up the turf with your caterpillar treads, take them on with an open mind, as equals, man to man as we used to say, and yet you never fail to get them wrong? The fact remains that getting people right is not what living is all about anyway. It?s getting them wrong that is living, getting them wrong, and wrong and wrong and then, on careful reconsideration, getting them wrong again. That?s how we know we?re alive: we?re wrong. -Philip Roth, American Pastoral When I began my study on analogies, I was interested in a study on negative analogies: that is, the places where our analogies are wrong, when the target and the base of our analogies don?t quite match, where these mismatches occur, and what that tells us. I was asking this question having recently sat in on a course in literary theory ? a field where scholars have argued that we define our terms and our stories negatively: by what they are not instead of by what they are ? and noticing parallels between this idea, based in literature, and my experience in the lab and as a physics teacher. However, the lack of information on student-generated analogies shifted my focus from negative analogies to analogies in general, establishing what analogies are and what kinds of claims they make. Following a summary below, I begin the consideration of directions for future research with a discussion on the literature of differ?nce and the relationship between this idea and the idea of a negative analogy. I then present a consistency between these ideas of difference and negative analogy and the framework behind student-generated analogies 199 presented in this dissertation. Finally, I conclude with suggestions of a direction for future research ? first with respect to negative analogies and then analogies, categories and science education. Summary In this dissertation, I began with the argument that student-generated analogies phenomenologically have the properties that have been recognized in categorization research: multiple members, family resemblance, constructed bases with multiple possible representations, and far transfer analogies. Furthermore, these properties are neither predicted nor explained by models of analogy that focus on recall of a base and then an extrapolation of a structure or schema from that base. When considering an ontology of mind that allows for this phenomenology, I have argued that a schema- theoretical model of mind accounts for these properties: it attributes schemas (p-prims, scripts, and cognitive models) as the building blocks of mind that become activated and then select and construct concretizations. It has been argued (i.e., Lakoff 1987) that our categories are defined within and derivative of our schemas, and I argue that the base of an analogy is such a category ? a representation, constructed in the moment, of a set of schemas. The assertion of an analogy is an assertion that the target of the analogy belongs to the category represented by the base, as opposed to simply a match between the target and the base. Under this ontology, it becomes possible to sketch a definition of analogy that differs quite fundamentally from similarity ? a definition lacking from other models of analogy. Analogy in this definition becomes a deliberate cognitive move that acknowledges the presence and possibility of two distinct cognitive models and privileges one over the other. 200 In considering the directions for future research, I would like to begin by considering this final point above: analogy as a negative assertion and a move from something ? the cup of water is not like other cups of water, a beanbag dropping is not like throwing a rock from a bus, motion of electrons in a dense media is not difficult like the motion of a person through a dense crowd, and solving angular momentum problems in physics is not something to be done from first principles. This idea of defining and understanding concepts by what they are not echoes claims from literary analysis, which in turn raises questions for future research. Negative analogies Literary analysis and differ?nce At the beginning of the 20 th century literary analysts were dedicated to identifying similarities between texts ? this script that defined a story. Their work focused on determining the story on which all stories were based ? thereby reducing all particular stories to the general. Jung (1969) explored the relationships between all myths and rituals. Psychologists (among them Fromm, 1957) developed a theory of fairytale in which all fairytales are variations on a single fairytale theme. But in the 1950?s Roland Barthes began to stress the importance of recognizing how things are different ? that the theme is not the meaning, but the variation on that theme. Barthes summarizes the task of analysts of narrative in reducing all stories to one model as a: task as exhausting as it is ultimately undesirable, for the text thereby loses its difference. This difference is not, obviously, some complete irreducible quality (according to a mythic view of literary creation), it is not what designates the individuality of each text, what names, signs, finishes off each work with a flourish; on the contrary, it is a difference which does not stop and which is articulated upon the infinity of texts, of languages, of systems: a difference of which each text is the return. A choice must then be made: either to place all texts 201 in a demonstrative oscillation, equalizing them under the scrutiny of an in- different science, forcing them to rejoin, inductively, the Copy from which we will then make them derive; or else to restore each text, not to its individuality, but to its function, making it cohere, even before we talk about it, by the infinite paradigm of difference, subjecting it from the outset to a basic typology, to an evaluation?. (Barthes/Miller, 1991) Barthes theory stems from a tradition in semantic theory developed some 40 years earlier. In the 1910?s Ferdinand de Saussure developed a theory of ?differ?nce? whereby words (or rather ?signs? ? the sum total of information from gesture, word, tone, etc.) get their meaning not from a simple one-to-one relationship with the external world, but ?one unit has value within the system because it is not some other unit within the system? (Tyson, 1999). Concepts are defined in opposition to other concepts. Laura Otis, whose work was reviewed when discussing the history of science, comments on noticing the following parallels between Saussure and science, retelling her experience in a lab that studied visual perception: I was a biochemist, a mere visitor to the lab, but I learned an important lesson that night. The eye, and the regions of the brain that interpret visual information, respond only to changes, to borders between light and dark. There are cells that fire only when a bar of light moves horizontally, and cells that fire only when it moves vertically? there are no cells that respond to a uniformly illuminated screen, with no movement, no edges, and no borders? Fresh from the lab, I learned the same lesson in Jonathan Culler?s introductory course on literary theory. Explaining Saussure?s idea of how words were paired with objects, Culler proposed that we define concepts not based on what they are, but on what they are not. When defining something, we typically compare it to something similar and then, like the eye, focus on the way it differs from the concepts most closely related to it. A cow, for instance, has four legs like a horse, but it is fatter. There is no natural match between a word and the thing it represents; no positive assertion of a thing?s identity, just as there will be no firing in response to a blank screen, even when it is brightly lit. Like our visual system, we create meaning only through the differences we perceive and the boundaries we believe are present. (Otis, 1999 p. 1?2) 202 Otis, a professor of comparative literature, presents this story at the beginning of her work on membranes to note two things: one, she is interested in boundaries ? this book explores the concept of membranes in political and scientific climates, and, two, that the boundary ?between the humanities and the natural sciences as a another boundary arbitrarily drawn.? (Otis, p. 3.) I present it here to revisit the idea of the negative assertions that are implicit to analogy. Negative analogies I have argued that analogies involve more than just similarity, but also dissimilarity ? they dislodge the target from its expected categorization and schema and place it in another one. The claims of Barthes and Saussure, and reiterated by Otis, suggest that perhaps the most significant function of the analogy is the ?dislodging,? negative part of analogies and the contrast the analogy highlights: what is crucial is not the claim that a is like b but instead, implicit in this claim, that a is not like c. However, the idea of differ?nce also suggests that there is something negative inherent in the ?a is like b? claim ? for Barthes claims that ?[reducing all stories to one model is a] task as exhausting as it is ultimately undesirable, for the text thereby loses its difference.? It is this idea that I suggest as a significant area for future research. When drawing analogies between two cases, the significance comes not only from the similarities between the two compared cases and the difference between the target case?s expected and asserted schemas, but also the differences between the two compared cases. The value assigned by the analogy also comes from the difference between the items that are asserted to be members of the same category. It illustrates what is essential 203 to the category as well as identifying what is unique about the phenomena. Furthermore, as Barthes (1991) notes, this difference is not what designates the individuality of each text, what names, signs, finishes off each work with a flourish; on the contrary, it is a difference which does not stop and which is articulated upon the infinity of texts, of languages, of systems: a difference of which each text is the return. By paying attention to how our target differs from the base, and doing so in a dynamic way, we set up a dynamic science ? one that evolves, ?making it cohere, even before we talk about it, by the infinite paradigm of difference, subjecting it from the outset to a basic typology, to an evaluation?? (Barthes/Miller, 1991). Without negative analogies we?re just doing the same thing over and over ? we have a set of solved problems and the business of science is to recognize how new phenomena fit within these solved problems, but taking into account the negative analogies, we?re changing ? adapting our categories, extending and limiting them. Below I present a brief sketch of research and questions concerning negative analogies ? that is, the places where analogies are not correct but the analogy overall is still accepted and the base is understood within this new cognitive model. These analogies shift our understanding not only of the target ? because it is placed into a new, unexpected schema ? but also the base of the analogy, because elements that seemed inherent to that base and fundamental to the schema become tangential. At the time that I first came across these readings by Barthes and Saussure, I had just left a condensed matter laboratory, where I spent most of my time writing computer programs to interpret data on the structures of sandpiles (Atkins, et al. 2001). Much of programming ? at least in the sciences ? involves taking a piece of code that is in some 204 fundamental way the code that you need (usually from Numerical Recipes in C), but not quite, and modifying it. The original programs often bear very little resemblance to the final program ? but the core of the idea remains. How do programmers choose a particular structure for their programs? How do they analyze the strengths of these particular lines of code, know what to modify and what to keep? Rachel Scherr, as part of her doctoral work on relativity, created a set of tutorials that leads students to arrive at the relativity of simultaneity. The context of the tutorial is two relativisitcally related reference frames, each of which is observing a single tape player in a scenario that is contrived to give students the following options: either the tape player is seen by one observer to play and another observer to remain off, or simultaneity is relative. As Scherr (conversation) claims: ?If you have to choose, I?d much rather give up simultaneity than allow the tape player to both play and not play.? It is this determining of what is essential that lies at the heart of much of scientific discovery ? do we ?give up? simultaneity in order to preserve causality? Which is more fundamental to our science if we can?t have both? Do we allow popes to be bachelors or do we refine our definition of bachelor? Which is the more primary? Are quasi-crystals crystals? Are viruses organisms? Negative analogies in physics In ?Analogy as the Central Motor of Discovery in Physics,? a talk given by Hofstadter at the Ohio State University (2003), Hofstadter argues that analogies are a driving mechanism for discovery in science. He details the progression of ideas from a literal field with hills and valleys, to assigning the gravitational potential to every point in space ? a scalar field. And from there scientists tried to draw the analogy from the 205 gravitational field to the electric field, and eventually ran into a problem with magnetism: what could they ?give up? or ?tweak? about the scalar potential and still maintain its more important underlying structure (as a thing you differentiate to find the force)? ? the answer was to recast the scalar field as a vector field. Much of science consists of trying to extend a known law into a new area where it was not meant to be applied ? drawing analogies between pieces and ?tweaking? a few things. These tweaks ? that the electric field is like the gravitational field but different, or that in relativistic scenarios we must abandon simultaneity ? are the differ?nce introduced by Saussure and expanded upon by Barthes. They argue that in drawing an analogy between the two fields, the relevance is not in the ways in which the two are similar ? that overarching schema in which both are understood ? but the places where they are different. This idea has been termed the ?negative analogy? in the philosophy of science. Negative analogies as a caveat The negative analogy ? the pieces of the base that do not transfer to the target ? was first introduced by Hesse in 1966, but has not been widely recognized since. One reference can be found in ?The Metaphorical Transfer of Models? by P.B. Sloep (1997). In this article, Darwin?s natural selection is seen as an analogy to the selective breeding of gardeners, and the negative analogies are as crucial as the positive analogies: ?natural selection and artificial selection differ too. It is not for nothing that we said in the above ?it looks as if someone selected them.? While the proto-fantails were hand-picked by their breeders, in natural populations selection results from natural processes such as the struggle for existence. Here we have a difference or a negative analogy, as Hesse would call it: a human selecting agent versus natural processes. Negative analogies are as essential an ingredient of metaphorical transfer as positive analogies. A metaphor without them would cease to be a metaphor ? i.e. an explicitly non-literal referring term ? it would be the ?real thing? ? i.e. a literal referring term ? and we would end up with an identity 206 relation rather than one of analogy. At the same time, negative analogies embody the limitations of a metaphor? if negative analogies are not recognized for what they are, mistaken inferences loom large. It is true that negative analogies are a crucial element of science ? but not solely because ?if not recognized for what they are, mistaken inferences loom large.? I don?t want to place a caveat against negative analogies ? there is the danger in reading this passage and believing negative analogies to be no more than pitfalls, limitations and places for error. This interpretation of negative analogies is widespread (i.e., Gentner and Gentner, 1983; Clement, 1987; and Lulis, Evens and Michael, 2004). David Brookes (2003, 2004) has argued that scientists are inconsistent with their approaches to problems: speaking of quantum mechanics in the Bohmian sense one moment and then the Schrodinger model the next. We talk about heat as though it is a fluid, but treat it mathematically as a process. This is cited as a concern, but I believe that many and conflicting representations of phenomena may be a strength if appreciated and understood for what they are. Meaning arises in these negative analogies ? the places where the representations are not accurate (can lead to incorrect predictions) and where they conflict ? and this may be a strength of analogies. Meaning comes not only from the patterns and similarities between things but also the differences. It is in the tweaks ? the fact that the magnetic field is a vector, that heat seems like a fluid and isn?t, that we think of quantum mechanics in a Bohmian sense but also don?t ? that we find the science. Directions for future research regarding analogies and mind The changing schema 207 A direction for future research is to investigate what happens to the schemas through the use of analogy? How does the analogy change the understanding not only of the target, but also of the schema for which the base is a representation? For instances in which the schema is ?tweaked? in constructing analogies, how do we determine when it is a ?variation on a theme? and when it is a new theme altogether? Is this a continuum or is there a clean delineation between including the target in an established and stable schema and changing that schema slightly to accommodate the target? Conceptual blending A possible extension of these questions ? concerning how the negative analogies between the target and the base affect our understanding of the schema that applies ? relates to work on conceptual blending. Fauconnier and Turner (1994) note the following regarding conceptual blending (also known as conceptual integration): ? Mental spaces are small conceptual packets constructed as we think and talk, for purposes of local understanding and action. They are interconnected, and can be modified as thought and discourse unfold. ? In blending, structure from two input spaces is projected to a third space (the ?blend?). ? The blend inherits partial structure from the input spaces, and has emergent structure of its own. These ideas are related to and could possibly provide a partial answer to the questions raised above regarding how our schemas change to accommodate new phenomena. Constructed bases (as opposed to recalled ones) may arise from the piecing together of schemas that are not typically associated with one another. The implications of technology on science Another interesting question is to explore the connection between technology and theory. One interesting implication from Otis? research is that not only does our science 208 create new technology, but technology creates new science: not only because of the technological affordances, but the introduction of new schemas and new language. Scientists had no accurate way of envisioning the nervous system prior to the invention of the telegraph ? they borrowed language from hydraulics but it was of limited use. There was no way of understanding the olfactory system prior to the scanning tunneling microscope ? scientists spoke in terms of enzymes because that was the paradigm in other biological processes. Is this a rare phenomenon, or can most of our scientific theories and conceptual revolutions be, at least in part, attributed to changes in schemas that were brought about by new technologies? Science in the absence of analogy Related to this question are questions concerning systems for which there are no ?good? analogies. In particular, I am interested in the way that quantum mechanics is taught and the way in which it is conceptualized. There are few, if any, systems that are analogous to quantum mechanics: most seemingly analogous systems incorporate a ?hidden variables? component. What are the analogies that people use to understand quantum mechanics? What schemas do people tap into to understand and come to grips with this strange phenomenon? Above I suggested that quantum mechanics is perhaps not an analogy to physical phenomena but to mathematical ones. Although I later began to conceptualize probability amplitudes by comparing them to electromagnetic waves, it was initially an understanding of linear algebra that first informed and explained quantum mechanics. (My undergraduate professor for mathematical methods for physicists claimed that all of physics is linear algebra.) Of course, analogies from physical to mathematical systems beg the question as to whether or not mathematics is understood 209 via analogies to the physical world. Lakoff and Nunez, in the book Where Mathematics Comes From, argue that math, far from being an abstract and objective field, is intimately tied to analogies to the physical world: When you think about it, it seems obvious: The only mathematical ideas that human beings can have are ideas that the human brain allows. We know a lot about what human ideas are like from research in Cognitive Science. Most ideas are unconscious, and that is no less true of mathematical ideas. Abstract ideas, for the most part, arise via conceptual metaphor-a mechanism for projecting embodied (that is, sensory-motor) reasoning to abstract reasoning. This book argues that conceptual metaphor plays a central, defining role in mathematical ideas within the cognitive unconscious ? from arithmetic and algebra to sets and logic to infinity in all of its forms. (Lakoff and Nunez, 2001 preface) Embodied cognition and analogies in science In the above passage is a final question for generated analogies in science ? that of embodied cognition. The idea of embodied cognition is that ?human ideas are, to a large extent, grounded in sensory-motor experience. Abstract human ideas make use of precisely formulatable cognitive mechanisms such as conceptual metaphors that import modes of reasoning from sensory-motor experience.? (Lakoff and Nunez, 2001, xxi). That is, when you ask someone what a triangle is, the definition they immediately turn to is not mathematical formalism, but a process by which you draw that triangle ? often involving gestures. For abstract concepts like ?what is truth?? Barsalou and Wiemer-Hastings (2004) have shown that definitions often involve scenarios: ?It?s when you??. The relationship between analogies, categories, gesture and embodied cognition is interesting. The schemas that I have argued as fundamental are abstractions from concrete, embodied experience and analogies between concrete experiences, I have argued, are mediated by 210 this abstract schema. Perhaps at some deeper level, these schemas are represented as sensory-motor patterns, which are in turn associated with objects existing in the world, and the choice of base for our analogies may be related to this sensory-motor experience. This relationship has not been explored in this thesis but is a logical extension of this work. Analogies as a tool for exploring categorization Having established that analogies are assertions of categorization, this research can inform many of the open questions in categorization. Current questions involve the structure of categories and distinctions between taxonomic categories and other forms of categories. The vast majority of investigations of the mind?s organization start with a prompt for the participants of the study, such as asking for a list of trees, ?things to take from a house during a fire,? or even to guess at a professor?s judgment of the typicality of a certain type of bird. Such studies miss the everyday acts of categorization that happen without awareness or effort. Students in a class discussing why this sky is blue came up with many different analogies: the sky is like a bubble, a prism, or a neon sign. But when these students were informed by the instructor that their analogies all were ways of getting color from a colorless thing, they expressed surprise. And had they been given the prompt, ?what are ways to get color from colorless things,? it is not clear that the analogies ? or members of this category ? would have been identical to the analogies they constructed without such a prompt. This suggests an alternative and less ?invasive? or contrived manner of arriving at the organization of concepts by studying spontaneously- generated analogies. Network theory and analogy 211 A final direction for this research is to use analogies as a means of understanding the cognitive map as a conceptual network. Lexical maps have been constructed (Fellbaum, 2003 and others), that relate our semantic terms in a network ? thesaurus-like or internet-like in its construction. In these, words are nodes and linked to one another, and the activation of a node activates those that are linked to it. A similar construction has been considered for the linking and activtion of concepts (Collins and Loftus, 1975) ? but this would beg the question of what is a node? As Hofstadter notes (2001) a concept can be quite large and particular, as in ?a strange shape that the electrical charge may take that cannot be then be solved from first principles.? And yet our large concepts seem to be pieced together from smaller schemas. How are these concepts and schemas organized in the mind? What size pieces are fundamental ? or is that question even meaningful? Below I turn to questions for the implications of this research on instruction. Directions for future research on the implications for instruction While I make claims about what analogies assert and the cognitive mechanisms involved, I have not come to any conclusions about how this happens. How does Miranda make this incredible leap from seeing a cup of water to thinking of a cat in a basket ? why were these schemas activated for her? Of course the experience with the schemas involved was necessary, just as Luca Turin had to know about scanning electron microscopes before he could draw an analogy between this and scent, but what habits of mind and what structure of education can encourage this kind of creative re- categorization of concepts? Questions regarding student epistemology 212 As a first pass at a partial answer to this question, I would like to suggest that students must know that they should generate analogies as part of what it means to do science. That is, it requires a change of students? epistemological stance towards science. This is an argument that was discussed in the chapter regarding implications for instruction. But it leaves open the question as to how to change student epistemologies. I have found ? anecdotally ? that telling students to use analogies often results in superficial analogies: temperature equilibrating is analogized to a chameleon changing color, or an electrical circuit is imagined to be like a cow?s digestive tract (both analogies have occurred in Maryland physics classrooms). These students, when told to draw an analogy, are not choosing a story that makes sense to them could apply here. I don?t quite know what they?re doing with the analogies they construct ? and they don?t quite know why I am asking them to construct. In trying to understand these moments, I?ve wondered if these strange analogies can be understood in the context of a teaching philosophy from The Inner Game of Tennis (Gallwey, 1997). This sports psychology book argues that too explicit of instruction can (in the context of tennis) lead to unnatural and unfavorable results; telling someone where the ball should hit the racket, say, decontextualizes what should be one piece of an integrated whole. So perhaps an explicit focus on analogies prevents the natural evolution of an analogy ? as response to an unexpected result and stemming from activated schemas. This is just speculation at this point. But it suggests a possible starting point for how we can design curriculum and learning spaces in a way that encourages analogy generation. The design of learning environments 213 An additional, related question is whether the use of analogy (or lack thereof) a question of expectations, epistemology, or is it a domain-general ability? That is, in designing our learning environments to encourage analogy, should we be addressing students? ideas about what kind of knowledge they should bring to bear? Should we try to encourage the activation of multiple, contradictory schemas? Or is it a general facility with or predisposition towards analogies ? does a facility with analogies in, say, literature, translate to an increased use of analogy in science? Concluding thoughts Before my work on analogies, I was involved in curriculum development surrounding wave phenomena. In watching students interact with this and similar curricula I was dismayed that, though they eventually understood the concepts that the curriculum was addressing, the students never approached new topics in a creative, scientific, sophisticated way. They were better engineers in the end ? they could apply algorithms that the curriculum had carefully developed, but they weren?t better scientists. It seemed they were at a loss when learning new topics and constructing novel ideas. A student came to class one day wearing a t-shirt from a punk rock band. It read: You can lead a man to reason, but you can?t make him think. I wanted my work to address this. To begin to think of the classroom as more than a place to lead our students to reason, but as a place where deep scientific thinking occurs. I think this thesis is a start. It highlights one significant component of scientific thinking ? analogy. I claim that analogy is the ability to consider alternative models, deliberately overriding cognitive knee-jerk reactions to phenomena by tapping into alternative models and representing the categories that these models construct. 214 In Drawing on the Right Side of the Brain (Edwards, 1989), readers are instructed to turn a Picasso sketch upside down and then try to reproduce the upside-down drawing. Results are phenomenal ? even people who have trouble drawing stick figures are often create remarkably accurate reproductions. We cannot help but see a nose when a right- side-up nose is drawn before us, but by turning it over we can begin to see the lines and curves as lines and curves and override our assumptions about how noses are shaped or where eyes go. Analogies allow us to do a similar thing ? they demand that we turn the pictures upside down and dislodge the cognitive models that we were applying. Analogies allow us to stop seeing the nose as a nose ? we stop seeing the cup as a cup and instead pay attention to the way in which it as a basket, how metal is a set of stepping-stones and quantum mechanics problems are like Bugs Bunny?s ears. 215 Appendix A Transcript 1 This transcript is from an undergraduate course in physics, Physics 115: Inquiry into Physical Science. The students have been investigating electrical phenomena using Styrofoam (an insulator that charges easily when rubbed with wool) and a metal pie plate (a conductor). They began their study of charges using transparent ?scotch? tape: when two pieces of tape are put one on top of the other and peeled from a table top, they each get an excess of different types of electrical charge (positive and negative) which the students have termed ?top? and ?bottom.? Prior to the discussion below, the students have been asked why Styrofoam and metal have such different electrical properties and have worked in small groups to address this question. They are now presenting their ideas to the rest of the class: Hana: I kind of see the charge in metal as like, fish in a fish1 bowl? Like they never really stop moving, they?re2 always kind of floating around wherever they kind of feel3 like going and that?s just how I see it in my head, like4 them always moving around. And I don?t know what5 hap- I don?t know how to describe it really I don?t really6 know what happens once another charge is brought closer7 then.8 Instructor: Does this make sense to you then?9 Hana: Yeah.10 Instructor: So this is ? so this is like two kinds of fish. [Hana: Yeah.]1 And in metal they can move around. They?re kind of12 stuck inside the bowl, but within the bowl they can move13 around.14 Hana: But I also think that they can leave the bowl at some15 point because?16 Instructor: Well we get shocked right? I mean that?s?okay. I?m a17 charge I?m in the pie plate, what am I doin?? [Hana:18 Movin?.] Movin? I?m movin?.19 Kelli: That same idea I was thinking except more like ping pong20 balls that bounce all around and that?s why if there?s top21 216 and bottom charges they?re moving around a lot and2 they?re kind of attracting and repelling and attracting and23 repelling each other the tops and bottoms that go all over24 the place?but once the extra bottom charge is added it?s25 almost trying to like reneutralize itself and the tops are26 attracting to the extra bottoms. And then they?re trying to27 kick out the other extra bottoms so they can get back into28 their whole little [Student: Balance.] balance. Bouncing29 around.30 Instructor: So this- I think what you?re offering is an explanation of31 why I get a shock. Is that?am I wrong?32 Kelli: No, you?re not.3 Instructor: So you?re, you?re thinking that if there?s extra bottom34 charges in there it?s like they want to get out because it?s35 unbalanced. And it has to do with them just kind of all36 bouncing around like ping-pong balls if you?ve watched37 the lottery drawing. Alright. Okay. Terianna?38 Terianna: So- are you saying that they?so she?s saying?are you39 saying that there?s a little [inaudible] that charge moves40 throughout the pie plate?41 Kelli: I think I think so.42 Instructor: Okay?so are you agreeing with that picture that I drew43 down there?okay so it really is going with always4 moving.45 Christie: We were thinking that?like they were saying that in46 metal it?s always moving, so if it?s always moving it has47 more room to move and that would mean to say that the48 molecules are less tightly packed together or less dense49 and we were thinking of Styrofoam as more dense than?50 I?m just trying to figure out first if that?s right and how it51 relates.52 Lea: I don?t agree with you saying that the Styrofoam is more53 dense because, so that?s why the charges get caught up in54 it because like?[inaudible] pan is more dense so they?re5 able to slide across it like they can ice skate across the56 [inaudible] here. So that?s why they move around more57 ?cause it?s more dense so they can slide across it more58 and the Styrofoam is less dense and so they get stuck in59 it. Like so they can?t move as much.60 Instructor: Lea I want to add?I think you?re sort of what I when I61 hear you talk I?m thinking of like, pouring water into a62 sponge versus pouring water onto a hard surface. [Lea:63 Yeah.] Like this sponge is actually less dense and there?s64 room for it to absorb the water and the you know if you65 pour it onto something hard there?s no room for it to6 217 absorb. But Christie?I mean this is an interesting thing67 you guys are both thinking that density is important but68 one of you is thinking that more density means one thing69 and one of you is thinking more density means the other70 thing. Is that is that?am I right? [Christie: Yeah.]71 Lea:Yeah, I have a question about the sponge- like the charge72 instead of being able to move freely past it and they get73 kind of stuck in it like water and the pan is like the74 countertop and you pour water on it it?s going to slide all75 around and stuff but the charges can move more freely on76 the pan there?s probably? I think that maybe this has7 more charge in it because there?s more places for the78 charge to leave than the pan does, but there?s more79 potential charge in this than the pie pan. [Unknown: Like80 it can hold more charge.] Yeah it can hold more charge81 but they can?t move around as freely.82 Student:So you?re saying the charge is like [inaudible] out on the83 metal? Like on the outside?84 Lea: Yes.85 Student:It?s like made up of it?like, they?re electrons.86 Lea: Yeah?like I don?t know but it?s like definitely a lot87 smoother. They?re, they?re denser they can move around8 more freely like.89 Instructor:Hana?90 Hana: As, as far as like air is concerned?air moves from high91 pressure areas to low pressure areas and so like I don?t92 know I don?t know if that?s like a completely separate93 idea?94 Instructor: But you?re offering this as a kind of ?maybe this explains95 why there?s charge pressure?there?s high charge96 pressure and low charge pressure.?97 Hana: Kind of but I know that I know that high?like when98 you?re in the shower and the shower doors close and it9 gets all steamy as soon you open the door you feel like10 the cold air feels like it?s rushing in? Because inside the101 shower it?s low pressure and then once the door opens all102 that high pressure kind of like rolls right into the into the103 low pressure area.104 Instructor: I just want to- I know- there are people here- I just want105 to clarify Lea and Hana your question your question was106 is charge moving on the surface as opposed to moving107 inside and so this would be like are the fish swimming in108 the middle of the fishbowl or are they somehow sort of109 stuck on the edge of the fishbowl. Is that sort of what10 you?re ? [yeah I disagree with her idea] okay.11 218 Lea: I really don?t know I was just trying to?12 Lydia: I was going to say I think the pie plate is more dense but I13 do think that it?s inside not outside because if there?s14 more space to travel then the molecules can?t get from15 one space to another easily but it?s all [inaudible].16 Instructor: Oh so it?s like stepping stones [Lydia: Kind of.] like in17 the Styrofoam it?s really far to the next stepping stone so18 it?s like can?t get there I?m stuck here. [Lydia: Right] but19 in the metal the stones are really close together so I can120 kind of walk across. [Lydia: Yeah.]121 219 Appendix B Transcript 2 The following analogy is from a 5 th grade classroom in a rural Maryland public school. In this transcript, the students have been visited by the science resource teacher and posed the following question (NASA, 1999): a cup full of water is inverted on a cookie tray and the tray is rapidly pulled out from underneath the cup (see Fig. 2). What happens to the cup-water system? The students will later observe that the water does not Fig. 2: The Experiment: A tray pulled out from under a cup leave the cup as it falls to the ground?the cup falls at the same rate as the water and the water will only spill out once it reaches the ground. Teacher: So you?re predicting as I slide the cup off it?s also going1 to go all over the tray, too.2 Gabrielle: Like, it?ll spread and then it will fall.3 Teacher: It?s- the water is going to spread and then it?s going to4 fall down. Okay now I might come back to some of these5 ideas that you?ve had but let?s see what some ? I see a lot6 of other hands up. Um, Miranda?7 Miranda: I predict that when it falls off it?s going to stay in the cup8 until it gets down to the floor and then it?ll splash.9 Teacher: So you have a prediction that when I slide it off of the10 tray the water is going to stay in the cup. Now that?s very1 different from what they?re saying.12 Miranda: ?Cause at home when I have like something in a basket13 and when I go like that real quick it stays in. So when ?14 and when I pull it down like this like upside down on the15 220 way down it stays in until it gets to the bottom and then it16 comes out.17 Teacher: So you?re using now this example of something that18 you?ve done at home where you have an object in a19 bucket- or a basket- you said and what do you do? You?20 Miranda: I go like this and then I pull it down and it stays at the top21 until I stop and then it comes out.2 Teacher: So you swing this ? what?s in the basket? What object is23 in the basket?24 Miranda: Sometimes I put like like a little toy cat that I?m playing25 ?roller-coaster? with and put it in there and I pull it down26 [Teacher: Is that right?] and it stays in the back until I27 stop and then it comes out.28 Teacher: So you swing this basket like this?do you, do you do it29 quickly or slowly? Or.30 Miranda: I do it quickly like that.31 Teacher: You do it like that and then pull it down [Miranda: Mm32 hmm.] and the cat stays in the basket [Miranda: Until I3 stop.] even when you have it upside down like this and34 pulling it down and when you stop35 Miranda: It comes out.36 Teacher: The cat comes out. Okay now has anybody else- want,37 can relate to this also? Looks like a lot of you can. Let?s38 hear some of your ideas. Let me come over to ? thank39 you Alyssa.40 Alyssa: Um. Um what she?s also talking about it?s the air- it?s41 like pushing the cat up against the the bottom of the42 basket which is holding it back from going out.43 Teacher: Okay, so now you?re- and this is where I was going to go,4 too, after what you said is, um, explain how the cat would45 stay in there and you?re thinking is, Alyssa, is that the46 air?47 Alyssa: ?is pushing the cat towards the bottom.48 Teacher: Okay, so so the air is pushing the cat towards the bottom49 of the basket keeping it inside the basket. When?now50 when I?m thinking of that, and maybe some of the others51 can help me with this, but I can picture the air when you52 pull it down being forced up against the cat?is that what53 you?re talking about? Miranda?54 Miranda: And it?ll be the same thing with the water the air will5 push the water up until it falls down and then it will go56 everywhere. Because when it comes down the air is57 pushing upwards and [it keeps/I keep?] the water in there-58 because I?ve also done that in the bathtub when you?ve59 got your cup, I?ll like I?ll fill it with water put my hand60 221 and drop it the water stays in until it hits the bathtub and61 then it goes everywhere.62 Teacher: So your thinking is then this air is keeping the water63 inside the cup. Alyssa your thinking is that the air keeps64 the cat inside that basket that Miranda was describing.65 You?re shaking your head ?no? Gabrielle?6 Gabrielle: Yeah because like when you put like a toy cat in a basket,67 that?s only that one small thing but you now have a cup68 full of water, so how would the air keep it up if the cup is69 already full?70 Teacher: I?m I?m not sure I follow what you just described, you71 said the cat is just a small [Gabrielle: Toy.] toy so?72 Gabrielle: So and it?s only one thing.73 Teacher: Okay wait a minute?so the cat?s only one thing but the74 water is?75 Gabrielle: So you you?re going to have the cup full so how would76 the air like keep it up if the cup is full?7 Teacher: Oh- so her did you hear what she just said Miranda?78 [Miranda: Mm hmm.] She?s saying that if I fill the cup-79 if I fill this cup- you, you?re saying if I fill the cup to the80 very top there?s no room for the air to keep the water in81 there. Okay well, I I have a question for you then82 Gabrielle?what?s your prediction if I fill this cup all the83 way to the top, turn it over, slide the cup off what will the84 water do? I filled it all the way to the top, turned it over.85 Gabrielle: How far do you now have the cup up?86 Teacher: How far in the air?87 Gabrielle: No to the edge.8 Teacher: Oh to the edge? I ? I was probably, I don?t know, as89 close to the edge as I can get it.90 Gabrielle: Well, I think it?s91 Teacher: And then I?ll do this. Or?92 Gabrielle: Oh my prediction is that um, what Alexandra said that the93 cup slides off then it?ll just go down?94 Teacher: Okay so you?re still with your original prediction where95 you think the water is going to go everywhere.96 Gabrielle: Yeah but it?s?I think it, what it?s going to do, is the97 cup?ll fall off and some of the water will splash into the98 bucket. I don?t think it?s going to go?9 Teacher: I?m sorry say that one more time it?s going to do what?10 It?s going to?101 Gabrielle: I think when the cup slides off that the water will go102 down to the bucket and make a splash.103 Teacher: So it?s not going to stay in the cup like Miranda?s104 predicting.105 222 Gabrielle: Right.106 Teacher: Okay what about if I only fill the cup up halfway? Now107 we?ve got room for this idea we?ve got room for the air.108 What do you predict will happen? And I slide it off of109 there. Maybe I?ll just push it off of there like that.10 [Teacher pushes empty cup off and it tumbles in the air11 on its way down.]12 Gabrielle: Well, see, the cup like turned a little bit, it like went side13 a little bit so um.14 Teacher: Well what do you predict the water will do if I only fill it15 half way? Is it going to do the same thing as if I fill it all16 the way?17 Gabrielle: Um? yes it?s going to do the same thing.18 Teacher: It?s going to do the same thing. [Gabrielle: Yes.] So you19 don?t think air has anything to do with it then? Keeping120 the water in the cup?121 Gabrielle: No because like when you?re turning the basket then you12 kind of keep it straight when you?re holding the handle123 like that. When you drop the cup the cup can just zoom124 all directions too.125 Teacher: Oh I see what you?re saying?when you?re holding the126 handle on a on a basket or a bucket you?re kind of127 keeping?128 Gabrielle: You?re keeping it straight.129 Teacher: But your thinking is when it falls like this it could130 tumble?it?s going to move?there could be some131 movement in the cup.132 Gabrielle: It?ll turn sideways.13 Teacher: It could turn sideways like that. And that would make a134 difference. Okay let?s get ? a lot of you have been very135 patient. Cody?136 Cody: Um because when I was um having bucket full of water137 and I swing it around and then when I throw it the bucket138 of water still stays in there- the water, and139 Teacher: You?re going around throwing buckets of water?140 Cody: Yeah-they?re made out of plastic.141 Teacher: When you when you swing that bucket of water around?142 Cody: Yeah and then when I throw it the bucket of water still143 stays until it hits something.14 Teacher: So the water stays inside the bucket even when you when145 you?ve let it go the water stays inside of there. Well what146 do you predict will happen when I do this with the cup of147 water?148 Cody: It will turn before it hits.149 Teacher: What will turn, the cup?150 223 Cody: It- it would, the water would go out a little bit and then it151 would splash.152 Teacher: When I do this, what will the water do?153 Cody: Um the water ? if you pushed it hard enough the water154 would go out flat a little bit and then fall.15 Teacher: So if I push it hard enough?well that might not be a156 good example. But if I push it hard enough you?re saying157 that water will stay there for a moment- it will stay flat is158 what you said- and then what would happen?159 Cody: Then it will fall down.160 Teacher: And then the water?s going to fall down. Out of the cup?161 The water will fall out of the cup? Or?162 Cody: The water would splash out before it- after it gets out of163 the cup and then fall down.164 Teacher: So it?s going to it?s going to go like this, water?s going to165 stay flat for a split second?16 Cody: And then the cup and the water will fall down.167 Teacher: Will the water stay in the cup as it?s falling? The water?s168 going to fall out of the cup. But you just said that when169 you swing the bucket, though, that the water stays in170 there.171 Cody: But when you push on the flat then um? It?ll turn172 around?173 Teacher: So we?re still thinking about this pushing it off of here,174 though?that175 Cody:[Inaudible.]176 Teacher: So it forces the cup to to uh turn. Isaac?17 Isaac: Um I pre- I don?t- um I agree with Miranda but I don?t178 think air has anything to do with it. Because um179 yesterday at Trick-at-Treat I had like a bunch of candy180 and I swung it around that?s like when I was bored and181 stuff?182 Teacher:In your bag?183 Isaac: Yeah. And none of the candy came out. I like kept on184 swinging it and also when me and Johnny play monopoly185 there?s like this little hat that we play with when we roll186 the dice [Teacher: Mmm hmm.] and like we always put187 the dice in and flip it back to each other with the dice in it18 and we always catch it and it stays and the dice stay in.189 Teacher: And you?re in agreement with Miranda that the water will190 stay in the cup however you don?t think air has anything191 to do with it.192 Isaac: No.193 224 Teacher: Have you given any thoughts as to why the water will194 stay in the cup or what what uh what will cause the water195 to stay in there?196 Isaac: I just predict that cause of experiments?197 [a few minutes of conversation regarding what happens198 before the cup falls]19 Teacher:?Alexandra?20 Alexandra: Um when Miranda said how when she dropped the cat in201 a um basket- I?ve done that with um my Easter candy but202 with more candy in it and when I turned it over when I203 got up here and it dropped it all went everywhere.204 Teacher: But when you were swinging it, it didn?t fall out until you205 got up here and then stopped and then it all fell out.206 [Alexandra nods.]207 Teacher: Isaac?208 Isaac: I don?t really agree with Dillon because the only reason209 it?ll fall out is, um, if the board is crooked and the cup is210 straight and also if the cup has a crack in it.21 Teacher: The cup is pretty good- I mean it doesn?t have any cracks212 in it, and although the cookie tray it looks a little? pretty213 straight. It?s hard for you to tell I know. Um. Let me214 just summarize, really, for my own benefit and perhaps215 for yours as well. And then we?ll come to you Gabrielle.216 Teacher: We have a couple of different ideas. At least three I217 think. We have Dillon and his group who are thinking218 that ? or I?m sorry predicting ? that when I turn the cup219 over the water is going to go everywhere. We have20 another group, I think it might be I would call the21 Amanda group who is predicting that water?s going to22 stay that it will stay in the cup even when I turn it over23 and the water will stay in the cup when I push it off of the24 tray. Ok? And then we have some of you- Alexandra25 who had originally predicted and Gabrielle that water is26 going to fall out of the cup when I push it off of the tray.27 Are there any other ideas, other than those three?28 Ethan: Are we going to be able to try it out.29 Teacher: We are going to be able to try it out.230 Student 1: Today?231 Teacher: Today.232 Student 2: We always do it fifteen minutes before we?re done.23 Teacher: Well now I want to hear your talking and your thinking234 about this now. Gabrielle, you had something to share go235 ahead.236 Gabrielle: I was going to say that I think the water will fall out once237 it leaves the board.238 225 Teacher: Soon as I do this the water?s going to.239 Gabrielle: Yeah because see when you put the board240 Teacher: The Cookie Tray?241 Gabrielle: Yeah.242 Teacher: Please use the correct scientific terms, ok, this is a243 ?Cookie Tray.? I?m just kidding.24 Gabrielle: When you put the cup on the tray and then when you go245 to slide it off some, some of it like that- not all of it246 comes off at once. Some of it comes off a little bit so I247 think when, when a little bit is off the water will just fall248 down because there?s a crack.249 Teacher: Oh. Let, let me repeat what I heard you say and then I?ll250 get to you Alexandra. It gets to this point some of the251 water is going to come out.252 Gabrielle: Yeah because, um, that part has a gap in it so I think the253 water?s going to fall out.254 Teacher: Do you see what she?s talking about you have this little25 bit?256 226 Appendix C Transcript 3 The first transcript below is from a research group meeting of the Physics Education Research Group. Paul, a graduate student, is interested in authentic classroom activities and is discussing his definition of authentic. Key to this definition is that authenticity is a property not only of the activity but also but also in the way that the students relate to that activity and the coherence of this to the scientific community of practice (that is, do the students know what they?re doing? Would scientists agree?). This is at odds with definitions of ?authentic? activities that situate authenticity as a property of the curriculum itself. The transcript begins with David summarizing the concerns with respect to prior definitions of authentic. David: It?s not a responsive definition of authentic. Authentic is1 defined pre-experience. And so what your [Paul?s] sense2 is what?s going to be authentic is about watching the3 student and and what is authentic for this group?may be4 different from what?s authentic science for this group.5 And you don?t like defining authenticity in a way that6 isn?t responsive. So the content isn?t responsive but also7 the sense of what is authentic isn?t responsive.8 Rachel: So ontologically authenticity is like fun. Which would9 be?10 David: Oh that?s great.1 Andy: Oh that is beautiful!12 [Laughter.]13 Rachel: ?because you can?14 David: There?s an analogy for you Leslie. [Leslie: Yeah.] Are15 you taping this? [Leslie: It?s being taped.] Alright.16 Andy: ? it emerges from an activity but it?s really ultimately17 lives inside?18 Rachel: Right and I mean you could say?I mean you couldn?t19 look at a thing on paper and declare that it was fun until20 you could see people do it and see them have fun.21 David: And it may be fun for some people and not fun for other2 people.23 227 Andy: You could ? an experienced teacher could make guesses24 about what?s more likely to result in fun blah blah blah.25 Rachel: Sure, sure. But really ultimately you don?t know until26 after [inaudible].27 David: Or anyone?what what my kids think of as fun might not28 be the same as what Rachel thinks of as fun [trails off].29 I?m sorry I?m just struck I?m I?m thinking of Leslie?s30 stuff for a moment?what?s cool is how powerful it is to31 connect that question?how powerful it is what you just32 did. That when you say it?s like ?fun? boy that brings in a3 lot of stuff to help me understand the kind of claim that34 that we?re batting around.35 [Undiscernable/is that right? Comments.]36 Paul: Ten minutes?we could break early?37 Leslie: Is there a community of fun practice?38 [Laughter.]39 Rachel: Or norms? [Laughter.]40 Leslie: Like with the community of practice the scientist is41 someone who?s outside deciding whether or not it was42 science but with fun there isn?t ? so it?s a negative43 analogy?but with a community... yeah there?s no4 community of practice.45 David: I don?t know what you mean? there?s no authentic46 community of practice?47 Leslie: You only have to ask a person who?s having fun if48 they?re having fun. But this (definition of authenticity)49 implies that you have to ask the scientists whether they?re50 doing science.51 David: Ahhh?right. Gotcha.52 Andy: Not only does it have to be meaningful it has to be53 meaningful in the right way?but? yeah I?m having fun54 but it?s ? you know?low-brow fun instead of highbrow5 fun. Guffaw guffaw! Gotcha.56 [Laughter.]57 David: So can we patch that? Is there, is there another58 Matty: [Indiscernible. Overlap?like.]59 Rachel: Good clean fun?60 [Laughter.]61 Matty: Like I?m wondering you know?what can be considered62 ?fun? by a group of people you know there?s like overlap63 like a culture who considers certain kinds of things fun64 and there?s like overlap between the adult (?)65 individuals?same with like if you consider that like the6 community of fun practice, like the community of67 science, I think individually everyone would consider...68 228 Leslie: I have a multiple analogy if that?s okay? I?m thinking it?s69 more like worship?like, you know if you?re worshipping70 but a religion is going to also decide if what you did was71 worship.72 Andy: Oooh.73 David: Right. Right that?s good.74 Andy: It?s gotta pass both tests. That is good. Good clean fun75 works, too. You decide if it?s fun, I decide if it?s good76 and clean!7 [Laughter.]78 Leslie: Or pornography?79 [Laughter.]80 David: Paul wants to stop. We?re done.81 229 Appendix D Transcript 4 The following transcript is from a third grade classroom in a suburban Maryland public school. In this classroom, the teacher has asked the students: if you are running with a beanbag and want it to fall on an X, should you release it before, when, or after you reach the X? This question is particularly interesting because all three answers are plausible and can be argued with analogies to past experiences. Camille: I think? I think that you?re gonna drop it before.1 Teacher: Why?2 Camille: Because it? you just keep on running and then? I don?t3 know.4 Teacher: Why would it not drop straight down?5 Camille: Um? I?m just thinking that maybe if you?re running it6 might just go back, back? I mean forward when?7 Teacher: Because I am running? And it will go forward with me8 because I?m running?9 Camille: Yeah.10 Teacher: How many people think it will be forward? it will go1 forward. I need to drop it like somewhere around here.12 Way before hand. Adam, that?s what you think? When13 you back up, can you help me please.14 Adam: Um, I think, because one of Isaac Newton?s rule of15 physics is a body in motions tend to stay? a body in16 motion tends to stay in motion until stopped, or17 something like that. And that, um? when you?re18 running and you let go, if you let go before, it will? it19 will instead of going straight down, it will go um? it20 will go in front because it?s not stopped yet. But when it21 hits the ground, because there is friction on the ground?2 there is more friction on the ground than in the air it will23 get stopped and land somewhere around there.24 Teacher: You had a really um? a really good idea that I want you25 to really kind of explain it to some people that may not26 understand your law of motion and may not understand27 the word friction. So I need you to try to restate your28 idea, and try to think about not even using that law as29 an? as an example, but trying to just explain it to30 someone using your experiences? see if you can use it31 230 that way. Explain to? like you?re explaining to a32 kindergartner. They?re not going to be able to understand3 that law.34 Adam: Like um?if?like if something?if you?re riding your35 bike, um?it?s in motion. And you?re going to keep36 going until you get stopped by like? um, a rock or37 something. And, and?or going uphill. And so if you?re38 on a bike, and you get?you can get stopped by39 something else, like a rock or something.40 Teacher: So if we?re thinking of your analogy to a bike, or your41 explanation with a bike, what?s stopping it, and this is?42 Adam: Um, no. Well, in the situation of dropping the beanbag.43 Like, um, it?s thing is the ground, and because the4 beanbag is running against the ground, um? it?s getting45 slower. Because like the beanbag is um? getting? I46 don?t know how to explain this.47 Teacher: Well, I?m gonna ask you a question, I want you to think48 about it for a second, and then I am going to come back49 to you. Okay? I want you to think about whether you50 think the beanbag?s in motion. Because you know I?m in51 motion: my body?s moving, but is the beanbag in motion?52 I want you to think about that question and I?m going to53 come to you in just a minute. Okay. Um? Connor?54 Connor: I would think the bean bag would?might fall behind5 where you want it to fall because when I put?when I56 played baseball?they always said don?t throw the bat57 because it might hit the catcher and not one of the um58 person because we?re using metal bats, and?so we drop59 it, you drop it and then you?. Well, when I drop it, it60 usually swings backwards; it wouldn?t be behind the plate61 instead of the front of the plate.62 Teacher: So you?re saying you have to drop it like somewhere over63 there, right? in order to get it to fall over there?64 Connor: Probably.65 Teacher: Cause of baseball.6 Connor: Yes.67 Teacher: And you saw that it usually fell behind.68 Connor: Yes.69 Teacher: Why do you think it fell behind?70 Connor: Well actually it didn?t mostly. It got on the side or in71 front because? well because you?re supposed to drop it72 because you don?t need a bat while you?re running the73 bases. Once you drop it, I?m just thinking also, what74 Adam is? well a bus? well if you were on a bus and75 you had uh, this little leaf that you found, and the window76 231 was open, and you drop it, it will go? it?ll be going7 backwards.78 Lauren: That?s because?79 Teacher: That?s okay, you can interrupt him if you want to talk80 about his idea.81 Connor: It might go backwards.82 Lauren: Because I think that?s cause? you?re talking about a leaf83 that?s falling? That?s because the? it?s sort of? the bus84 is going back, so it?s making like the air move. And the85 leaves are really, really light, so the reason they are going86 backward is because?. Um, well it?s going so fast? a87 bus is like going so fast that it?s probably making the air8 go that way. So that way the leaves are going that way.89 [Many talking in disagreement.]90 Connor: What if you did it with a rock? The same thing will91 probably happen with a rock. Because you are probably92 like a bus, that you make the air come? no one moves,93 don?t you notice that um, objects like in cars or94 something? when you?re going really fast on your bike95 that are? that um, you sometimes, [inaudible] and leaves96 your ankle on your back step and actually move.97 Val: We?re talking about a bean bag.98 Teacher: What do you think is the key to that? His question is, is9 about the beanbag. So, um, since he?s thinking that10 maybe the weight matters? what I am going to do is just101 pass this around, so you can touch it and think about that,102 um? if you think the weight matters, might help you to103 answer the question?104 Kamran: Well, I think that?105 Teacher: You can?t interrupt somebody. You can share ideas, but106 you can?t interrupt somebody as they?re sharing. Okay107 you have to make sure he?s finished. And when108 Connor?s finished he?ll let you know by calling on109 another person. Okay?10 Connor: ? but sometimes, yes I do believe that it might be about11 the weight also. So the heavier it is, probably it would12 land where you want it to. So say you had like a rock13 besides that beanbag, it would probably land where you14 wanted it to, because it would probably be heavier than15 the beanbag.16 [Interruption as another teacher asks an unrelated17 question]18 Teacher: Connor has this idea that the depend? it depends on how19 heavy the object is that we?re dropped. So I passed120 around the bean bag. And um? that might be a good121 232 idea for Kamran to talk about, so Kamran is going to talk12 about that now. The weight and whether or not that123 matters.124 Kamran: Yeah I think weight matters, because when Newton125 discovered gravity, gravity it?s, it?s has heavy enough to126 come straight down. If you?re moving and I?m not127 talking about beanbag, and I?m gonna put a pencil here128 and pretend that?s my mark. And then I ?m going to129 move, but then I?m gonna drop down it and see what130 happens. But? like?131 Teacher: I don?t want you test it. We?re talking about it first.132 We?re not going to test it, okay?13 Kamran: Yeah, okay. But, but, I think that it, it, it matters on134 weight. A bus? you?re on a bus and the bus is the135 motion. Now if you drop a feather, that feather is going136 to go back. Also the bus in motion is producing like a137 kind of wind.138 Teacher: Yeah, mmhmm.139 Kamran: It?s giving air. Yeah. So the air is getting pushed into?140 it?s pushing the air back. Um? this is a drawing, this is141 the air, this is the bus. The bus is going? the air is going142 back. And if one of the windows, a feather comes the air143 is pushing it away.14 Teacher: Mmhmm. Okay, okay.145 Kamran: But, if you? cause you know a feather is? it, it, it goes146 with the air just simply its a light. That?s why? same147 with a leaf. A leaf is very light. And if you? a leaf falls148 [Inaudible.] goes to air. It doesn?t go, ?leaf? boom.? It149 doesn?t go like that.150 Teacher: Okay, so?151 Kamran: But a rock?152 Teacher: Yeah?153 Kamran: A rock is different, a rock has? it?s also like, it?s solid,154 but it?s not that a leaf isn?t solid, or a feather isn?t solid.15 A feather? but you have to? it?s very small, and it?s156 very like thin, so you kind of say like solid. But anything157 hollow, like if you have a paper box, that people would158 watch [Inaudible.]?159 Teacher: Now we have a beanbag here. So since we have a160 beanbag, and you know that it?s not in a bus, we?re just161 driving? I mean we?re just running. What do you think162 is gonna happen?163 Kamran: This?164 Teacher: Cause you have that weight in your hand so you have a165 good idea.16 233 Kamran: Um?. now this is hard, because somehow you can see167 it?s heavy, and somehow you can say it?s very light.168 Kamran: It?s hard, that?s hard to say.169 Teacher: So Cameron. So if you had to? get to share your idea170 right now what would it be. Where do you think you171 think you need to stand to get it to hit right there.172 Kamran: I think you have to put it right there. Probably? we?ll it173 depends on what? here, you?re dropping it? you?re174 dropping it here, here?175 Teacher: Right by my side? just drop it? I?m just dropping, not176 throwing. Just drop it.17 Kamran: Yeah I think you have to be on, in order to? you have to178 be on this directly, and the middle of your shoe has to be179 on the line in order to make it drop?180 Teacher: Okay and you? and you?181 Kamran: Into it also, also it?s the most of minute [Inaudible.], if182 you?re going to see your shoe going on this [inaudible].183 Teacher: It will go to the left.184 Kamran: Yes.185 Teacher: Um? Now you?re reason for having it hit right there,186 does that have something to do with the weight?187 Kamran: Yeah, because the weight pulls it right down. If a tree?18 it?s heavy, and it?s heavier than all the leaves it has, so189 the leaves will make it fly.190 [Laughter.]191 Kamran: ? flies here. And the tree, it will just go down.192 Teacher: Okay, can you share? can you call on somebody that?s193 going to agree or disagree with you now.194 Kamran: Um?Kathryn.195 Kathryn: Um I agree with what you?re saying and all [Inaudible.]...196 Teacher: I?m sorry, I can?t? I can?t go on cause I can?t hear you197 very well.198 Kathryn: Um, uh? when you told me the first time, I didn?t really19 get it, so I [Inaudible.]?.20 Teacher: That?s okay.201 Kathryn: Can redo it?202 Teacher: Um, don?t worry about that now.203 Kathryn: Okay. I think that if you want it to land? well if you?re204 riding on a bus and you drop the rock down, it?s heavier205 than the wind, so I think it?ll go straight down.206 Teacher: So you think that it needs to be heavier than the wind.207 Kathryn: Yes, cause it?s going to go straight down. A beanbag and208 the rug?if it?s heavy and um? I would say you would209 have to be in the middle of the line, because210 [inaudible]? if you?re running it?ll go all the way behind21 234 you. But if it?s heavy enough, it?ll just drown you have212 to be in the middle of the line.213 Teacher: Okay, I am going to ask you to stop right now.214 235 Appendix E Transcript 5 The following transcript follows two undergraduate physics majors working on a homework assignment on angular momentum in quantum mechanics. The students have had instruction on how to arrive at the quantum numbers S and L but are asked to find the square of the total angular momentum, J 2 , which is (S + L) 2 , or S 2 +2SL+L 2 . The students know how to find S 2 and L 2 but not 2SL. They have a solution set from another student that provides the answer but not the steps to arrive at that answer. Ben: That?s what we?re looking for in the first place. You1 don?t think that?s it?2 Anselm: Well J^2 is L^2 plus S^2 plus 2SL. And SL is3 presumably the thing that could take on separate values4 within the probabilities.5 Ben: It doesn?t talk about J^2 though does it. [unclear]6 formula [unclear]. Although we should be able to figure7 it out cause it said the rules are the same whether you use8 spin or angular momentum.9 Anselm: Yeah. That?s fine if you know the rule. But we don?t10 know what S times L really does. Cause SL doesn?t1 really have a quantum number. Is it the square root of S12 and the square root of little-L, and then you take that13 times that plus one?14 Ben: We should be able to figure this out from today?s lecture.15 Anselm: No you shouldn?t.16 Ben: He?s gonna explain in detail probably Wednesday how17 you actually get to J.18 Anselm: But see you?re doing the wrong thing. Cause you?re19 assuming that if you have the example, suppose there?s a20 charge here, what?s the electric field due to it? You can21 figure out, suppose you have Bugs Bunny, and he?s2 charged, what?s the electric field around his ears? All23 right. Because you have a simple example when they?re24 both the same, you?re not going to be able to figure out25 exactly what you?re supposed to do when the rules26 weren?t the same. Cause now it?s fixed.27 236 Ben: What other choice do we have?28 Anselm: So like there?s no like S, S+1, it?s more like the square29 root of little-L times the square root of little-S maybe? I30 don?t know.31 Ben: Well what other choice do we have?32 Anselm: Cry?3 Ben: How else - Yeah. Okay, let?s cry, I?ll go cry. Now let?s34 go on to B. ...I don?t see anything that [I think?s gonna35 help us]. And I feel like the book is just pathetic in this36 regard. It doesn?t give us any help at all. I don?t think it37 does, let me look back maybe there was something in it38 that helps. Combining spin and [angular momentum].39 Anselm: Does your thing have the answers for this problem or40 not?41 Ben: Yeah.42 Anselm: So are there multiple J-squareds then?43 Ben: Yes there are.4 Anselm: Are they the ones we found?45 Ben: No they?re not.46 Anselm: All right. What are they? Let?s work from the answer.47 Ben: Eight-ninths and one-ninth.48 Anselm: That?s the probabilities?49 Ben: Uh-huh.50 Anselm: Eight-ninths and one-ninth. All right. And what51 are?what are the values?52 Ben: Fifteen whatevers in the, whatever we came up with. The53 values are the same.54 Anselm: We didn?t come up with that.5 Ben: Yes we did.56 Anselm: Well yeah we did.57 Ben: These are the values.58 Anselm: Yeah we did come up with the values. Um, but it?s eight-59 ninths and one-ninth? And now you say60 Ben: If you want to believe that.61 Anselm: And now you say - You said at one point you had eight-62 ninths and one-ninth, where?d you get eight-ninths and63 one-ninth. What did you do.64 Ben: All right, look at this look at this. If you take all the65 positives and add them together, you get eight-ninths.6 Anselm: Oh, oh.67 Ben: You take the negative, you get one-ninth.68 Anselm: Yeah that?s69 Ben: But you?re mixing apples and oranges. It?s dumb!70 Anselm: Yeah that?s so messed up, yeah that?s not the answer. If I71 just ignore the fact that I?m in the three-halves one-half72 237 and I?m in the one-half one-half and I just add them all73 together,74 Ben: I once had a professor tell me that um, well if you got the75 right answer, you certainly know how to do the problem.76 I had to convince him no sir, you can jiggle these7 numbers any way you want. And come up with the right78 answer if you know the right answer in advance. Of79 course we?re not sure that this is the right answer.80 Anselm: It?s been pretty good. Except for h-bar [seize two]. All81 right so somehow we need to get eight-ninths and one-82 ninth?83 Ben: Yeah. Somehow.84 Anselm: [muttering - reading?] If we were somehow free to swap85 around some of these square root of two over threes, then86 we could make it.87 Ben: No they came from the table.8 Anselm: Yeah, but I?m saying if we were.89 Ben: [shakes head]90 Anselm: I know we?re not.91 Ben: Wishful thinking won?t help.92 Anselm: We would have to?yeah somehow it would only be the93 square root of two-thirds would have to multiply both of94 these.95 Ben: We can always [unclear] from class. You made me late96 for class this morning.97 Anselm: I! You were the one, excuse me,98 Ben: You insisted on going over problem 37 and9 Anselm: My last semester of college I?ve never been late to class10 before and it?s all your fault. Ruined my record, man.101 238 Appendix F Transcript 6 The transcript below is from a discussion that faculty members at the Governor?s School of North Carolina had in the lounge of the faculty dorm. One faculty member, Steve, asked what I was teaching in my class and mentioned that students wondered if humans would ?blow up? in space or not. The faculty began discussing this question and began to tease apart different factors by considering what would happen to a statue in space (this statue was Michelangelo?s David and references to David in the text are regarding that discussion). This discussion then turned to whether or not a human would freeze while in space or heat up from the sun. This lasted much of the afternoon and we agreed to continue on the following Sunday. They began the discussion the next Sunday by wondering how the Earth heats up and cools off, which turned to a question about seasons: are they due to the elliptical orbit or due to the tilt of the Earth? The transcript below starts with that question. (?Leslie? in this transcript is me?the author.) Leslie: Okay, so where are we now on the ellipse question? Tom: I think this whole, if the sun is not at the center of the1 ellipse but is one of the foci of the ellipse [which is true] I2 think this whole business thing3 ?: Is all about the atmosphere filtering4 Marc: Un-unless you?unless we could measure and discover5 that, one hemisphere?s average temperature is different6 than the others7 Joel: Well but the earth is much fatter in the middle, you know8 what I mean? So the part that?s that?s facing the sun, the9 closest part to the sun the on that?s getting the most direct10 rays is always the equator. Because that?s the way it1 works. And that?s the nature of the angle of of the?12 239 Marc: That that?s shape?13 Katie: Mmm hmm has to be, that?s what makes the equator14 Cameron: The equator?s not always the closest part to the sun15 Marc: Right but it?s always getting the most direct sun.16 Cameron: Not always.17 Marc: No no it?s true.18 Cameron: That?s what the tropics are about.19 Tom: Yeah that would only be true if?20 Steve: That?s that?s ? it?s some sort of area?21 Marc: Right right I see.2 Katie: You?re right, but still that area?the belt. The fat-belt.23 Leslie: So why does the tilt matter?24 Steve: Well they think it?s ?cause the (laughter) ? well here?s the25 thing, now I have a problem for all you people you and26 your filter (laughter) is that that?s fine I?ll accept your27 filter all if you can explain to me why even when the28 earth is demonstrably further from the sun we don?t have29 any differences in temperature between north and south30 pole?31 Tom: Why does angle matter more than distance?32 Vic: Or why is distance irrelevant?3 Steve: Or- right, why ? how can distance be irrelevant if the34 earth is much further from the sun at some points in its35 orbit and the average like if pick some spot latitude and36 long and like halve the southern and northern37 counterparts for it--?38 Vic: But wait wait wait--39 Steve: But if it?s going that much further farther away why is the40 temperature not that much different?41 Vic: But wait wait-- I have a thought right ? this is not a42 question of like, that we can, like if there was a fire in43 that fireplace and the farther back I move from the4 fireplace the drop in temperature? there?s atmosphere45 involved. The heat?s traveling in a different way. So that46 it?s not a question of, like, radiant heat. The heat that47 we?re getting from the sun is a question of light, right?48 Katie: Yeah because that once we get into space it?s cold out49 there.50 Vic: Right. Heat?s not traveling through space in the way that51 radiant heat does.52 Marc: How does heat traveling through space?53 Katie: As light.54 Vic: As light. As energy. And and then the atmosphere bends5 the light.56 240 Katie: Once it hits something [Tom: that makes sense to me]57 that gets [Marc: heated up]. It?s like And then it can?t58 get back out.59 Amelia: Right. It?s trapped.60 Vic: Because of the atmosphere.61 Katie: Once it turns from- -I don?t really understand this but it62 seems like it turns from light to heat but it?s all energy63 but it?s64 Vic: We?re into the angle theory.65 Marc: It turns from energy to heat. Not necessarily to light to6 heat because there are other forms of non-visible light.67 Amelia: Okay. So therefore when the68 Katie: Energy in the form of light69 Marc: Right gamma and ? ?which is nonvisible light.70 Infrared.71 Amelia: Which would might wonder why there wasn?t necessarily72 why there wouldn?t be a huge different in temperatures in73 the northern and southern hemispheres.74 Cameron: So are you saying?75 ?: Yeah?76 Cameron: So are you saying that the angle doesn?t matter?7 Steve: No, I?m just saying that if ? if we don?t think distance78 does matter then we have to be able to explain why79 distance doesn?t matter. And why--80 Amelia:He?s tough?he doesn?t let you get away with anything.81 Steve: ?even though the earth is much further from the sun at82 some points in its orbit summer temp maybe is?83 Marc: But we don?t know about that ? it?s possible that there is84 a different average temperature.85 Steve: Well but you were just saying that you didn?t think there86 was.87 Marc: Well I asked and someone said: did you read the8 Antarctica book? And she said??I don?t deny that it can89 get pretty damn cold down there?it?s just the question is90 what?s the difference.?91 Vic: Well it- the other question is then why is then the92 different planets does it seem to get colder the farther93 away from the sun? Right?like Pluto is like frozen94 solid.95 Steve: Is that just because they have different atmospheres?96 Vic: That?s exactly what I?m wondering is that is it a question97 of distance?98 Marc: Well clearly it has something to do with distance because9 we don?t feel the heat from other stars?I mean distance10 has something to do with it.101 241 Tom: What?s the temperature on Jupiter- I mean it seems the102 gas?103 Vic: What?s the temp on Jupiter [singing]104 Steve: What?s the moon?s temper?what?s the moon?s105 atmosphere like.106 Marc: There is no atmosphere.107 Vic: Right.108 Steve: that?s not true?there?s atmosphere on the moon.109 Marc: There?s no atmosphere there.10 Vic: A really reall? it doesn?t enough gravitational force all11 on its own to have significant atmosphere. It has very12 very thin atmosphere.13 Cameron: So what?s the difference between temperature on the14 moon between day and night?15 Marc: Oh it?s huge! It?s enormously huge. [Why?] There?s no16 atmosphere to trap in the energy?it?s like the greenhouse17 effect.18 Tom: You can?t have temperature without an atmosphere?19 Steve: But I thought we couldn?t have heat without [couldn?t120 have what?] heat without atmosphere.121 Marc: No, see?I?m not sure I ever signed up for that.12 Marc: No there is such a thing as radiant heat?that?s what the123 sun?124 Steve: But if it?s in a vacuum, I learned last week that space is a125 vacuum.126 Vic: That?s what I hear.127 Katie: I learned that science doesn?t suck.128 Cameron: But if you put something on there, like a thermometer,129 which is measuring the temperature, it?s hotter in the day130 because it?s absorbing the131 Vic: light and rays and things. Right ?cause it?then there?s132 no atmosphere at all to filter it and it?s just absorbing13 everything.134 Marc: Vacuum means, by the way there?s no? I don?t know135 first of all , I was going to say something that there?s no136 mass but these electromagnetic waves they don?t have137 any mass really so you can still call something a vacuum.138 I don?t know we?re getting technical?there?s a lot of139 energy in space! It?s filled with energy.140 Steve: Right?right, but that doesn?t make it heat.141 Tom: Yeah weren?t we talking about if you?re just completely142 in outer space, not exploding (laughter) it?s we decided it143 was meaningless to talk about heat isn?t that right? And14 so presumably isn?t that the same thing if you?ve got a145 planet without an atmosphere? Then it?s just an object in146 242 space? That?s just like you standing there in your space147 suit trying to measure the temperature.148 Marc: but it?s HOT on the sunny side of the moon?it?s hot.149 Tom: It is?150 Marc: yeah.151 Steve: So the moon has enough atmosphere to create heat.152 Cameron: So I think what we?ve learned here is that, [Katie (to153 Marc?): How do you know it?s hot?] uh, is that the154 atmosphere helps, like, mitigate temperature change.15 ?: The surface itself? We can do that also with looking at156 other planets, right.157 Tom: Well but then it?s reflected too, right?158 Marc: Say again (to Katie?)?159 Katie: Like if we know what the atmosphere is like on other160 planets and they have--161 Marc: Like Venus for example, Venus is very hot162 Amelia: We are mostly water and it does reflect light which163 bounces back and forth.164 Marc: Yeah yeah?the atmosphere reflects most of the light?165 Katie: Yeah if it were too hot up in here we would be just16 Marc:We would fry.167 Amelia: Well the oceans would evaporate.168 Katie: yeah that?s I?m trying to say.169 Marc: The oceans would boil the four horsemen?170 Steve: By the way when we?re done with this I have to tell a171 story about what the priest said at mass today?it was172 nothing about prostitutes or anything like it was last year.173 Amelia: Did he talk about the four horsemen apocalypse?174 Steve: we talked a little bit about the apocalypse? it was175 actually pretty good. [Conversation turns to discussion of176 weekly happenings.]17 Vic: [Yelling to get attention] Heat of the sun and the moon178 and the stars!179 Steve: Alright. Heat of the sun and the moon and the stars.180 Leslie: Okay?put a thermometer. It?s gonna do?181 Katie: I?m pretty sure that the mercury?s gonna leak out.182 Amelia: And then it?ll float in these little silver balls.183 Tom: How does a thermometer work again?184 Katie: That?s pressure ? a thermometer has to do with pressure185 so it wouldn?t do anything in a vacuum.186 Marc: No a thermometer isn?t pressure- barometer is pressure.187 Steve: How do you get the mercury to move?18 Marc: Okay- what happens is, your particles have to interact189 ?cause I remember as a kid reading somewhere that if you190 could actually get to the center of the sun it?s so gaseous191 243 the particles are so disparate that you actually freeze to192 death because there wouldn?t be much interaction193 between you and the particles of the sun.194 Steve: You?d need a hell of a space suit to get there though.195 Marc: That?s what I?m talking about. And you be blind by all196 that light. But actually there?s no particle interaction so197 I?m assuming that- I?m imagining that if you take a198 thermometer and put it into the vacuum of space there are19 very few molecules to interact with your thermometer20 and that?s why it?s cold out there. So the question201 is?and I remember this, this is a question in202 science?how does energy travel? That?s ? they tried to203 prove there was an ether in space! [right] And they204 found out there?s no ether, so how does energy travel in205 space? [right] It?s electromagnetic waves.206 Amelia: What do what do we call this stuff?207 Katie: I wish you were a little smarter.208 Steve: I do too.209 Amelia: Most of space is that stuff and there?s that other stuff.210 Steve: But- alright so like thermometers in space?21 Leslie: No no?just a thermometer on earth, how would that212 work?213 Steve: Okay?214 Tom: What is it about mercury, what happens to it?215 Marc: well it expands. But it?has to be hitting the bulb, I mean216 like the heat that the gas- the air. [it?s what heat it]217 yeah?what?218 Tom: Heat is like the ?219 Marc: Heat is a measure of the amount energy?the motion of20 molecules.21 Tom: There has there has there have to be molecules moving to22 measure heat. That?s right.23 Steve: But how do they?wait a minute?look.24 Katie: So you go into space where there?s a vacuum and there?s25 no molecules out there to interact with the little bulb at26 the bottom the mercury inside, it?s not gonna measure27 anything.28 Marc: That?s right. And that?s why it?s cold in space. Because29 your body doesn?t feel any of those molecules either.230 Steve: Wait a minute. Because sometimes you have [Katie: I?m231 afraid we?re guilty of reification but ok] but sometimes232 you have thermometers that are in the sun and in the23 shade right next to each other and the sun one is much234 hotter.235 244 Marc: That?s because the air surrounding the hotter is moving236 faster and in the shade.237 Amelia: And if the vacuum has no air.238 Marc: You?re right, then you wouldn?t measure anything.239 We?re agreeing.240 Steve: Does it seem like Weitz agrees with everyone?241 Katie: Nuh uh he?s been fighting with you all afternoon.242 Cameron: Even when you agree.243 Amelia: Yeah- he even says for you to shut up (?)24 Leslie: Okay guys I?ve got a thermometer in space, one is in a245 box and one is facing the sun so one can?t see the sun and246 one can. Are they gonna measure the same non-247 temperature?248 Cameron: What?s in the box?249 Leslie: The shade.250 Marc: Well is it the vacuum of space?251 Steve: Lava.252 Leslie: Still in the vacuum of space.253 Katie: Wrapped in leather.254 Marc: No no wait a second but you?re right though because um25 for example, solar panels that face the sun?like if you256 had a satellite with a solar panel and it?s facing the sun257 the carbon fibers, everything?s expanding. That?s how258 they sometimes lose these satellites because?so the259 energy260 Amelia: Marc talks too much.261 Katie: is he like this in every class?262 [Laughter, jokes about Mr. wizard and kids.]263 Marc: So it must be - it must be- a temperature. Well, there?s264 heat in space. I mean your satellite.265 Vic: The object is absorbing the energy by the light.26 Marc: So would the thermometer absorb the energy?267 Vic: Why not?268 Marc: Well then- then we have to change our answer then the269 thermometer would rec??270 Vic: I was going to say that all along?I don?t know what you271 guys think (?)272 Katie: I?m not saying that? it seems like the way the273 thermometer works though it seems like it wouldn?t274 register. It might275 Tom: I don?t quite understand how a thermometer works276 Katie: Well?27 Tom: ?Cause we?re talking about heat.278 Katie: Weitz?279 245 Marc: What if the what if the what if the energy that?s ? the280 gamma ray and the infrared and whatever?what if all of281 that electromagnetic energy excited the mercury in the282 ball and it expanded? Then it might measure something.283 Katie: IF that?s how a thermometer works then, ok.284 Steve: How do we?is that how a thermometer works?285 Vic: Is there a reason that a thermometer can?t absorb energy?286 Marc: Is there a reason why? That was your question? [right] is287 there a reason why it might not absorb?28 Vic: And then there?s the question of whether or not.289 Steve: What?s the intake on a thermometer?290 Marc: It?s a metal bulb ? it?s just291 Steve: It?s a metal bulb that?s exposed. And like the292 thermometer could be put in our mouth.293 Katie: A thermometer that you put in your mouth?it reacts294 differently than a thermometer that you have outside295 because if I if I am right the thermometer I have when296 I?m sick it does not measure how cold my house is. Am I297 makin any sense?298 Vic: I dunno.29 Katie: When you when you don?t have it in your mouth and it?s30 not actually touching anything301 Marc: Right then it yeah302 Katie: It might be warm or cold but it doesn?t say my house is ?303 [yeah]304 Amelia: How many ways are there to measure heat?305 Marc: But but mercury thermometer does?sure it does. You306 shake it out and?307 Leslie: Amelia just asked?308 Marc: Oh. What was your question?309 Amelia: How many ways are there to measure heat?310 Cameron: That?s only one kind of thermometer, right?31 Katie: That?s what I mean that?s what I?m tryin to say. The312 difference-313 Cameron: You?re saying something different.314 Amelia: ?Cause that?s not what they use in space to measure315 temperatures like on the moon. What?why are we even316 talking about this?317 Vic: Are we completely distracted?318 Katie: She asked us what a thermometer would do in space.319 Amelia: But she didn?t say what kind of thermometer.320 Marc: But in order to measure heat you have to have something321 reacting with the environment. [ok] so if it?s not mercury32 it?s? silicon in a chip or something- something has to be323 246 reacting with the environment and my question is [well324 my] is there anything in space to react with.325 Amelia: But temperature is measured on the moon is it not?326 Marc: That?s what I?m- I agree with you.327 Amelia: So how do they do it? She?s not going to tell us, I?m328 sure. How- how is temperature measured on the moon?329 If it?s been done then how?30 Marc: But the question is why is it so- why is it so cold? It?s31 measured some way! It?s measured some way?let?s, I32 can agree it?s measured some way but take that33 measuring system and put it in space. Is there anything34 that it can react with? Is there any particles in space?35 wait, what?s our question again?36 Leslie: We put the mercury thing up there?a normal thing up37 there?it?s gonna have a reading on it. Is that reading38 going to tell you the temperature or is it just?it doesn?t39 work any more?340 Marc: Well it it should, I mean?it?ll be very very cold but341 there?ll be some heat there.342 Steve: Mmmm. I disagree.343 Katie: The question, I think, is will the thermometer measure34 that heat?does it work in space?345 Marc: There?there aren?t many particles for it to interact with346 which is why it?s so cold I guess.347 Steve: It?s a vacuum though.348 Marc: There aren?t any particles though.349 Steve: But the moon has? if it?s in space?350 Marc: The moon is a rock?it interacts with the gamma rays351 [in background Amelia, dark matter?]352 Steve: Neil Armstrong bounces. On the moon.353 Vic: That?s correct?but yeah that?s gravity and not354 necessarily the atmosphere.35 [Amelia, in background: ?only this much about dark356 matter?and if they don?t know and by they I mean the357 scientists, how are we supposed to know.]358 Steve: If we didn?t have gravity we?d ____ on the moon.359 Marc: That?s correct?so you might, one could argue that the360 moon has one sixth the atmosphere since it has one sixth361 the gravity.362 Leslie: That was Amelia?s? I didn?t hear your last comment.363 Amelia: Oh I was talking about?I mean, isn?t most of space dark364 matter and then some of space is dark energy, right? Or365 something like that?36 Leslie: We don?t know.367 247 Amelia: We don?t know?like we don?t even know what dark368 energy is and barely know what dark matter is, and so if369 scientists who study it don?t know then how are we370 supposed to know what?s happening.371 Leslie: Well the thing is either our theories are wrong or there?s372 mass we can?t find, you take your pick.373 Amelia: But what I?m saying is, nobody knows374 Leslie: Right. Yeah.375 Marc: I still think it has to do with the amount of particles to376 interact with?in space there are few particles so there?s37 very little heat cause you?re not feeling it it?s not?well378 not very little, yeah? but on the moon it?s a big rock so379 it?s taking all of this energy and it?s interacting with all of380 this energy that?s coming at it.381 ?: Something about atmosphere382 Leslie: Well what?s so special about the atmosphere that helps it?383 Tom: Well there- there wouldn?t be a temperature around the384 moon but the moon itself?385 Marc: The moon itself has a temperature.386 Vic: Wait wait wait?no no?this is387 Katie: You could plunge a thermometer into the moon. Like a38 turkey [laughter] into one of the crevasses of the moon.389 Marc: Up the moon?s butt. And baste the moon a little bit.390 [break]391 Vic: The problem is the problem is?the lack of significant392 atmosphere on the moon means that one side is going to393 be very hot and the other side is going to be very cold.394 Tom: Because the atmosphere tends to preserve the395 temperature.396 Vic: Right. The atmosphere is going to stabilize it the earth is397 within a certain temperature. And then there are other398 weather patterns that happen in the atmosphere that might39 move that energy around.40 Marc: It also serves to reflect.401 Steve: I think an atmosphere matters because radiant light hits402 the one sixth, whatever, atmosphere of the moon there are403 particles to hit? that that light can, I don?t know,404 whatever, I?m making it up not? triggers molecules to405 move, creates heat.406 Marc: but that?s not the only source of heat that heats the moon.407 The moon itself absorbs a lot of the radiation that the sun408 is giving off.409 Steve: Right but that?s the way it?410 Marc: the ground absorbs radiation.41 ?: Why does it need to be atmosphere?412 248 Steve: Well I guess- the reason I?m thinking atmosphere matters413 is because if we don?t have atmosphere?if you don?t414 have like ? spaces of vacuum [the rock] right right or415 where you have. So a rock-lava-David? David? is in416 space? does he get hot?417 Marc: Yeah.418 Tom: David can have a temperature because because he is419 made up of molecules which are420 Steve: So if David passes in back of, like, Venus de Milo, and is421 in the shadow for like a little bit and then moves back42 into the sun, David warms up?423 Marc, Tom: Yeah. Pretty much.424 Tom: That makes sense to me.425 Marc: That makes perfect sense.426 Leslie: Does he keep warming up indefinitely?427 Steve: Right.428 Marc: No because there?s finite amount of?he would reach a429 stable point.430 Leslie: Why?431 Vic: Yeah- why?432 Vic: There?s no way for you to give off that heat?there?s no43 way for you to radiate that heat.434 Marc: No but you do- but you do radiate the heat.435 Tom: you don?t heat up indefinitely436 [Many voices.]437 Marc: Because all matter would evaporate.438 Steve: David explodes eventually.439 Marc: Ok, yeah- eventually the earth explodes?but that?s not40 what we?re talking about.41 Vic: The earth explodes?!42 Steve: Yeah- that?s what the priest was talking about.43 Marc: That?s only if we sleep with prostitutes.44 Katie: The priest said the Earth was gonna explode?45 Steve: You shouldn?t believe Pentecostals.46 [Discussion of a recent field trip to a church.]47 Leslie: Well is this what?s causing global warming?just that the48 sun keeps shining on the earth?49 Marc: No it?s the thickening of the atmosphere that?s trapping450 more and more.451 Cameron: But the energy can?t get out.452 Vic: Yeah why would why would- that?s would, I guess that?s453 true, so why would the energy have to be spent as heat?454 Like radiated as heat from the David floating in space?45 Or could he not give off his heat?456 Cameron: So why can?t we radiate heat out?457 249 Marc: Well we do radiate heat out but the increasing density of458 carbon dioxide is trapping ?459 Vic: We?re not worried about the Earth we?re worried about460 David.461 Cameron: I?m talking about a guy floating in space.462 Tom: Oh so global warming?just forget about that.463 Steve: For the time being.464 Marc: David does radiate heat. David does radiate heat.465 Amelia: But only for a while, right? Is he radiating it as fast as he46 [?] it?467 Marc: Once he reaches a stable point?468 Katie: you can?t play that card [?]469 Marc: why?470 Marc: Okay? let?s? let?s say David is in a shadow, right?471 Okay- he enters the sun. The sun bombards him with all472 this energy right? So in a second it?s now at 5 degrees.473 Can it radiate heat that fast? No. So in the next second474 it?s 10 degrees. It?s now radiating a little bit more heat475 but there?s more energy coming in. So it gets to 15476 degrees. But at some point it?s radiating enough heat to47 stabilize at 20 degrees.478 Steve: But why?479 Cameron: What?480 Marc: Or let?s think of think of like a, think of like a basin, ok?481 Think of a tub. With the drain open, okay? The drain is482 open. Now if I open the spigot [Uh huh.] ? if I open it483 too slow then the tub doesn?t fill. But if I open the spigot484 fast enough there?s water filling up the bottom, and yet485 some is also draining out, right? [Right.] If I open the486 spigot up fast enough it doesn?t matter if the bottom is487 open, the top will overflow but at some point if I reach48 the right point the tub could stay at a certain level, even if489 water?s going in and water?s going out, right? If they490 came in at the same rate [Steve: Right, but?] the tub491 would fill up.492 Steve: But that?s ? what?s David?s drain?493 Vic: That?s?this is my question. What?s David?s drain?494 Tom: Well, what?s the sun?s drain? The sun is clearly radiating495 heat and energy.496 Marc: Yeah I mean that?s just the?497 Steve: The sun is radiating light.498 Vic: I want to?49 [Many voices.]50 Marc: And gamma rays (in response to Steve) and x-rays and all501 these other things.502 250 [Amelia squeals to imitate being bombarded with rays.]503 Steve: The sun is giving off light rays.504 Marc: It?s giving off a whole?505 Cameron: Why is the sun so special that something else can?t give506 off energy in whatever form?507 Steve: Well the sun?s giving off light?508 Vic: so it?s generating509 Marc: and radiation and stuff.510 Cameron: So it?s all about the light.51 Steve: yeah right I think it?s about light.512 Cameron: that?s the only kind of energy.513 Vic: no no there?s radiations and stuff.514 Marc: let?s say the spectrum the electromagnetic spectrum.515 Leslie: If you say light you don?t necessarily have to mean516 light?517 Steve: I just mean like, rays.518 Vic: Radiations.519 Steve: So I thought that we were saying that ? or y?all were520 saying that the Earth is warm North v. South we have521 seasons because of the way that light interacts with the52 atmosphere, right? And filters it at different angles.523 Marc: The atmosphere will reflect?reflect not absorb?will524 reflect more sunlight depending on the angle at which it?s525 tilted towards the sun.526 Steve:If the earth didn?t have an atmosphere.527 Marc: Far less light- far less energy- would be reflected and the528 earth would be a lot hotter.529 Vic: Oh oh oh oh oh oh oh oh . Oh oh oh .530 Marc: The Oceans would boil the apocalypse.531 Tom: If the earth did not have an atmosphere there would be no532 seasons, right? Because.53 Marc: No no?yeah yeah yeah.534 Vic: I had just had an I had an idea well- or at least about why535 distance is at least partly significant in terms of the536 amount of heat that an object absorbs, right??that ? that537 if you?ve got a source of of the radiation stuff, then it all538 goes back to surface area again. So that if you?re Pluto539 and your?re this far away, the amount of surface area that540 you have exposed in terms of this circle that?s radiating541 heat?the closer that you get the more of your surface542 area is going to get sort of?543 Marc: This has to do with size?Pluto?s much smaller than the54 Earth.545 Leslie: Vic, do you think Marc understood you?546 Marc: I?m sorry.547 251 Vic: I?I don?t think he did.548 Leslie: Marc do you think you understood Vic?549 Marc: I thought I did, but given his pause I don?t think that I50 did.51 Vic: Alright?if we can go back to the moon, right? [ok] If if52 the moon gets in the way of the sun and it blocks out the53 entire sun it can only do that because of the distance54 because of the relative distance between the Earth and55 stuff.56 Marc: And the relative size.57 Vic: Right. So that- if the moon were closer [to what?] to the58 sun they would block out less of the sun? or or more!59 [laughter.] Or more! Or less!560 Leslie: No wait?more or less?which one? Both?561 Steve: It would block out less of the sun.562 Marc: Think about putting your hand on a screen?making a563 shadow puppet. The closer you get to the light source?564 Amelia: The smaller it gets.565 Marc: The bigger the puppet.56 Amelia:No.567 Tom: The closer you get to the source of the light?568 Marc: My god we?re getting? I don?t know now.569 Vic: Right right?570 Amelia: Oh the source! I?m sorry I?m sorry.571 Vic: Closer to the light you?re absorbing more of the light.572 Marc:That?s right.573 Vic: Your hand hasn?t changed size?now the closer it gets to574 the screen the more it absorbs. That?s exactly what I?m575 saying ? so the clue (?) this hand puppet far away576 absorbing a little bit and that ? Mars is the one that?s57 closest to the sun so it?s absorbing more of the thing578 Marc: Over those huge distances it makes a difference.579 Vic: Regardless of how?yeah?regardless of how much580 surface area.581 Marc: That?s right, but then over such large distances distance582 makes a difference but given just the tilt of the earth I?m583 thinking that the tilt has much more to do with it.584 Vic: No I?m just talking about why- why distance is still585 significant.586 Marc: Well of course distance is absolutely significant.587 Cameron: Distance is not significant it?s the amount of diffusion58 that happens within that distance.589 Vic: Okay.590 Leslie: What do you mean ?amount of diffusion??591 252 Cameron: Like?when my hand is closer to the projector?with the592 projector the lens makes the light go like this?so it?s593 more diffuse when you get out towards the edges and the594 band, width is narrower when you?re closer to it. [Marc:595 radiates]596 Leslie: So it gets weaker as you go out.597 Cameron: It?s the same amount of energy but it?s spread over?598 Leslie: Is it solely because of what Vic said?is it just because59 it?s going over more area or is it also just losing energy as60 it travels?601 Cameron: It?s probably losing energy as it travels, too.602 Vic: Wait though it?603 Cameron: Well, it?s gonna hit other things.604 ?: You?ve got (?) atmosphere.605 Vic: Yeah ok sure.606 Vic: I?m thinking in terms of stars and stuff?607 Marc: Light weakens the further away you are, that?s why we608 have brighter stars? well one of the reasons why we609 have brighter stars and dimmer stars is that the energy610 that the light has decreases.61 Leslie: But is that because it?s just traveling further or is that612 because ? well, how should it decay if it?s just because of613 distance?614 Tom: Inverse square, right? Because it?s?uh?615 Marc: Because you have three dimensions.616 [Laughter.]617 Leslie: [To the tape recorder.] Okay?Tom is taking his hands618 and flinging them apart over and over again.619 Tom: Don?t you see? Can?t you see?620 Marc: I gotta listen to these tapes.621 Marc: what question are we pondering?62 Leslie: I ? I happen to know how fast light decays?and if you623 could tell me what it would be if it were only due to624 area?that it takes up?that the area that the light?s going625 into is getting bigger?626 Tom: Right right right! That?s it the area is getting bigger, so627 like?damn.628 Marc: So it would have to illuminate an ever greater source of629 area so each individual point gets less.630 Cameron: That?s what I was talking about earlier.631 Leslie: That is?so I?m wondering why Tom thought it would be632 distance squared. So if I?m close to the sun it?ll be x63 bright , if I?m twice as far away it will be one fourth.634 Marc: [Sighs.]635 Vic: So that- you win. It is distance.636 253 Marc: Look the distance between earth and Pluto has to do with637 distance but the difference between winter and summer638 has to do with tilt, not distance.639 Steve: But tilt is insufficient by itself. Tilt ?640 Marc: I mean ap?I mean angle of incident energy. That is641 correct.642 Marc: So then I can guess maybe distance has a component.643 Steve: I?m troubled by David. I want to know why he radiates64 heat.645 Vic: You mean how he gives off heat?646 Steve: I want to know why he gets warm and why he can647 radiate.648 Marc: He reflects?I?m not sure that he radiates. Well?649 Tom: He will reflect.650 Marc: He?ll reflect him because we?ll be able to see him.651 Steve: But where will it go?652 Marc: That?s how we see it. We see it because he reflects.653 Steve: But it?s not light it?s heat.. it?s not heat it?s light654 Leslie: Does it get hotter at all? Does he absorb any of it?65 Marc: He absorbs it?that?s what gives him a temperature that656 we can measure.657 Leslie: Ok?why does he stop? Or is he always going to keep on658 absorbing it.659 Steve: Right. Because there?s no way?there?s nowhere for60 that?61 Marc: His temperature will change depending on his relation to62 the energy source. If he?s moving towards the sun he?s63 getting hotter if he?s?64 Vic: Right but to borrow your bathtub metaphor right if he65 keeps?if he keeps absorbing energy without being able66 to?67 Steve: He?s going to overflow.68 Vic: He?s going to overflow and blowup.69 Marc:But he is?he is ? I could imagine?I could imagine670 perhaps-- tiny thing, MAYBE, blowing up. But a certain671 size would be able to reflect that at a good enough rate672 that it would be able to stabilize.673 Steve: But if he gets hot?I?ll buy that he reflects?but if he also674 gets hot?either there?s some way that he gives off heat675 or676 Cameron: I say that he?s radiating heat.67 Steve: But how can he radiate heat?678 Cameron: How can he not radiate heat?679 Steve: There?s no where for the molecules to go (?)680 254 Marc: Ok but this is very tricky. Electromagnetic radiation681 travels in a vacuum. How does that happen? I don?t682 know. But it happens. Now if we want to sit here and683 think?I mean that?s684 Steve: That?s what happens the light hits David?on David?it,685 the light becomes heat and then it eventually becomes686 something other than heat and leaves David?687 Marc: Ah- no energy hits him. It?s absorbed. It?s also reflected.68 And as it?s reflected it takes some of it?s energy with it in689 the form of a different type of energy because ?690 Vic: Right right right ok?again what we keep getting at or I691 think that what my trouble is with Steve here is again692 Steve: Not with Steve, with my concept693 Vic: I?m sorry?your concept. I am in agreement with your694 concept.695 Steve: I mean I understand having problems but like let?s696 maintain boundaries (laughter).697 Marc: So what happens is?this is the sun coming in and it?s698 very wavy ? it looks like a nice ruffles potato chip,69 right?it comes and it hits the David and some of it is70 absorbed so its molecule are beating right and some of it701 is reflected in the form of something less wavy.702 Cameron: The problem is, I think, the distinction between energy703 and heat.704 Steve: No, that?s not the problem.705 Tom: But I still don?t understand (Steve: Tom is with me) so706 that the energy from the sun is always striking David and707 some of that is being reflected.708 Marc: That is correct.709 Steve: So David is accumulating energy.710 Marc: At a certain rate-- in one second it gets a certain amount71 of energy in the second second it gets the same amount of712 energy713 [Many voices.]714 Steve: So if it?s always in the sun it?s going to continue to715 collect infinite amounts of energy?716 Tom: It would end up start reflecting as much energy as?717 Marc: Think of it- think of it like a rhythm, ok? Boom boom718 boom boom right so- it gets energy and it reflects and it719 gets energy and it reflects?so it?s constant?it?s just its720 just it?s just stable.721 Steve: It?s not stable! [many voices]72 Marc: Then it would not it would not it would not! you?re723 thinking of something that?heat is measured by ticking,724 right? Tick tick tick ok? what you?re saying is the sun is725 255 hitting it and it?s constantly accelerating because it?s726 constantly getting new energy, right? Tick-tic-tick-727 tktktktktk! Pow! Right- that?s not what?s728 happening?it?s just tick, and some energy comes in just729 as it?s about to slow down it gets new energy so it?it?s730 that energy that keeps it at that constant rate.731 Steve: I don?t buy equilibrium.732 Marc: Uh uh?73 Steve: I reject that. I reject the assumption of equilibrium.734 Vic: Because then David would never ever change735 temperature.736 Marc: It would if it got closer or farther away- lets say that it?s737 traveling.738 Leslie: Let?s keep David still! Let?s keep David still for now.739 Marc: David is still- David is not moving. Energy comes in?it740 vibrates, right?741 Leslie: So did David heat up or ?742 Marc: It did just heat up, ok? ? now what keeps it going? It?s743 the next calorie calorie of energy that keeps it74 going?without that calorie of energy it cools down.745 Some of it some of it set the molecule in motion and746 some of it reflected away. And then the next calorie747 comes?748 Steve: Wait wait?right before that last- the second burst of749 energy it was at zero again?750 Marc: Well maybe.751 Steve: David?s back to zero.?what you?re saying is energy752 hits?one?half leaves half [half stays] stays?[that?s753 right] and then sort of withers. [then meanwhile the next754 one comes in]. I reject that too but I understand your75 logic.756 Marc: At least I?ve been heard.757 Leslie: In your system is energy conserved?758 Marc: Yes?because some of the energy has been absorbed and759 some has been reflected and that hopefully should equal760 the same amount of energy coming in.761 Leslie: Ok?the energy that?s absorbed is it lost forever or does762 it somehow escape back into the universe?763 Marc: Ah?is it absorbed forever? Well it?s stored in the764 temperature of this thing! If I could take that and heat765 water with it, I?d have recovered the energy.76 Vic: Huh?767 Marc: That?s how we?this thing has energy- it?s like it?s like768 it?s like a computer ? it?s memory. It?s storage.769 Steve: Does that mean it will heat up?70 256 Marc: No ? because it?s not, it?s not, the rate of the vibration of71 the molecule is not increasing infinitely it?s just getting72 energy. Without that energy73 Steve: Molecules get energy and stop, molecules get energy and74 stop.75 Tom: And why do they stop?76 Marc: Well they reach a stable?you?re assuming that it?s77 preordained that this one , I mean, if the energy?s coming78 in too quickly it will, I mean?it?s not preordained that79 it?s going to tick like this I mean maybe it will tick like780 this?maybe it?s really oneoneoneone? but eventually781 it?s going to be reflecting it at a stable rate.782 Cameron: I don?t think reflecting is the right word.783 Marc: or radiating.784 Cameron: It?s getting rid of energy somehow and part of your785 problem is that you?re assuming is that it?s a linear- it786 keeps getting more heat and it keeps reflect?or getting787 rid of , or excuse me energy, keeps absorbing more78 energy and keeps reflecting energy at the same rate.789 Steve: I don?t understand what?790 [Many voices]791 [Marc simulates being pushed like a pendulum.]792 Marc: Just give me a push that way ok? Good. Now I jumped793 all the way here.794 Leslie: Now wait?if you start with some energy, why did you795 slow down and stop over there?796 Marc: Well, ?cause I don?t know?molecular forces? because797 that?s the only amount of energy he gave me! So come at798 me again?79 Tom: Wait no no no?you slowed down and stopped because80 you were running into something.801 Marc: I was running into something the the the?David has802 intermolecular forces, ok? So it has?the weak force the803 strong force it has these intermolecular forces, it pulls it804 back right? So push me again.805 Tom: SURE! [Laughter.]806 Marc: And I don?t mind?right and if he punches me harder I807 go farther but if he?s punching me at a constant rate I will808 only go the same distance every time, I won?t eventually809 go out the door unless he starts punching me harder?but810 I?m not accumulating energy here I?m going to the same81 spot every time.812 Leslie: So you?re not accumulating energy.813 Marc: That?s right?I?m not accumulating energy.814 Leslie: Then where is the energy going?815 257 Marc: What do you mean? He?s just sending it out and I?m816 absorbing it and I?m going back and he?s sending out the817 same amount818 Steve: But if you absorb it that means that you keep it [Marc:819 keep it]820 Marc: Well the energy?s going into my running back and forth821 ok? this is where the energy?s going it?s kinetic energy!82 I?m now running back and forth, right? But I?m going to823 get tired unless he pushes me again I?m not going to have824 the energy anymore?825 Steve: But the energy doesn?t?I?m no physicist?but I don?t826 think energy just disappears like that.827 Marc: Where is it disappearing? it?s stored in kinetic energy?if828 I?m on a treadmill I can turn a turbine. If you put me on a829 treadmill you?re using my running energy.830 [Voices.]831 Marc: Wait wait wait- stop a second! This is where the energy832 is- it?s kinetic energy this is usable energy!83 Amelia: But Marc if you?re still the energy?it?s still in you.834 Marc: I don?t know where that?in the example he?s pushing835 me right? And you want to836 Leslie: Let?s think of when you turn around?are you moving?837 Marc: That?s potential energy?right? I?m about to go838 BACK?if you could stop me here you could put a839 treadmill?I have the ability to work the treadmill.840 Vic: I?m having serious problems ? reconciling the metaphor841 has taken on levels of complexity.842 Marc: When you stretch a rubber band is there energy in that843 rubber band? Yes?it?s the amount of energy84 [Jokes and laughter.]845 Steve: Marc I think you might sit down. [To Leslie] Can you846 give us a little bit of guidance.847 Leslie:Um?I I sense that the rest of the group disagrees with848 him (Marc).849 Amelia: I don?t.850 Cameron: I agreed with Marc too until he started talking about851 potential and kinetic energy and then I wasn?t buying852 that.853 Vic: I was on the fence.854 Steve: I was so not on the fence.85 Leslie: Can you illustrate in a way that makes sense to856 Marc?and Marc you?re going to have to listen?[I?m857 listenin!] and I want you to be able to repeat Steve?s858 argument back to him, not in Steve?s words, in your own859 words. [Ok]860 258 Steve: So?David?s in space David is hit by energy [x] x861 amount of energy. Some of that energy is reflected off862 for some other?in the form of light back somewhere863 else. The rest of it hits David and is absorbed by David864 and David?s molecules start to move more quickly.865 Tom: So at some point- perhaps when David?s molecules start86 moving quickly enough, he actually starts to radiate867 energy in a different way.868 Steve: But then the question becomes: if he?s, so if only a part of869 that energy is what?s reflected off in the form of light (a870 few jokes) um.. but if the light continues to hit and only a871 part of it goes off then [explodes or melts] is heating up,872 right? And then my question is, and it?s really just a873 question, because David?s in space, so he?s not874 surrounded by molecules that could be heated, so they?d875 be, so he?d be able to radiate, Marc, how does he, how876 does this rock have the capacity to radiate anything if87 there?s nothing except for light, space and David?there?s878 nothing for him to radiate for heat to be transferred out.879 So?I think, the way I see it is that the light comes in,80 part that?s reflected off, the rest of it sticks in David, and81 because energy doesn?t disappear David just continues to82 heat up and maybe explode. I don?t know?83 Cameron: What happens when he explodes?84 Steve: I think when he explodes, then there are smaller chunks85 of David.86 Leslie: The moon, so far, has not exploded.87 Tom: I mean things don?t explode so we?re missing something.88 Steve: Right, but there?s somewhere?if David is really in89 space, and so he?s surrounded by a vacuum and it?s a890 perfect vacuum, then there?s no other molecules891 surrounding him that can carry radiant heat.892 Cameron: Ok- I have a question. Marc said that radiant heat is not893 the only way it can expel energy.894 Steve: Right- exactly--- no and that?s what I?m looking for, is I895 just need some help on where.896 Marc: Let me ask you a question?how did that energy get to897 David?David?s in a vacuum?how did that energy get to898 David in the first place?89 Steve: I?m not fully convinced that David even heats up because90 he?s hit. I?ll buy that he?s hit by energy and I?ll buy that901 he sends some of it off [that?s fine] but then does he not902 absorb any of it? And if he does then903 Marc: He does?he absorbs it and he heats up?he goes from904 some temperature to a higher temperature.905 259 Steve: What?s to stop him from heating?906 Marc: He heats to the point that he heats.907 Steve: That?s teleological.908 Marc: No- but it happens? [tape flips.]909 910 Tom:And the light?David?s not going to produce it in the91 same way.912 Marc: No but he?s going to radiate it in the same way.913 Marc: Yeah.914 Tom: What?s the difference?915 Steve: Why916 Marc: One is generating?the other is, the other is? look. Let?s917 Tom: Well what are we?one is generating?918 Marc: Let?s talk radia? let?s talk energy. Let?s not talk heat or919 light. The sun is generating energy. How does that920 energy travel? IT travels in a vacuum. Why can?t the921 energy? David IS generating energy. He?s generating92 energy because his molecules ? it?s a different form923 Steve: Only if he?s absorbing the energy.924 Marc: That?s right?he absorbs it925 Steve: That?s an assumption we?re making.926 Marc: Right, but I?m saying he absorbs it. We know the earth927 absorbs it, we know the moon absorbs it. We know that928 molecules in a vacuum absorb energy that?s being thrown929 at them. That?s how the atmosphere heats up that?s how930 the earth heats up?931 Steve: So only if??932 Leslie: So let?s say David?s green. [Ok ok David?s green.] What93 does that mean. Let?s assume it.934 Steve: So he?s absorbs he?s absorbing green935 Marc: He?s reflecting green936 Steve: Oh reflecting green and absorbing everything else.937 Leslie: Everything else- ok. so now this this is just easier to talk938 about?there?s the green light that?s reflected we don?t939 have to worry about that anymore. What happens to all940 the other light that he?s absorbing?941 Marc: It?s absorbed by David.942 Leslie: And then what? He just keeps heating up each time more943 comes in?94 Vic: Ok here?s the thing?945 Marc: You chose a stable color?green is a manifestation of946 stable energy. He is green degrees warm. Right?947 Vic: Huh?948 Marc: He will only be green degrees warm.949 260 Leslie: [Points to a green shoe.] Is his shoe green degrees warm?950 The sole of Cameron?s shoe?951 Marc: It?s a metaphor?it?s a metaphor?they?re always green.952 Tom: It?s the same temperature as the rug (in the room).953 Marc: Well you know what it?s probably not the same954 temperature have you ever had a black surface and a95 white surface? The black surface is hotter than the white.956 Steve: Only?.957 [Laughter.]958 Amelia: Black cars are hotter than white cars?that?s why people959 who live in deserts drive white cars.960 Tom: We?re talking about things in an atmosphere. We?re also961 talking about black which absorbs other forms of energy.962 Marc: Yeah- but the analogy, you can see the963 analogy?different colors.964 Tom: I can?t?black, black is like all of the colors, white is965 none of the colors.96 Marc: Ok so green is some of the colors so I can imagine that967 green would be warmer than white.968 [More about colors.]969 970 Leslie: The question about green was to differentiate between971 reflected light, transmitted light, created light, the green972 that we see from David is reflected light ? it never973 did?David never had to worry about it. He just threw it974 away as soon as it came. The rest of the light gets in975 somehow and is no longer visible [right]. Ok.976 Vic: It can not be being reflected.97 Leslie: Right?and if it?s absorbed?for a car, does that make it978 hotter?979 Tom, Vic: Sure, yeah.980 Leslie: Ok?so it?s going to make David hotter.981 Marc: Yeah.982 Leslie: Okay.983 Tom: But it has to go somewhere because David does not984 Katie: heat985 up indefinitely986 Tom:987 does not heat up indefinitely unless you [?]98 Marc: But it goes in the form of green light! That?s where it989 goes!90 Leslie: No?we?ve already taken care of the green light?it?s not91 like he gets brighter as he heats up, it?s still just plain92 old?93 261 Tom: And the light is traveling?there are all these different94 frequencies of light coming at David.95 Marc: That?s right.96 Tom: So where.97 Steve: So every light ? he?s heating up with ROY BIV and98 giving away green, right? So he?s accumulating ROY99 and BIV.100 Marc: Right. Ok101 Steve: And he?s accumulating it and accumulating it and102 accumulating it103 Tom: He has to get rid of it some way we just don?t know.104 Vic: So at some point does David become?105 Marc: No but he gives it away in other forms of energy?heat-106 well infrared? Infrared primarily.107 Vic: Wait wait wait you cant you can?t you can?t change ROY108 to infra-ROY.109 Marc: Of course?(pauses)1010 Vic: You can?t you can?t give you can?t change ROY into101 infra-ROY1012 Marc: Well why not?1013 Vic: How does he do it!?1014 Marc: Because it?s ju- because as the rock absorbs the energy1015 the waves slow down ? it?s my frequency? it?s this1016 [does the motion, hitting thing]?the rock absorbs the ba-1017 ba-ba-ba-ba and it absorbs some of it so now it?s just?it1018 isn?t visible anymore our eyes just aren?t able?if you1019 wear infrared goggles.1020 Vic: I?m sorry I think the problem is that?that in addition to1021 ROY and BIV, we?re already assuming ultraviolet and102 infrared, and let?s say that he gives away all those things,1023 too, in addition to green. So he?s gotten rid of all of the1024 infra and all of the ultra and all of the gamma1025 Marc: And you?re asking me where does it go? It goes in the1026 form of that?you can?t dismiss that!1027 Vic: I?m NOT dismissing that! At all ? what I?m1028 suggesting is that we still have ROY and BIV that we-1029 that he?s not changing it into something else?1030 Marc: But he is?1031 [Voices.]1032 Leslie: Can you come up with another way of explaining ? I?I103 see the discrepancy, and I don?t think you understand the1034 discrepancy and I?m wondering if there?s a way you1035 might explain the discrepancy better?I have analogy I1036 can use ?1037 262 Vic: Wait wait wait?every?everybody is payin? me money.1038 Everybody is paying me money in different forms?in1039 dollars, five dollar bills, twenty dollar bills. [ok] I?m1040 savin? all of my 1 dollar bills that I give away?I do not1041 spend any of my dollar bills on anything ever. Which1042 means that I am gradually accumulating 1 dollar1043 bills?even if I?m spending it in 5s and 10s and 20s. so104 what do I do when I end up with 1000 dollars in one1045 dollar bills that I don?t know what to do with?!1046 Marc: I?m gonna change that analogy?or I could keep it I1047 could keep it! Ok? I?ll keep it fine?you know what I?m1048 gonna do with those one dollar bills? [tell me]1049 Well?those dollar bills become? you you spend 501050 cents of it in terms of heat and you throw the other 501051 cents of it away but we can?t see those 50 cents because1052 we?re only attuned?1053 Tom: You?re losing the analogy.1054 Leslie: The question is: how did that dollar turn into 50 cents. If105 the only thing you can throw away is coins, what1056 happened to the dollar bills.1057 Vic: I didn?t cut them into the shape of coins and pass them1058 out?I still have I have 1 dollar bills that I cannot break, I1059 cannot change at the bank because there?s no freakin?1060 bank.1061 Marc: But I?ll tell you what happens. If you really were [?1062 [mocking: I?ll tell you what happens?] if you really really1063 really were ??if you (someone enters and we applaud)1064 you?d be drownin? in one dollar bills.1065 Vic: This is our point!106 Marc: But my point is that you can?t stop converting those 11067 dollar bills to 50 cents! By the virtue of your existence it1068 means you must be (?)1069 Amelia: What happened to exploding in space?1070 Marc: What no no no?o1071 Vic: Our question fundamentally is?is?how in what way did1072 I change my dollars to 50 cents.1073 Marc: I?ll tell you ?1074 Then I interject, Steve notes that it isn?t fun to ?make stuff up? anymore and it feels like an argument and not a discussion. We take a break and don?t resume. 263 Appendix G Transcript 7 The fifth grade classroom in this transcript has been working with solar ovens over a series of weeks. In this transcript, they are discussing the relationship between light and heat. Student: That you can only heat so it travels that you can?t see1 traveling because it travels and then it attracts the to black2 and it would catch to black it would like to stay onto3 black I guess because it's black. (Students giggling)4 Student: I think I think I disagree with what I believe in that uh the5 light was exactly the uh?6 Teacher: So you disagree from what you said earlier, you mean?7 Student: Yeah.8 Teacher: Okay.9 David: because um I I think that the air is like heat because like a10 heater uses the air, it heats it up and the air travels around1 the house to heat up the whole house.12 Student: I dis13 Teacher: And how is that different from what you said before?14 David: Because I said that the heat is like15 Wasolla: I disagree with David because16 Teacher: By the way David, I think that so cool that that you17 thought something else and your ideas changed and you18 were able to express that. That's really ? that's19 neat?that that I like the way you?re thinking.20 Wasolla: I disagree with David what he said about air being heat.21 Because air can sometimes be cold.2 Student: But23 Student:No but24 Student: Yeah but heater?we have a heater25 Student: Not but that26 Student: Heater, we have a heater27 Student: That?s that?s28 Student: We have a heater thing in our house and you can turn up29 the temperature.30 Student: Yeah, that?s what everybody has31 Student: I. I didn?t say that.32 Teacher: Let?s listen to David one more time, Listen up.3 David: Wasolla, I didn?t say that the air is not?is always hot. I34 just said air is hot sometimes, so it could turn cold.35 264 Teacher: What made you change your idea?36 David: Because I thought of uh my dad working on the heater.37 Because my dad does heat. Heaters and air38 conditioners?and then I thought of the word in from the39 air conditioner?air? And then I thought that if air can be40 cold from an air conditioner, then why can?t a heater use41 air to make it hot?42 Teacher: Well the heater uses air and air is what makes the heat?43 David: Yeah.4 Student: I thought is was always gas.45 David: Yeah, because there?s like vents everywhere.46 Teacher:So what do you think it is in the air that is making heat?47 Student: Hmmm.48 David: I think it is the light. I think the light is like heating the49 air up.50 Student: I always thought it was like a gas or fire or something.51 Teacher: What?52 Student: The heat53 Teacher: The heat, the gas or the fire?54 Student: Yeah, not the light because if you have the dryer my5 mom always tells me to keep stuff away from the dryer56 because fire goes through there and it might catch on fire57 or something.58 Teacher: Hmmm.59 Brian: When I was up in New England, on our big ski trip thing,60 um I slept um on the floor ?cuz there were only two61 bedrooms. And I was right near the heater and my mom62 told me not to put anything near it or like it was an63 electric heater down on the bottom and my mom told me64 not to put anything near it or inside of the because it?ll65 catch on fire.6 Teacher:Hmmm67 Student: If you put paper near it, you know it can like burn it.68 Teacher: Ok, so there's something going on that can do that. Um,69 let's get back to let's let's continue where we?re going70 with this idea of light and heat and how heat is created71 and so forth. I like what you what you're thinking.72 Student: I think that light, this is um I'm kind of changing my73 mind, I think light is kind of light a comet it's going so74 fast like is burning up into heat it's like going so fast it's75 turning into heat. So when by the time it gets down to76 earth its heat and you sometimes it's heat and not um7 Teacher: What is that what you're saying?78 Student: I think that?s kind of like what Seong is saying.79 Teacher: kinda like what Seong was saying, yeah.80 265 Student:[Unclear.]81 Teacher: How many people think that you get the heat when light82 hits something, like causes heat.83 Student: I do. I do. Me. I do. [Students mumbling].84 Teacher:What do you think? Why do you think that?85 Lisa: I think that sometimes, well, most of the times, light is86 not always containing heat. Like, like this light up here,87 it?s not con?it?s not, its not ?8 Dashawn:Burning?89 Lisa: Yeah, like making you hot.90 Kyle: Yeah it?s not making anything hot.91 Anna: But it's just?what if you go up there and touch it? It92 would??93 Brian: That's because your finger is an object. When it hits94 something it?s hot.95 Teacher:Oh, I see. So you get, there's a reaction when you touch96 light.97 Brian: But it's also a question like, um, if a door slams? if a98 locker door slams and no one?s around to hear it, does it9 make a noise? Because you don't know if? if you don't10 touch it and the light is making heat and making the air101 hot. You won't know.102 David: Yeah well how is, fine then put it this way how does the103 fire makes you hot when you're not touching it?104 Brian: Because it's warm!105 Student: Because that's a fire.106 David: But it's still, it's the light source.107 Student: Heat heat.108 Brian: But when you say a lightbulb, a lightbulb doesn't really109 run on fire. It runs on electricity.10 David: I know! I thought it [?] but it?s still a light source.11 Student: I?its because its wood. Wood catches on fire like paper12 so when you eh?wood?if woods are made out of tree13 trunks.14 Student: Woods? Woods?15 Student: Wood. [?] Tree trunks16 Teacher: Like a piece of wood.17 Student: Yeah, um, it?s made into paper sometimes, and when you18 put that together with like newspaper and you light it, um19 it forms a fire.120 Teacher: So anytime you have light, do you have heat?121 Student: Yeah.12 Student: Sometimes.123 Student: Not always, not always.124 266 Student: I?I have a lightbulb and it gets really hot because when I125 when I put it inside a diff..because it?s a different kind of126 light bulb so it gets really hot and that?s not what usually127 lightbulbs do. They just get not hot its just..128 Student: There?s different light bulbs for different purposes129 though.130 Student: I think?. Like outside its its light its light outside but its131 still cold outside, so light doesn?t always get hot, get you132 heat.13 David: Yeah but that that is could be like the angle that the earth134 is at. You could you never you could always think of135 that.136 Brian: Remember when we learned about137 Student: Yeah but it?s the light is not um solar138 Brian: The light. I mean the sun and the earth139 Student: I kind of agree with [?]140 Brian: I don?t think it?s the angle. (Teacher: shh..) Remember141 when we learned about light. I mean, the sun, the earth,142 and the planets, its like, what the an..what angle the earth143 is at. And what angle the sun is at.14 Student: Well the sun doesn?t turn.145 Brian: What angle the earth is at.146 Student: And sometimes where the moon is.147 Student: We have the earth is rotating in the front.148 Student: Like rotating [?]?149 Student: No it's revolving150 Brian: Like right now we have winter and Asia, right now, or in151 China or (Student: California) over there over on the152 other side of the world, um they're having summer over153 there right now.154 Student: Like Australia15 Student: Yeah156 Students:[Mumbling.]157 Student: California?s not the other side of the world.158 Student: But they have different kinds of life over there at [?] And159 they do different things and have different colors.160 Student: They can last longer than the other [?]161 Student:No they don?t162 Teacher: So does it have to do with the angle of the lens?163 Student: Yeah, yes. I agree.164 Teacher: So when we set up our solar ovens do we have to put165 them at a certain angle in order to create heat?16 Student: Yes.167 267 Student: Remember when you were talking about light [?]? and168 you drew a diagram on the board and we had for our169 warm up?170 Student: Well maybe it would be different. I think the angle171 would be..dot the angle would be the light and the boxes172 right here then the um the foil and right here so it would173 hit the foil and then come inside the um solar ovens.174 Student: Because if it's if the light is facing the other way then175 there wouldn't be, it can't just go around over the foil and176 then hit it and then go back in.17 Teacher: Frankie and then Kyle178 Frankie:[?] I think it does have something to do with the angle179 because when we were doing that experiment with Miss180 Viglioti it um each angle got a different temperature like181 direct got the highest and then [?] and then the shadow.182 Student:[?]183 Kyle: It depends on how close on how close the heat is to the184 solar oven.185 Teacher: That's kind of similar to what Brian was saying, that it186 depends on how far the Earth is from the sun. [?] Ok, I187 notice that some of you are getting a little antsy.18 What?moving around a little bit. Um?let?s kind of189 back this up a little bit. Let?s wrap it up with any final190 thoughts about what we talked about today.191 David: Um..I remember somebody saying that the sun and like a192 light bulb has like different kin..ah..heat like different193 temperatures of heat. But I don't remember who it was.194 So ahh.. But I think that since the sun is so far far away195 from us like the lamp would be like close to the solar196 oven then like they?re around the same temperatures.197 Student: I thought that198 Student: The sun and the in so? and the light, the sun and our19 light bulb would be at the same temperature?20 Student: No, not really.201 David: Like um the sun's really powerful and it hits us, right?202 But it's not on its full capacity because it, the light travels203 all the way over here so if the light bulb is like weaker204 than the sun and it's closer to the uhh solar oven then I205 think that they would be around the same area of206 temperature.207 268 Appendix H Transcript 8 The following transcript is from a 5 th grade classroom. In a discussion about falling objects, the students were using the word ?gravity? to explain their reasoning. Curious about what the students were imagining gravity to be, the teacher asked ?what?s this word, gravity?? Teacher: What?s this word gravity? That?s another big word. We1 use that word a lot. What does gravity mean?2 Ibrahim: Like, like if I throw this pencil up in the air, like it pulls it3 down with strength.4 Teacher: So gravity is a pull?5 Ibrahim: Yeah.6 Student: No7 Ibrahim: If we didn?t have gravity, then?8 Teacher: Gravity is a pull downward.9 Ibrahim: Yeah10 Teacher: Pulls things down. [Several students start dropping1 pencils] Anybody want to?12 Student: It speeds up.13 Teacher:? agree with that or challenge that? Theodore.14 Theodore: Like um, gravity is like when you are like in space and15 um then like when you are trying to punch like um,16 somebody and your hand stops like that, because you go17 and go slow, first and second.18 Teacher: You go slow in space?19 Theodore: Yeah, you go slow in space.20 Teacher: Why do you go slow?21 Theodore: Because space like um, space has too much high gravity2 Teacher: Space has a high gravity.23 Theodore: Yeah. Which which lets you, you walk slow, you punch24 slow, or you can do everything slow.25 Teacher: Um, anybody else? Julie.26 Julie: Remember when he said, the last thing I remember is that27 you said that if you throw a marker in the air, it had the28 possibility of going down or the possibility of going up?29 Only that it would go up a little while then it would come30 back down.31 Teacher: What does that have to do about gravity?32 269 Julie: Huh?3 Teacher: Huh?34 Julie: That, it could (??)35 Teacher: Does gravity making it go up, or does gravity make it36 come down? What?s happening? Gravity making it go37 down. Okay. Uh, Thimios.38 Thimios: I have two things to say.39 Teacher: Okay40 Thimios: First of all, space has a low type of gravity.41 Teacher: Oh, so you are disagreeing with Theodore?42 Thimios: Yeah, because, right there [written on the board], it says43 gravity pulls downward. In space, it is like it just flies.4 And about like the circle thing, you can balance it. But it45 is like, it concentrates on the middle. (??) balance.46 Teacher: So you are saying if it, if it a sphere on a flat surface, it is47 easy to make it move.48 Thimios: Yeah, because it?s concentrated.49 Teacher: Because the gravity is in the center, the gravity is on the50 middle. But if it was on a curved surface, and it fit51 inside, then what would happen?52 Thimios: You would have to like pick it up and throw it.53 Teacher: It would be harder to make it move and roll. Okay54 Thimios: [??]5 Teacher: Theodore:56 Theodore: I disagree with Thimios.57 Students: [laughter]58 Theodore: I saw a movie, a movie where two people were talking59 about space, like um, like um, they look like, what?s the60 name again?61 Students: Astronauts62 Theodore: Yeah, astronauts. And um, they said that they had a63 really high gravity. Gravity, like um, like one day I64 watched a cartoon called Jackie Chan Adventures.65 [Students laugh]. Um, They showed when he was about6 to punch a man. And then his hand moved so slow um67 Teacher: He was in space?68 Theodore: Yeah, he was in space.69 Teacher: All right, we can talk about this. Let?s talk about space70 and gravity. We have two opinions. One, that space has a71 Ibrahim: low gravity72 Teacher: A low gravity, or a less gravity than Earth. And the other73 one is that er space has a lot of gravity. And Theodore74 says that space has a lot of gravity and that?s why75 everything moves so slow[ly]. Thimios says that space76 has a little bit of gravity and that?s why if you jump up,7 270 you would just keep going up and up and up. Right?78 [Thimios shakes his head yes and raises his hand] Let me79 hear someone else before besides these two then I will80 come back to these two. Okay. What do you guys think?81 Uh, Felix.82 Felix: Well, I think there is less gravity, be, if, if, you throw83 something in the air you know it?s going to come back84 down because gravity um, pushing it down.85 Teacher: Here on Earth?86 Felix: Yeah.87 Teacher: Uh, huh.8 Felix: And if we?re in space, there?s less gravity, we?d be flying89 up and jumping (??)90 Deena: I agree with Thimios just because well that that?s why if91 you threw a pen or anything in the air, it would fly down92 really fast because of the gravity. It has a high gravity93 here. And in er, in space, if you jump up, you would just94 like keep going up in the air because you have a low95 gravity.96 Santiago: Uh, I kind of agree with Theodore because like the sun it97 has like enough gravity to keep us from spinning around98 in orbit.9 Teacher: So gravity comes from the sun?10 Santiago: I think, I don?t know.101 Teacher: Well, why do you think gravity, lets, why do think102 gravity comes from the sun?103 Santiago: Because it, keeps other planets from rotating around it.104 Teacher: Okay, so because planets rotate around the sun, then105 gravity must be, the pull must come from the sun.106 Because it [the sun] stays still and the other planets are107 moving? That?s your theory?108 Santiago: I don?t know.109 Teacher: Fine. Okay. Lorenza10 Lorenza: I have to agree with all of them, because like11 Teacher: Even, both of them?12 Lorenza: Yeah.13 Teacher: Okay.14 Lorenza: When you walk, you walk slow, but you can talk slow,15 jump and just stay.16 Teacher: Here, on Earth?17 Lorenza: No, in space18 Teacher: Oh. So, that supports what theory? That there is a lot of19 gravity or a little bit of gravity?120 Lorenza: Like, like half.121 Teacher: Half? Oh, so not a little bit, not a lot but some.12 271 Lorenza: Yeah123 Teacher: Julie.124 Julie: I agree with, um, (??) if you go up and jump up?125 Teacher: That means a lot of gravity or a little bit of gravity?126 Julie: Um, a little bit of gravity.127 Teacher: Okay.128 Julie: Um, if you go up and (??) up and down, that (??) there is129 still(??)130 Ibrahim: I agree, I disagree with Theo because um, when you?re131 going in space and jump on the moon, you jump back up132 you stay um, um in space you don?t move anywhere, you13 don?t come down. But on Earth, if you try to jump, you134 come straight falling back down, so I think um, space has135 a lower gravity, and and Earth has a higher gravity.136 Teacher: Okay. Cristian.137 Cristian: Um, I agree with Theodore because, um, like, gravity138 makes you slow. Um and (??) in space walking like slow139 and like to the space shuttle, you have to walk slow, and140 like, it?s like (??) it feels like you need to be so strong, it141 feels like it is hard to walk or something.142 Teacher: So what does that mean?143 Cristian: That it has to like be strong to walk?14 Teacher: So you agree with Theodore.145 Cristian: Um, huh146 Teacher: Okay, Khawar.147 Khawar: I think in space there is a low center of gravity because148 like149 Teacher: Low center of gravity?150 Khawar: Well, like less gravity (??) In space when you go up, you151 stay up, but um in Earth, there is more gravity like152 because when you jump up, the gravity pulls you down153 fast, so I agree with him.154 Ibrahim: Um like I think um like um Santiago is right when like he15 said the sun like has it pull the earth and the planets156 together. But like if you?re, um, um I think that he was157 right because how come the Earth is not moving away158 from the sun.159 Teacher: So because the Earth is not moving away from the sun,160 you say that the gravity is coming from the sun.161 Ibrahim: Um hum162 Teacher: Okay, ahh. Who did I say was going to be next?163 Lorenza.164 Lorenza: Um, I was going to say that um, I kind of, um I still kind165 of agree with him, but um, but um (??) said, but um, but16 272 um that when we go up in the air (??) I think that we just167 will come down slowly.168 Teacher: You think that he will come down eventually.169 Lorenza: Yeah.170 Teacher: But, it just takes a longer time. But does that mean more171 gravity in space or less gravity?172 Lorenza: I am not really sure.173 Teacher: Don?t know, okay. Thimios.174 Thimios: Can I do a demonstration?175 Teacher: Sure176 Thimios: If gravity is pulling down, right.17 Teacher: Um, hmmm178 Thimios: So if you were doing (??) punching going like that, it179 would just [he makes a slow motion downward punching180 movement] it would go to the floor.181 Teacher: Where?182 Thimios: In space because its, because gravity going downward.183 Teacher: Uh, huh184 Thimios: So it?s like that. When you try to punch (??) and because185 you?re going so slow, it?s because when you go to space.186 It?s because your weight is divided by three. So it makes187 you weaker, kind of.18 Teacher: So I would weigh one third less in space, or one third189 more?190 Thimios: One third less.191 Teacher: That?s a good diet. Let?s go to space. [laughter] Okay,192 Kevin.193 Kevin: I agree with Theodore, because um, when I was watching194 this cartoon, when the gravity went up, when they were195 playing, it was harder for them to to move faster.196 Teacher: Okay. So. Because it was harder for them to move, you197 think more gravity. That gravity makes it harder for you198 to move. Okay, ahh, lets have Deena.19 Deena: I now agree with Theodore.20 Teacher: You changed your mind?201 Deena: Well, cause look it?s, it?s like, this has low gravity, (??)202 never mind, never mind203 Teacher: Go ahead204 Deena: No, never mind.205 Teacher: Okay, Kenny.206 Kenny: I agree with Theodore because um, um sometimes in207 space, um you weigh lesser than you would, so if it?s like208 um, it?s like as if you um were on a bungee string or209 something like that, and it?s like the moon or something.210 Teacher: What about the bungee string, moon?21 273 Kenny: It makes you like go, it?s like um it makes you jump212 higher, but213 Teacher: What?s it? What makes you jump higher?214 Kenny: The bungee thing or whatever.215 Teacher: You would jump higher in space or on earth?216 Kenny: Space.217 Teacher: Because--?218 Kenny: Because you going to weigh less. And when you jump219 it?s like you?re going to have times three of what you20 would jump here.21 Teacher: Okay, um Felix.22 Felix: I agree with Theodore and Thimios, because there is just23 a little gravity in space. And if you um, If you went up in24 the air, you uh would eventually come down because, um25 there?s a little gravity in space.26 Teacher: So just a tiny bit, but not as much as here?27 Felix: Yeah.28 Teacher: Uh, Santiago.29 Santiago: Uh (??) you said like that the sun or something like that230 the gravity pulled in a like a comet, or asteroid (??)231 Teacher: Okay232 Santiago: [??]23 Teacher: So what are you saying about where gravity comes from?234 Santiago: (??)235 Teacher: You still don?t know? But somewhere there?s gravity236 pulling some things in space closer to earth, like asteroids237 and comets and stuff.238 Santiago: Yeah, and like the moon239 Teacher: The moon240 Santiago: Yeah, it like (??) it controls like (??) the waves and so241 that makes like tidal waves, so that means the moon has242 gravity.243 Teacher: So the moon has gravity and that causes waves and tidal24 waves.245 Santiago: I think.246 Teacher: Okay, Julie?247 Julie: Um, I think um that in space, um, when you try to turn248 around in space, it takes a little long, and that?s what249 happens to the Earth when it tries to rotate, that;s why it250 takes twenty-four hours, it takes a day to rotate one whole251 turn and maybe um maybe there?s um that?s why (??) the252 earth has low gravity in the air.253 Teacher: A little gravity254 Student: Low gravity25 Teacher: Low gravity or high gravity256 274 Julie: Um, low gravity.257 Teacher: Theodore thinks there?s high gravity.258 Julie: Then I agree with Thimios.259 Teacher: You?re agreeing with Thimios. Okay, ahh, Khawar.260 Khawar: You know what Kenny said, he said like he said that you261 could loose weight when you go to space and um that?s262 what he (used or knew). And he said that he agreed with263 Theodore like when you use something, that Thimios (?)264 Teacher: All right, Thimios.265 Thimios: I just want to say something. Cartoons are cartoons.26 They are not real life, okay people.267 Santiago: What do you mean they are not real life?268 Thimios: Gravity is the a pull downward. (??) They?re saying269 gravity, they?re saying gravity is a pull upward! It is a270 pull downwards. Those comics are wrong. They?re lying271 because there is not a lot of gravity. So they are going up272 and space and they are not falling down. Because there is273 no gravity there.274 Theodore: I disagree with Thimios.275 Students: [a lot of laughter and noise]276 Teacher: I can?t hear. Go ahead Theodore.27 Theodore: I saw a movie, ?The Matrix? and how come they do that278 stuff and um279 Students: It?s a movie! (??) Shh!280 Teacher: Lorenza281 Lorenza: I tend to disagree with Theodore because they could be282 using a harness and pulling on wires.283 Teacher: You have seen them do stuff like that in a movie before284 with a harness?285 Lorenza: Yeah.286 Teacher: Deena.287 Deena: I kind of agree with both of them, it?s because like when I28 go in the water it?s like I can carry like when I go into the289 water, it?s like you loose a little weight cause like my290 little sister like her, she really can?t pick me up because I291 am really heavy and when I am in the water, she can pick292 me up.293 Teacher: So what does that say about gravity?294 Deena: I don?t know, it?s like. I don?t know.295 Teacher: Are you connecting? Does anyone know why she said296 that? Rebecca.297 Rebecca: Um, I think she saying this because, like if you are in the298 water, you are still staying down in the ground, but once29 you are in the water you feel like you are loosing gravity30 of yourself.301 275 Teacher: And what did you say?302 Rebecca: [??]303 Teacher: So being in water is like being in space? Why?304 Santiago: Because it is more easier to pick up a rock in the water305 and in space.306 Teacher: So, it is easy to pick up heavy things?307 Deontrae: No it?s easier to pick up heavy things in space.308 Students: (??) water makes it lighter, yeah.309 Teacher: So is being in water and being in space similar?310 Students: Yes. (??) No.31 Teacher: Ah, hah one at a time, one at a time. Julie.312 Julie: I think it is similar, um because um, water, you go into313 the water, you could um, you could kind of loose weight.314 You can push the water up.315 Teacher: Why do you say loose weight? Explain that to me.316 Julie: Because if you like um you?re not, you?re not like on317 Earth. On Earth you could just touch the water and pick318 it up like this in your hands, and then it will fall out319 though. But when you?re in the water, you can just push320 the water off you, it?s like, um heavy. It feels like you321 lost weight or something.32 Teacher: Okay, Santiago then Deena.323 Santiago: Like when you are in the swimming pool and like when324 you reach the bottom and then you can jump up high,325 from the bottom. That? kind of like space.326 Teacher: Why is that like space?327 Santiago: Ah, You can jump up high.328 Teacher: Because you can jump high. Ah. Deena.329 Deena: And it is kind of like what Thimios said. Because it?s30 like. That?s why it is really hard to walk on, that?s why is31 really hard to walk on water like on beaches. That?s why,32 it?s like sometimes it?s hard for me to walk on the water33 in beaches.34 Teacher: So, it?s hard for you to walk in the water like it?s hard for35 you to walk in space.36 Deena: Yeah, you have to, yeah, yeah.37 Teacher: Ibrahim.38 Ibrahim: I think water, um water, is the same as outer space39 because like when you are walking on the water, it?s like340 gravity is pulling your legs down.341 Deena: Yeah, it?s hard.342 Ibrahim: It?s like, when you?re walking like I went to um Ocean343 City, I went into the water, the water pulled me down.34 Teacher: Um hm. Okay, pulled you down like what?345 276 Ibrahim: Like, like gravity is pulling me down. And when I went346 to the sea, close to the sea, the water was pulling me347 down still, kind of.348 Teacher: Thimios.349 Thimios: The water, I think it has like a medium center of gravity,350 because in the water you gain weight. You know,351 because it is harder to move and everything.352 Teacher: So some people, so you are disagreeing with the people353 who say you loose weight. You say in water you are354 actually heavier?35 Thimios: Yeah, because you have to, because you have to like if356 you try to walk in the water, you walk like this [he takes357 steps with a long stride].358 Teacher: Like slow motion?359 Deena: Yeah, it?s hard.360 Teacher: Okay361 Student: And (??)362 Thimios:And, you know, it?s hard to pick up things in the water.363 Deena: Actually, it not. Actually, it?s not. It?s light. It?s really364 light.365 Thimios: Well, if you tried to pick up like a big, big rock,36 Deena: It?s light.367 Deontrea: It?s light368 Students: (??)It?s real, real light. You could pick it up easily, with369 your hands.370 Thimios: But then it wouldn?t weigh so much. But in the water it371 gains weight.372 Deena: Actually, it doesn?t373 Kenny: No it doesn?t. It looses weight.374 Students: (??) [Many students talk at once.] I know.375 Thimios: Water has pressure. Water has pressure. Remember the376 Ranger Rick magazine we read? It said (??)37 Student: Shh.378 Thimios: Water pressure makes it hard on you. So it?s like you379 have to like use all of your muscles to [many students380 start to talk]381 Teacher: So you are saying because of the water pressure, the382 water has pressure, which makes it hard for you to walk.383 Thimios: Yeah.384 Teacher: Okay, ah. Felix.385 Felix: Ah, ah, I think that uh space and water, kind of similar386 because except space you would jump up in the air and if387 you?re down in the water sometimes, you would, um float38 back up if you are um, I don?t know.389 Student: Oooh!390 277 Lorenza: Um, I kind of agree and disagree with Thimios because391 like it?s like the rock (??) right, but it would be hard to392 pick it up because the rock, the water gives a lot of393 pressure on the rock. So394 Teacher: What do you mean the rock looses weight. Explain that?395 Lorenza: Like, it is kind of like it is lighter, below the water, like396 when you go to pick it up. It won?t come up because the397 water gives a lot of pressure on it. (???????)398 Teacher: Khawar. Julie39 Julie: The reason why the rock in the water because Earth,40 when throw it on the ground, it will, um, land easier401 because of the gravity, but when you throw it on the402 water, it takes longer for the rock to go down to the403 surface. Because how, how, how heavy the water is and404 how much pressure it is on it. And because the rock is405 also heavy. And that the weight of the water, it can just406 push it down. (??) But on Earth the air is pushing it down407 and the air doesn?t weigh anything, so it will just push it408 down to the ground.409 Teacher: So the rock is pushing So you are saying that the rock410 moves slower in water not because of gravity, but41 because of the water pressure? Is that what you are412 saying?413 Julie: Um hmm.414 Teacher: Okay, so you are saying that the air doesn?t have a lot of415 pressure so the rock falls quickly. Santiago.416 Santiago: It?s not really like you are getting heavier, because all of417 the water around you is making you harder to move418 Teacher: So you are not gaining weight.419 Santiago: No420 Teacher: Uh, Ibrahim, Thimios and Theodore.421 Ibrahim: I agree with Lorenza like earlier what she said because42 she said um, like um, um like. When you?re in space you423 fall down um like it takes a long time to fall down. So424 like, if you drop something in the water, it?ll try, it floats425 up slowly. So I think water, and um outer space is426 similar.427 Thimios: Can I do a demonstration?428 Students:Uhh!429 Thimios: Pretend you are a little green person with a little tiny430 body. Everybody is saying that gravity is here or that431 Earth has a lot of gravity (??) or gravity is coming down432 to you. It would be harder to pick something up in the43 water because gravity is pulling you down here, like that.434 278 Teacher: So you are saying not only do you have to pick up the435 rock, but you have to fight gravity pulling the rock the436 down.437 Thimios: Or pulling the rock up438 Teacher: Gravity pulls the rock up?439 Thimios: No, gravity pulls you down but40 Deontrae: Gravity does pull the rock up.41 Thimios: That?s why the rock will be weighing more. The people42 will be weighing more because, gravity is pulling down43 the rock.44 Teacher: Okay45 Thimios: That?s what everybody is saying (??)46 Teacher: Do you agree with that or disagree with that?47 Thimios: I agree that the gravity is pulling you down. That?s the48 only thing I agree with these people.49 Teacher: Okay, Theodore.450 Felix: I?m confused.451 Teacher: Oh well, Thimios is saying that when you try to pick up a452 rock, gravity is pulling the rock down, and you?re trying453 to push it up. That?s why it?s hard. Because you have to454 fight against the weight of the rock and gravity. Yes?45 Thimios is shaking his head yes. Theodore.456 Theodore: Thimios said that the rock that the water makes457 something heavier. How come like when we put a beach458 ball in the pool, and so, and and then we push it down and459 Teacher:It goes under the water.460 Student: Shh461 Deena: Yeah!462 Theodore: It pops up really hard and um it may hit your face like463 pow!464 Teacher: So, it pops up with a great force?465 Felix: Yeah, it does!46 Thimios: It?s because it?s light. It doesn?t weigh anything.467 Theodore: Basketball too!468 Deena: It has air inside.469 Thimios: A basketball only weighs four pounds. (??)470 Theodore: Four pounds is heavy!471 Felix: Ohh!472 Thimios: [??] only weighs five pounds. It?s going to jump up and473 gravity is going to pull it down when it is in the air.474 279 Appendix I Transcript 9 This transcript is from a second grade classroom. The teacher has brought magnets and is asking the students how do magnets ?work?? One question related to this is concerning the ability of a paper clip that is touching a magnet to then pick up another paper clip. The transcript begins with a discussion regarding this. Dalton: Well if it?s third (the paper clip) then, um, it would1 definitely pick the whole thing up.2 Teacher: Why?3 Dalton: Because um it?s um takes a lot of um it would take about4 two magnets to get put together to get- hold a rock up.5 Hold a rock. And put two paper clips on? and he said6 he put it third and then he put the paper clip on the7 bottom and then picked it up and um um it can?t get very8 much magnetism through it because it?s just two little9 small paper clips.10 Teacher: Okay, so you?re, are you saying there?s not enough power1 in one of these?12 Dalton: There?s enough, um, electric power in it but um it just13 couldn?t hold up the rock because it doesn?t take very14 much.15 Teacher: Okay.16 Dalton: It doesn?t, ?cause, um, because um the power the magnet17 takes a little bit of power through each paper clip and um,18 it goes right down into it. And um, the rock?s heavier19 than it so it would have to fall off.20 Teacher: Okay so you?re saying that what Calvin described can?t21 happen because the rock is too heavy?2 Dalton: Yes.23 Teacher: But you also said that some of the power or whatever24 goes through the paper clips?is that true?25 Dalton: Yeah but um if you?ve got a rock, it?s hard to put26 a rock on because some rocks aren?t made of metal.27 Teacher: Okay, Calvin do you want to??28 Calvin: Um? well, when I pulled it up I held it from the magnet29 and the rock so it wouldn?t fall down.30 Teacher: Oh, so you were holding.31 Calvin: The second time when I hold the rock.32 Teacher: Because the first time what happened?3 280 Calvin: Yeah, because the first time all I did was pick the magnet34 up and it went fweep!35 Teacher: Okay. So when you did the experiment again you held36 the magnet here with the paper clip and then you held this37 rock and there were two paper clips hanging off the38 bottom of the rock and that worked?the paper clips hung39 off of the rock. Okay, what do you think about that,40 Dalton?41 Dalton: Um it would only be possible if um you got the magnet42 and you stuck the rock on first.43 Teacher: Why?4 Dalton: Because the magnets are smaller than the rock and it, the45 rock takes more power into it so you can put three paper46 clips onto the bottom and pull it up without it dropping.47 Teacher: Okay so does the rock pull something away from the48 magnet?49 Dalton: Kind of.50 Teacher: Kind of. Okay. Renee.51 Renee: I think there is clay inside of it because clay does pick52 stuff?things, like paper and stuff.53 Teacher: Okay, so if there?s clay inside here, does that help it stick54 to things? That helps the magnet stick? Okay, does it5 stick to paper, like clay does?56 Renee: Ummmm.57 Teacher: Okay, so the clay that?s in here that you?re saying is in58 here- what does it help the magnet stick to?59 Renee: Metal.60 Teacher: Okay. So is it?? Why does that work? Because if I61 have clay and I can stick it to paper, but I can?t do that62 with this?63 Renee: I mean if the clay was like [?] it could stick to paper64 [Teacher: Okay okay.] And something that?s metal then it65 can only stick to metal.6 Teacher: Okay. Alright. Go ahead Taylor.67 Taylor: Um I have a different one. Yesterday when we were at68 the science Saturday we saw a reaction when this guy69 poured an um really cold water and then he put food70 coloring in it and he um, added? I forget what it was71 called, but when it put it in it got all bubbly?72 Teacher: Very cool, very cool. Kind of different from magnets,73 huh? Okay. Alright. How about over here at this table?74 Do you guys have anything you want to add to this power75 idea? Go ahead Evan.76 281 Evan: I agree with Taylor about the little magnets inside the big7 magnet. Because, um, a couple little magnets can stick to78 anything.79 Teacher: Okay, so you?re ? you?re saying there are little magnets80 in here and if there?s a couple of them in here that?s going81 to make this stick?82 Evan: To most anything.83 Teacher: To mostly anything, okay. So ? where is this power stuff84 coming from? Go ahead Carla. Oh I?m sorry is there85 something else you wanted to say?86 Dalton: I don?t understand!87 Teacher: So don?t I!?go ahead?8 Dalton: Because Evan said um well?I was thinking in my head89 when he said that there?s magnets inside there?what are90 in the other?what are in the magnets that are inside the91 big magnet?92 Evan: Ohhh.93 Teacher: OOOH! Uh oh! [laughter] [talking] Let me ? let me94 make sure I?m understanding Dalton correctly?let?s put95 this back out on the floor here?hang on, hang on for a96 second here. Evan says there are little magnets in here97 and you were agreeing with Taylor- right? And Dalton?s98 question is: Okay, well if there are little magnets in here9 making this work, then what?s inside the little magnets?10 Okay?that?s what he wants to know [so do I!], that?s his101 question to you Evan.102 Evan: Little pieces of metal.103 Teacher: Little pieces of metal?104 Dalton: Then what?s inside them?105 Student: Yeah- what?s inside the little pieces of metal?106 Taylor: Clay.107 Teacher: Oh Taylor has an answer, she says clay.108 Student: Clay?!109 Student: And what?s inside of clay? Play-doh!10 [Laughter.]11 Teacher: Now wait a minute, wait a minute, we?ve got this magnet12 and we?re breaking it down into smaller and smaller13 pieces, but then how does that make it work?if that?s14 really what in here, we work our way back and way say15 okay: clay, bits of metal, little magnets, big magnet: how16 does that make this magnet work?? I don?t know!? Ben?17 Ben: I disagree with Evan because last time (??) a piece fell off18 and there wasn?t any little pieces inside.19 Teacher: Oooohh?. At the very end of class last time I was120 talking to some folks over here and we took two of these121 282 and they went?fwwp- they smashed into each other and12 a piece broke off and Ben is saying he saw that and he123 says there wasn?t a little magnet inside. Hm. What are124 you thinking Taylor?125 Taylor: Because it was just blended in with that magnet126 because most of them are in the same color.127 Teacher: Oh, so when this broke off?128 Taylor: There (?) the little pieces.129 Dalton: Then how could they- then how could they be so close130 together that you couldn?t even see the lines in between131 them?132 Taylor: Because they were glued.13 Dalton: Well glue makes ?em fatter.134 Taylor: There was clay on top of em135 Student: Nuh uh clay?s ?136 Dalton: Nuh uh clay?s not that black!137 Teacher: Hang on?[Savannah: There?s food coloring.]138 Savannah?s ? with food coloring. Okay.139 Dalton: Food coloring!140 Student: That would be [unclear: very weird?]141 Teacher: Hang on for a second?Savannah.142 Savannah: You had um if there were magnets inside the ? those143 magnets it would be really fat! It would be fatter because14 the little magnets are as thick as that.145 Teacher: Okay so you?re saying this is too thin to have little146 magnets in it?if this really had little magnets in it it147 would be fatter? This way? Okay [nuh uh]148 okay?Calvin.149 Calvin: I disagree with Taylor and because well I think that150 there?s um. That there?s um just the magnet the magnet151 is just there. You know? No other magnets.152 Teacher: So there?s there?s This is it?it?s a magnet, there?s153 nothing inside except ?magnet??the, whatever this is?154 Calvin: And the electricity?s in the magnet.15 Teacher: And the electricity. Alright- let?s get back. Wait a156 minute, hang on for a second?hang on for a second.157 Remind me about the electricity. I?m going to come back158 to that?yes?159 Student: I am confused with Taylor.160 Teacher: About what? Be specific what are you confused about.161 Student: What she said before um Calvin was talking?162 Teacher: You mean about the clay inside?163 Student: Yes.164 Teacher: Okay?do you want to add on to that?165 Taylor: Um?I don?t know what she?s talking about.16 283 Teacher: Okay. Hang on?let?s see if we can figure this out. I?ve167 got hands over here going off too. Emily?168 Emily: I have a question [go for it] um um what is169 metal? If that?s metal ? what?s inside it?170 Teacher: There?s a question: if this is metal then what?s inside.171 What?s inside?anybody have any ideas? Ben?172 Ben: The um what?s inside is like magnetite because173 magnetite made magnets so magnetite made magnets.174 Teacher: Is this made of magnetite? [mm hmm] What?s175 magnetite?176 Ben: A type of rock.17 Teacher: So this is a rock?178 Ben: No. It?s metal, because they made metal out of179 ?.different kinds of magnetite.180 Teacher: Okay, so this is metal, and metal?s made out of181 magnetite?okay alright. Who wants to add to that?182 Student: I agree with Ben because there?s rock inside it.183 Teacher: So there?s rock in here? This is metal and there?s rock184 inside? What do you think Emily?185 Emily: How do you know there?s rock inside?186 Teacher: Renee? How do you know? How do you know if there?s187 rock inside? [I have a question] Katie? Not sure?18 Dalton.189 Dalton: Um?there can?t, there could be some metal on rocks190 because um we have um a park (?) right off of our lane191 it?s inside and I like to pick rocks up and throw ?em and I192 saw some that had metal on the side of them.193 Teacher: Okay how does that relate to magnets?194 Dalton: Because magnet?it?s kind, because magnets are made195 out of metal and it had stuff kind of like metal.196 Teacher: Okay so the rocks you found had something kind of like197 metal and that makes them kind of like magnets?198 Dalton: Yeah?it had the same kind that they use for magnets.19 Teacher: Okay?Michaela?20 Michaela: How do you know there?s [?] metal inside?201 Teacher: I dunno?that?s a question for you guys?how do you202 know there?s metal inside? She ? Michaela asked a203 question, how do we know what?s in here? Yeah?Emily204 how do we know there?s rocks in there. Who?s got some205 ideas? Carla?206 Carla: I think there?s metal in there because if there wasn?t207 metal in there it would it [?] metal around the outside and208 it probably wouldn?t pick up metal that well.209 Teacher: So it has to be all metal or it wouldn?t stick?210 Carla: Mostly metal.21 284 Teacher: Mostly metal. Okay.212 Student: I know there?s clay in it because I went on this website213 about magnets and it said that there?s clay inside.214 Teacher: Hm?okay. So, go ahead. Taylor.215 Taylor: I ? um agree with Ben because that?s a rock it?s just they216 shaped it into a rectangle.217 Teacher: Oh, okay! so can I go out on the playground and make it218 do the same thing that this does? [Students: No no no.]219 Dalton: I?m confused.20 Student: That?s a special kind of rock.21 Teacher: Okay so I have to find this special kind of rock and that22 will work like this does. How are you confused?23 Dalton: Because um I?m confused by how do they make the rocks24 square? They just get a machine and they push it flat and25 they push it sideways??26 Teacher: Can I toss Calvin?s idea back out here for a second for us27 to discuss?28 Student:I don?t even know what it was?29 Teacher:I do. He brought up electricity. He said this is a magnet230 it?s only a magnet there?s nothing in it except electricity.231 Calvin: Electricity and the magnet.232 Teacher: Electricity and the magnet. Alright, what?s electricity?23 Calvin: What I meant was whenever it attracts metal, we can?t234 see the electricity going to it?except we can feel it since235 it?s pulling.236 Teacher: So if I have two magnets or a paper clip and a magnet?237 Which one?238 Calvin: Either one.239 Teacher: Either one?I can feel something pull it. Okay and240 you?re saying it is electricity or it?s like electricity.241 Calvin: It is electricity that pulls them together.242 Teacher: It is electricity. Okay, so then my question is: what is243 electricity? Dalton?24 Dalton: [Pointing.] That?s electricity! The light!245 Teacher: That?s electricity?alright?is that what?s in here?246 What?s in here? What?s making this work?247 Dalton: It?s wires!?[Students: Huh? What? Wires]248 Teacher: Okay?hold on a second I think your classmates are249 asking you what do you mean by wires? [yeah]250 Dalton: Um they have?you know how they make machine?cut251 a wire, it shocks you when you touch it? And um I tried252 it with a light bulb in the bathroom. [laughter]253 Teacher: Okay?so you hooked a wire to a light bulb?254 Dalton: No, I touched it and it um shocked me.25 285 Teacher: Okay, what does that have to do with my magnet? Are256 there wires in here?257 Dalton: It?s kind of like it?they used wires to put it in that? why258 um some of them have little holes left from it?I?ve seen259 em.260 Teacher: Okay- so to get stuff into the magnets? [what stuff?] I261 don?t know that?s what I?m trying to figure out. Wait a262 minute?Dalton, finish your thought?263 Dalton: Um?it?s kind of like it takes the electricity from the264 wires and plugs it in and then there it?s a wire. A big265 long wire. And then they push a lever up and hit on and26 then um the electricity flows down from a big huge um?267 I?ve seen on tv?it has this big wall on the top and268 electricity comes down and it goes into the wire like this.269 And the magnet and then um it has um a certain kind of270 electricity.271 Teacher: Okay, so to make this magnet work somebody hooked it272 up to a wire pushed the on switch, stuff came down273 through the wire to the magnet [electricity] electricity274 did?and now the magnet works.275 Dalton: Mmm hmm. It?s kind of like that?it?s magnetism.276 Teacher: It?s kind of like that?you keep telling me that?it?s kind27 of like that.278 Dalton: Well it?s not kind of like um?electricity. It?s magnetism279 that flows down?280 Teacher: Okay, do I have to plug this in to a wire?281 Dalton: No?when you?re making it.282 Teacher: When I?m making it I have to plug it in. [yeah] and give283 it magnetism. [yeah] okay. who else has some thoughts284 on that process?Savannah?285 Savannah: I have two thoughts on that.286 Teacher: Okay?go ahead. Be nice.287 Savannah: Make up your mind already! Between it kind of has28 something?289 Dalton: That?s hard to do! [Okay.] It?s hard to do both at the290 same time!291 Teacher: Okay so Savannah what?s your question. Specifically292 what?s your question?what are you confused293 about?you?re saying make up your mind Dalton.294 Between what and what?295 Savannah: Kind of and it is. Or it isn?t.296 Teacher: Okay?so you?re saying? is your question to Dalton: IS297 this electricity or is it kind of like electricity? [Yeah.]298 Hang on?don?t answer yet?yes?29 286 Student: I remember that one time in this classroom you did?we30 had two magnets and we put them in front of a car [yeah301 and what happened] and then one side it would push the302 car away and one side would pull it together.303 Teacher: Oooh?so how?d that happen?304 Student: Electricity.305 Teacher: Electricity?okay. [?] When you said the other side306 pushed it away?one side pulled it towards the other side307 pushed it away. Okay?so what?s going on with that?308 Emily?309 Emily: Well I am kind of confused with what Dalton said.310 Teacher: Okay- can you specifically ask him?31 Emily:Make up your mind?it?s kind of the same what312 Savannah said, like, well, what what do you think in the313 magnet?because you?re saying two things. Magnetism314 or electricity? What?s in there?315 Dalton: I can?t figure it out?she?s asking me questions and I316 make um a good sentences up, so they? they complete!317 Then?that?s what Ms. McRae always tells us to do! Use318 complete sentences!319 287 Appendix J Transcript 10 ?? what teacher what grade? Teacher: Did you and your partner talk about what is happening1 when solar energy heats water? Or did you not get to that point?2 Student 1: We didn?t get to that point.3 Teacher: You didn?t? So, you all need more time. Brian?4 Brian: Me and my partner, we thought that um what Brianna5 said?ahh?disagreed with her, that when?6 Teacher: So you guys could have a debate back and forth?7 Brian: But, when water would hit the top of it and spread to the8 bottom, send to put the thermometer at the bottom so it9 take the temperature at the bottom so that would have to10 be the temperature of the whole?of the water.1 Teacher: Interesting. Okay. That?s interesting because so far what12 I?ve heard from the group is that the sun?s rays hit the13 water and travel down towards the bottom of the14 container.15 Student 2: They spread out.16 Teacher: I?m sorry, they spread. I need to use your words. They17 spread across, right? That?s what you said.18 Student 2: They spread all over.19 Teacher: They spread all over. So, does anyone have any other20 ideas, or could you clarify that for me? What?s21 happening? Anthony?2 Anthony: Well, I had a new theory, um, when, the um,23 when?since the windows open, wind is coming in and24 it?s cold outside, so that comes in, it makes the room25 colder, so that that makes that room temperature. Then,26 the sun is further away from the Earth now, so it won?t27 really heat as fast with the [inaudible]?28 Teacher: Miguel?29 Miguel: I was thinking that?[inaudible]?from the top of the30 window, it?s pointed up, so solar energy might come and31 go to?32 Teacher: So, it might reflect off the window? Back up?3 288 Miguel: Yeah, and then?34 Teacher: Chen?35 Chen: I have lots of things to say?36 Teacher: Talk loud.37 Chen: I kinda agree with Miguel, but I actually think that it is38 not really air because if you?re, if the tall container is39 closer to the window, and solar energy might, it might40 have more solar energy than, um, the other container.41 And, I changed my mind and I disagree with him now,42 because the counter over there, it?s not so hot because the43 leaves make some of the shade over there, and the leaves4 are blowing, so some of it, like, solar energy will come45 only like a little bit at a time. And?that?s it!46 Student 3: The taller container is partly in the shadow.47 Teacher: Yes, I am noticing that the sun is not as bright at the spot48 as when we first came in.49 Student 3: So the, um?50 Teacher: ?let?s think about it as being the same?what if it was51 just, it was not changing. So, we?ll still take the52 temperature of those containers, but I don?t really have53 any other places in the room where there?s a constant54 source coming through the window. So, let?s just5 suppose that the same amount of sunlight was hitting56 both containers the entire discussion that we?re having. I57 want to get back, one more time, to what is happening58 when solar energy heats water. Hunter?59 Hunter: Well, what me and Brian talked about was when the solar60 energy heats the water, the water molecules are used to61 being like cold, and then when the sun heats it, they?re62 not, it?s not used to the heat, and then so the heat gets63 hotter.64 Teacher: What do you all think about that? Andy?65 Andy: Well, I think I get Hunter and I think I agree with him.6 Because, like, um, the sun is heating both containers and67 they pick-up the same amount of heat and they measure68 [?] to be the same temperature. And, I have something, I69 have, um, my Dad like makes coffee and heat puts water70 in, and puts it on the stove and since the fire comes up71 from the bottom it takes like two or three minutes to heat72 it up. But, since there is like no fire underneath them, it73 will take a long time for it to absorb the sun, and get it all74 over the two liters.75 Teacher: So, he?s saying that because it?s not a source as, I guess76 as hot as fire hitting the container right there, it?s going to7 289 take a lot longer for the heat, for the sun to, the water to78 absorb the heat?79 Andy: Like, for instance, for example, if both thermometers said80 that the water was 73 degrees each in the beginning and it81 will take like one minute to go to 70-- or 75 degrees. So,82 it?s going to take a long time to get to 100 or 90.83 Teacher: And you don?t think that the size of the container or the84 shape of the container matters?85 Andy: No.86 Teacher: Do you think that they would both heat at the same rate?87 Andy: Yeah.8 Teacher: ?or they would both heat the same amount? Okay.89 We?re gotten some new ideas about what is happening90 inside the container?to the water as the sun?s energy hits91 the container, or it is collected into the container. Brian?92 Brian: Um, I agree with Hunter, because since all the, it like93 stays out in the sun, and if it were hot, and more so,94 ?[??]95 Teacher: The water in those containers? Interesting. What do you96 all think about the molecules that Hunter?s saying the97 water molecules?what?s happening to those molecules?98 Hunter: The water starts out cold, and then when the sunrays hit9 it, the water molecules, like, they?re?they?re used to10 being cold, and then the sun hits it, gets used to the heat101 and then the water gets hot.102 Chen: They?re cold, they don?t really expand and when they?re103 hot, they expand. When you boil water, it expands and104 there are bubbles on the top. And, you will notice that105 you start out with maybe half a cup, and it expands you106 get?it expands.107 Teacher: I noticed that last night when I was making pasta. I had108 to turn the heat down because it was going to boil over.109 Sara?10 Sara: Oh. Well, what I think is happening to the molecules11 when you put it down the molecules that used to the12 water, like Jennifer said, and then, now that the sun?s not13 hitting them as much, now they are kinda like in the14 shade more. It?s like, now they?re like going back to like15 room temperature cause the sun stopped heating them to16 make them hotter anymore. The sun?s making, like17 colder. Right now the shade?s like making it a little bit18 colder. So, now I guess it?s not quite room temperature,19 but maybe a little less than it would have been if the sun120 had stayed there.121 290 Teacher: I have one last question. How does Hunter?s idea, or12 Hunter and Brian?s idea connect with Marianna?s idea?123 Cause we?Marianna?s idea was that the sun?the solar124 energy hits the container, hits the water, and spreads125 across?126 Marianna: All over.127 Teacher: ?all over, spreads all over. As it travels down? To the128 bottom? Or not?129 Marianna: Just spreads all over.130 Teacher: As it just spreads all over where ever it can. How do131 those two theories connect, or do they not connect, or132 what do you think? Go ahead.13 Student 4: Well, I think?Okay, this is mine, this is what I think.134 When a molecule gets like really hot and absorbs a lot, a135 lot of heat, and then it expands, some of the heat goes to136 the other molecule next to it, and then it goes on and on137 and on until the whole container?s full of heat. And then138 they keep getting bigger and bigger and bigger. And the139 container keeps getting hotter and hotter and hotter.140 Teacher: So that would kinda then explain what Hunter?s?I think141 that kinda goes with Hunter?s? Do you agree, Hunter?142 Do you feel comfortable with that? Miguel?143 Miguel: I agree with cause, um, [inaudible]?14 Teacher: Anthony?145 Anthony: Well, I kinda agree with Marianna because, like, um, the146 molecules when they absorb the sun, it?s like a person147 eating a lot and then getting fat, and then it spreads to the148 next one like a virus. And then it keeps going until the149 whole thing, until the whole thing?s hot. But, when the150 sun?s blocking, when the sun gets blocked, it?s like an151 antidote to that virus, and certain, and the molecules get152 skinny again. And it keeps passing down on and on and153 then it gets cooler again.154 Teacher: Excellent.15 Student 5: I kinda believe the same because, since like the water156 molecules are all over, the heat spreads towards the157 bottom, then it?s the same thing, and water molecules158 start to go up?[inaudible]159 Teacher: Okay, I?m going to give you a piece of paper and I?m160 going to ask you to draw a diagram, with labels, so I can161 really understand it when I read it, of what you think is162 happening to those containers. And then below it I want163 you to write what you think about which liter container164 will have the higher temperature. They?re both the same165 amount of water inside. Or, do you think it?s the same16 291 temperature? Or do you think it would be the same?167 Even though, yes, our sun is kinda fading away.168 292 Appendix K Young Students? Analogies Introduction The analogies from student scientific discourse presented in this dissertation have been offered as evidence that analogies are based on schemas and are contradictions to an expected schema?a story consistent with the choice of the base in generated analogies, the multiple analogies and constructed analogies, and the same story that Lakoff (1987) uses to understand categorization. In the following sections, I present instances in which young students compare astronauts in space to being in a swimming pool, magnets to clay, and magnetism to electricity. In each case, the students display confusion with their own analogy. In one case, the student is not able to relate her analogy to the case at hand?that is to say, she states the analogical base but then cannot relate it back to the target. In another case, a student asserts a meaningful analogy but then confuses being like with being an instance of. And in the final analogy presented, the student explicitly grapples with the question of ?it?s like or it is.? I argue that when these analogies are analyzed with respect to representational redescription, dual reference theory and semantic field theory, a story consistent with categorization emerges. Structure-mapping and other theories that limit analogies to pairwise analyses of the target and base would not predict and cannot account for the confusion young students show between statements of class-inclusion and statements of superordinate-class-inclusion. 293 Space as a Swimming Pool The following transcript is from a 5 th grade classroom. In a discussion about falling objects, the students were using the word ?gravity? to explain their reasoning. Curious about what the students were imagining gravity to be, the teacher asked ?what do you mean by this word, gravity?? In discussing this, some students claim that there is more gravity is space?a claim that the teacher (and this researcher) finds surprising. A student explains that in space it is difficult to move. Arguments against more gravity in space include the astronauts? ability to jump high. During this debate, the Deena presents an analogy to reconcile the competing ideas but cannot explain how this analogy relates back to gravity or the arguments that preceded: Deena: I kind of agree with both of them. It?s because like when I go in the water, it?s like I can carry like when I go into the water. It?s like you lose a little weight. ?Cause like my little sister, like her, she really can?t pick me up because I am really heavy and when I am in the water she can pick me up. Teacher: So what does that say about gravity? Deena: I don?t know. It?s like? [pause] I don?t know. Teacher: Are you connecting? Does anyone know why she said that? Rebecca: Um, I think she?s saying this because, like if you are in the water, you are still staying down on the ground, but once you are in the water you feel like you are losing gravity of yourself. Teacher: So being in water is like being in space? Why? Santiago: Like when you are in the swimming pool and like when you reach the bottom and then you can jump up high, from the bottom. That?s kind of like space. Teacher: Why is that like space? Santiago: Ah?you can jump high. To understand this passage, in which Deena is able to draw a relevant and significant analogy, but is unaware of her own reasoning, saying ?It?s like?I don?t know,? I turn to Karmiloff-Smith?s theory of representational redescription. 294 In Beyond Modularity, Karmiloff-Smith develops what she terms a ?representational redescription? model of cognitive development. In this model, she identifies four levels of representational format. These are Implicit, and Explicit 1, 2 and 3. (I, E1, E2 and E3) At level I, representations are in the form of procedures for analyzing and responding to stimuli in the external environment? Information embedded in level-I representations is therefore not available to other operators in the cognitive system? A procedure as a whole is available as data to other operators; however, its component parts are not? The E1 representations are reduced descriptions that lose many of the details of the procedurally encoded information. As a nice example of what I have in mind here, consider the details of the grated image delivered to the perceptual system of a person who sees a zebra. A redescription of this into ?striped animal? (either linguistic or image-like) has lost many of the perceptual details. I would add the that the redescription allows the cognitive system to understand the analogy between an actual zebra and the road sign for a zebra crossing (a European crosswalk with broad, regular, black and yellow stripes), although the zebra and the road sign deliver very different inputs to the perceptual system? The RR [representational redescription] model posits that only at levels beyond E1 are conscious access and verbal report possible. At level E2, it is hypothesized, representations are available to conscious access but not to verbal report (which is possible only at level E3)? we often draw diagrams of problems we cannot verbalize? At level E3, knowledge is recoded into a cross-system code. This common format is hypothesized to be close enough to natural language for easy translation into statable, communicable form. These levels have been empirically verified. In one experiment described in Beyond Modularity, children were shown playrooms of a boy doll with a single toy car and a girl doll with three toy cars. The children were asked to which doll the experimenter was speaking if she said ?Lend me the car? or ?Lend me a car.? By age 3, children have achieved behavioral mastery at this task, correctly assigning ?the car? to the boy doll (who has one car) and ?a car? to the girl doll (who has multiple cars). However, around 295 age 5 and 6 these children start to make mistakes. Karmiloff-Smith argues that ?representational redescription of each of these procedures into the more explicit E1 format makes it possible to link the common phonological form across the two representations of form-function pairs? In comprehension they start to make mistakes as to which of the two functions (numeral or indefinite reference [?one? or ?one of?]) is intended.? (p 57) That is to say, at the I-level students have a ?black box? algorithm for arriving at an analogical map: they have a schema but aren?t aware of that schema, are not aware of the instances from which that schema was derived, and are not able to pick apart how a new item (in this case outer space) is judged to be a member of that schema. Even more startling and provocative evidence for the implicit level comes from the reports of the children as to the reasoning they report for making their choice: the youngest subjects, even though they must have used the contrast between the articles to make their correct guess, explain this on the basis of real-world knowledge, saying something along the lines of ?You must have been talking to the boy, because boys like cars? Later in development, children explain their correct guesses by referring to the contextual features?for example, ?You were speaking to the boy, because he?s got one car.? It is really rather late in development, around age 8 or 9, that children make explicit reference to the linguistic clue that all children must have in fact used. (p 59) When the teacher asks ?Does anyone know why she said that?? she is, unwittingly perhaps, adopting the representational redescription model of students? levels of explicitness in their knowledge. Deena is able to draw a correct and relevant analogy, but is unaware of her own reasoning, saying ?It?s like? I don?t know.? Rebecca, in hearing the analogy, is able to abstract slightly?equating the feeling of being in water to ?losing gravity.? And Santiago relates this to space because in both places ?you can jump high.? 296 This raises an interesting question regarding my definition of analogy as a conscious choice?a deliberate reclassification of the object, subject to a new cognitive model (which may be interpreted as a distinct ?form of procedures for analyzing and responding to stimuli in the external environment? (from Karmiloff-Smith, quoted above)). At what level of representational redescription are students able to make conscious decisions regarding their response to stimuli and deliberately reclassify objects? Magnets as clay, magnets as electricity The children in the above transcript are in the 5 th grade?placing them at an age where Karmiloff-Smith observed linguistic abilities to be at the E2 and E3 levels. In the following transcript, I present data from a 2 nd grade classroom. These students are between the ages 7 and 8 and, according to Karmiloff-Smith, less able to reason explicitly about concepts. Here this is evidenced by the confusion the students have using the analogies that they create. In this transcript, the students are discussing what?s ?inside? a magnet that makes it behave the way it does (lines 48 ? 56). Renee: I think there is clay inside of it because clay does pick stuff?things, like paper and stuff. Teacher: Okay, so if there?s clay inside here, does that help it stick to things? That helps the magnet stick? Ok, does it stick to paper, like clay does? Renee: Ummmm. Teacher: Okay, so the clay that?s in here that you?re saying is in here? what does it help the magnet stick to? Renee: Metal. And later in the conversation (lines 92 ? 97): Dalton: Because Evan said um well?I was thinking in my head when he said that there?s magnets inside there?what are in 297 the other?what are in the magnets that are inside the big magnet? Evan: Little pieces of metal. Teacher: Little pieces of metal? Dalton: Then what?s inside them? Student: Yeah- what?s inside the little pieces of metal? Taylor: Clay. Teacher: Oh, Taylor has an answer, she says clay. And following up on these comments (145 ? 151): Student: I am confused with Taylor. Teacher: About what? Be specific what are you confused about. Student: What she said before um Calvin was talking? Teacher: You mean about the clay inside? Student: Yes. Teacher: Okay?do you want to add on to that? Taylor: Um?I don?t know what she?s talking about. There is something reasonable in Renee?s statement?although neither she nor Taylor can articulate it and other students may not see it. There are a limited number of things that can stick to, say, your refrigerator and not fall down. Clay and magnets have crucial differences, of course, but more intriguing here is that Renee explains her reasoning that clay is inside magnets by stating: ?clay picks stuff up.? Is she thinking that there is, quite literally, standard modeling clay inside the magnet? Or is it more plausible that she is using clay as a prototypical member of the category of things that can ?pick stuff up??but do so in a way that does not fit with our standard p-prim of carrying? For while she uses the term linguistically in the first sense, if we recognize her knowledge to be at a less explicit level than language can effectively express, it is reasonable to believe that she ?means? the second sense. Taking into account that languages often name categories after their prototypical or prevalent members (i.e. a Xerox machine for any copy machine), I contend that Renee is creating an analogy between the magnet and clay, 298 assigning them to a category that she is terming ?clay? because clay is an everyday object to a 2 nd grade student. The students (including Renee and Taylor, proponents of the clay ?theory?) do not recognize that clay is serving as the name of a category and not the thing itself and argue against the clay-theory by stating that ?clay?s not that black? and suggesting perhaps the blackness is due to ?food coloring? (again, ?food coloring? may, to a young student, be a fairly standard way of changing the color of objects and so is used here as a way of signifying that color must be added?not necessarily food coloring). When the base of an analogy (termed the vehicle in the context of metaphor) is used as both an exemplar and as an ad hoc name for a category, Glucksberg et al. (1997) all this linguistic move ?dual reference.? As an example of dual reference, the phrase ?a responsibility is a shackle? can be used to refer to the concrete, physical device that is made of metal, often has chains, can be locked around someone?s arms and legs, and so forth, and it can also be used to refer to the abstract, general category of constraining entities. We refer to such abstract, general concepts as attributive categories. (Glucksberg et al 1997 p 334) The authors claim that ?nouns can be used to make dual reference whenever a superordinate category has not been lexicalized and a category exemplar is available that is prototypical of that category.? What I hope to have demonstrated with the above data on ?clay? is that this dual reference is an ability that young students have, but, consistent with findings from representational redescription do not have access to the ?duality? of the reference: is a magnet a member of a superordinate category typified by clay or is it a member of a category of things that are clay? The question of ?being like? versus ?being? is addressed in the same magnets conversation in a different context. While Renee has identified clay as an appropriate 299 analogy because of the ability of both clay and magnets to pick things up, other students are curious about the ability of a magnet to exert a force through things and one suggests electricity as an analogy (lines 212 ? 214). Teacher: ?He said this is a magnet, it?s only a magnet, there?s nothing in it except electricity. Calvin: Electricity and the magnet. After asked to explain, Dalton jumps in with a theory and the teacher summarizes his comments (lines 251 ? 271): Teacher: Okay, so to make this magnet work somebody hooked it up to a wire, pushed the on switch, stuff came down through the wire to the magnet? Dalton: Electricity. Teacher: Electricity did?and now the magnet works? Dalton: Mmm hmm. It?s kind of like that?it?s magnetism. Teacher: ?It?s kind of like that??you keep telling me that??it?s kind of like that.? Dalton: Well it?s not kind of like um?electricity. It?s magnetism that flows down. Teacher: Okay, do I have to plug this in to a wire? Dalton: No?when you?re making it. Teacher: When I?m making it I have to plug it in. [Dalton: Yeah.] and give it magnetism. [Dalton: Yeah.] Okay. Who else has some thoughts on that process?Savannah? Savannah: I have two thoughts on that. Teacher: Okay?go ahead. Be nice. Savannah: Make up your mind already! Between it kind of has something? Dalton: That?s hard to do! [Teacher: Okay.] It?s hard to do both at the same time! Teacher: Okay so Savannah what?s your question. Specifically what?s your question?what are you confused about?you?re saying make up your mind Dalton. Between what and what? Savannah: Kind of and it is. Or it isn?t. The students recognize that there is a fundamental difference between the magnet being electricity and it being like electricity, but Dalton is still unsure why he claims it might be electricity in the magnet. Were this an unreasonable assertion with no cognitive 300 ?meaning? in his statement, it would be indecipherable to a scientist. There is logic to his statement. Both are instances of the schema of action-at-a-distance?something rarely seen in daily activity (and not shared by clay?at least not on visual distance scales). And in this schema the property responsible for that action may have ?electricity? as a prototype. (Dalton, after suggesting electricity, is asked what electricity is and relates an experience with being shocked.) In fact, in a true scientific description of the phenomena, electricity and magnetism are manifestations of the same electro-magnetic force, and any motion produced by a magnet is due to the electrical manifestation of that force. Dalton is onto something?but his grasp is at the E-1 level of representational redescription. In essence, when Dalton states ?they used wires to put it [electricity] in. That?s why, um, some of them [the magnets] have little holes left from it?I?ve seen ?em,? or when Renee claims that she ?went on this website about magnets and it said that there?s clay inside? they are doing the same thing as the child who explained why the experimenter must have been referring to the boy doll by saying: ?You must have been talking to the boy, because boys like cars.? Because these students don?t have access to their own reasoning, they have to invent a plausible reason that is, in fact, less plausible than the actual reason that they must have had, but not had access to. This lack of access to one?s own reasoning echoes diSessa?s findings (also reported in an chapter 5) concerning a problem in which students are presented with bells made of the same material, same length, same height, but varying widths. Almost without exception students predict (erroneously) that the thicker bells will have a lower pitch. Though some have cognitive access to the schema they are using to predict this and can refer to 301 particular instances from which this schema has been abstracted, not all do. DiSessa reports: Although most subjects were ready with analogies?church bells compared with jingle bells, xylophones, musical instruments of various sizes?I was struck that some initially could not produce any example of the phenomenon they identified to be at the root of the situation. This, along with the rapidity and expressed certainty of responses, heightened my confidence that a p-prim (or several) was at stake rather than analogy. I think these youngest students have trouble separating the schema from the instance (that is clay from things-that-stick?a category typified by clay); but later (older students) have trouble putting them back together (as with bigger-means-lower and the xylophone). 302 Glossary Analogy: The claim of likeness where it is not routinely or automatically conceived. Analogy includes similes and metaphors. I define analogy to entail the choice of an alternative cognitive model. Category: Commonly considered ?a group or set of things, people or actions that are classified together because of common characteristics.? Known not to possess rigorous propositional structure (i.e., they are not always grouped by common characteristics), it has been suggested (Lakoff, 1987) that the boundaries between categories are a result of cognitive models. Cognitive model: ?Can be viewed as ?theories? of some subject matter? (Lakoff, 1987). May be an ad hoc construction, a kind of ?story? of how the world works in a particular situation. Our cognitive models define our categories (for example, it only makes sense to differentiate a bachelor from a non-bachelor when you have a cognitive model in which people reach a marriageable age and enter monogamous long-term relationships). Metaphor: A figure of speech in which two things are compared, usually by saying one thing is another, or by substituting a more descriptive word for the more common or usual word that would be expected. Some examples of metaphors: the world's a stage, he was a lion in battle, drowning in debt, and a sea of troubles. As noted by Glucksberg and Keysar (1990) one may note similarity by saying that copper is like tin, but not the metaphorical construction copper is tin. Metaphor, then, is used as a comparison between two categorically related items when no commonly accepted name for the category exists (for example, copper is metal). Phenomenological Primitive: ?The intuitive equivalent of physics laws; they may explain other phenomena, but are not themselves explained with the knowledge system? (diSessa, 1993). Examples include ?closer is stronger? (as an explanation for why it is hotter closer to a fire), ?blocking? (as an explanation for why a car is stopped when it hits a wall), and ?supporting? (as an explanation for why a book is held up by a table). These are basic stories that convey an elemental sense of mechanism. Prototype: Defined operationally by Rosch, this is a category member that is easily learned, easily identified, can be used to generalize about the entire category, and comes to mind most quickly as a category exemplar. Barsalou points out that prototypes are a cognitive behavior and not cognitive structure. Lakoff points to the role of cognitive models as a possible cognitive mechanism for the prototype structure of categories. Schema: Short ?scripts? or stories that we have about the world and the way it works: event schemas that are abstracted from our experience of certain events, image schemas that provide structure for conceptualizations ? ?schemas of intermediate abstractions [between mental images in abstract propositions] that are readily imagined? 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Information and Control, 8, 338-353. 312 Curriculum Vitae Leslie Atkins Department of Physics Department of Education and Curriculum University of Maryland Education: Ph.D, December 2004 Analogies as Categorization Phenomena: Studies from Scientific Discourse University of Maryland M.S., Physics, 2004 University of Washington B.S., Physics, 1998 University of Virginia Memberships: Cognitive Science Society International Society of the Learning Science American Physical Society American Association of Physics Teachers Fellowships: Graduate NSF G/K-12 Fellowship Program PRIME: Partnership for Research in Math-science-engineering Education University of Washington, 2000-2001 Undergraduate NSF Research Experiences for Undergraduates University of Washington Eotwash Group, Eric Adelberger 1996 NSF Research Experiences for Undergraduates University of Virginia Neutron Spin, Donal Day 1997 313 Teaching Experience: University of Maryland Physics 115, Fall 2004 (instructor of record) Physics 115, Spring 2003 (co-instructor) Physics 121 (TA) The Governor?s School of North Carolina 2003, 2004 Physics Self & Society University Preparatory High School 10 th grade Environmental Chemistry, 2002 University of Washington Lead Teaching Assistant, Physics 121, 122, 123. 1998, 2000 Physics 321 Lab TA. Seattle Girls? School Mentor Garfield High School Saturday-School tutor Workshops: Co-led: Analysis of Student Inquiry in Group Conversations About Physical Science at NSTA 2003. Building Capacity for Professional Learners. Montgomery County Public Schools, 2003. Workshop in physical science for in-service teachers. King County Public Schools. 2001, 1999. Summer Institute in Physics and Physical Science. University of Washington, 1998. Participant: Doctoral Consortium. International Conference on the Learning Sciences. 2004. National Outdoor Leadership School, New Zealand. 2004. Public Conversations Project: Inquiry as Intervention. 2003. Preparing Future Faculty: Teaching and Learning in Higher Education. 2001. Publications: L.J. Atkins. Phenomenological Primitives as Idealized Cognitive Models: A Basis for Graded Structure in Scientific Categories. Proceedings of the 2004 EDCI Symposium. Atkins, L.J. Student Generated Analogies in Science: Analogy as Categorization Phenomenon. Proceedings ICLS 2004. G.T. Seidler, L.J. Atkins, E.A. Behne, U. Noomnarm, S.A. Koehler, R.R. Gustafson, and W.T. McKean, ?Applications of synchrotron x-ray microtomography to mesoscale materials.? Advances in Complex Systems. Vol. 4, issue 4. Atkins, L.J., E. Behne, G. Martinez, J. Rensberger, and G.T. Seidler. X-ray microtomography of the vascular canal network in permineralized Triceratops bone. Advanced Photon Source User Activity Report. G.T. Seidler, E. Behne, L.J. Atkins, and A. Rendahl. X-ray microtomography study of a model crumpled membrane. Advanced Photon Source User Activity Report 314 Presentations: An Experimental Study of Bond-Orientational Order in Random Dense Packings of Spheres. Atkins, L.J., Martinez, G., Seeley, L.H., and Seidler G.T. APS March Meeting 2001 Functional vs. Structural Analogies: A Conceptual or Epistemological Basis? Atkins, L.J., Hammer, D. and Hutchison, P. 127th AAPT National Meeting: Madison, WI August, 2003. Phenomenological Primitives as Idealized Cognitive Models: A Basis for Graded Structure in Scientific Categories. Atkins, L.J. Graduate Student and Teacher-Researcher Symposium, April 2004. Student Generated Analogies in Science: Analogy as Categorization Phenomenon. Atkins, L.J. International Conference on the Learning Sciences, June 2004. A graduate physics course in physics education research for physics education graduate students. Scherr, R.E. and Atkins, L.J. 128th AAPT National Meeting, August 2004.