Abstract

Models and Analogies in Conceptual Restructuring Moderator: Dedre Gentner ([email protected]) Northwestern University, Department of Psychology 2029 Sheridan Road, Evanston, IL 60208 Participants: Theodore Arabatzis ([email protected]) and Despina Ioannidou Department of Philosophy and History of Science University of Athens Nancy J. Nersessian ([email protected]) School of Interactive Computing, Georgia Institute of Technology Atlanta, GA 30332-0280 Stella Vosniadou ([email protected]) and Irini Skopeliti ([email protected]) Department of Philosophy and History of Science University of Athens John J. Clement ([email protected]) School of Education and Scientific Reasoning Research Institute University of Massachusetts at Amherst The purpose of this symposium is to bring together recent work on the role of analogies and models in conceptual restructuring from cognitive scientists representing different disciplines and examining similar phenomena from diverse perspectives. Theodore Arabatzis and Despina Ioannidou approach the topic from a philosophy and history of science perspective. Their contribution focuses on the analysis of the ways in which the planetary model mediated the conceptual transformation of J. J. Thomson’s ‘plum-pudding’ model of the atom and transformed the concept of the electron. Cognitive analyses of conceptual changes in the history of science are rare but particularly important from a cognitive science point of view because they provide an opportunity to understand very complex kinds of conceptual processes over long periods of time that are difficult if not impossible to study in the laboratory. Nancy Nersessian is using cognitive-historical ethnographic methods to study how engineering scientists create in vitro models of the phenomena they want to study and manipulate them in order to understand them. As she explains, engineering science is fundamentally analogical practice since simulation models are analogue representations of the entities and processes under study. Stella Vosniadou and Irini Skopeliti approach the topic from a cognitive developmental point of view. They are interested in finding out whether elementary school children can understand analogies and models and can use them to restructure existing knowledge in the process of learning science. John Clement approaches the topic mostly from a science education point of view. He has studied the role of models and analogies in promoting the understanding of science concepts for a very long period of time and has developed an integrating framework that identifies several roles for analogies and explicates the kinds of conceptual changes they promote. The moderator of this symposium is Dedre Gentner who is internationally known for her pioneering work on analogy. Theodore Arabatzis and Despina Ioannidou The mediating role of models in conceptual transitions: how the electron became a quantum entity The extensive philosophical literature on models has focused on their role as mediators between theories and their empirical domains. With a few notable exceptions (e.g. Morgan & Morrison, 1999; Nersessian, 2008), their role in effecting conceptual change has not been explored. In this paper we discuss this particular function of models via a case study: the transition from a classical to a quantum theory of atomic structure (or, equivalently, from a classical to a quantum concept of the electron). In that transition the model of the atom as a planetary system (or, equivalently, of the electron as a planet) was rather crucial. In 1911 Ernest Rutherford abandoned the plum-pudding model of the atom, which had been developed by his mentor J. J. Thomson, in favor of a planetary model. The latter was suggested by experiments on the scattering of alpha-particles, which indicated that the mass of the atom is concentrated near its center. Despite its empirical grounding, however, the planetary model gave rise to severe conceptual and empirical difficulties. If the atom were structured as a miniature planetary system, it would have to be mechanically unstable. Furthermore, it would have to continuously emit radiation, until its eventual collapse. In response to those difficulties, Niels Bohr modified the planetary model, incorporating assumptions from the fledgling quantum theory and transforming in the process the concept of the electron. Thus, the planetary model functioned as a mediator between two successive versions of the concept of the electron. (Arabatzis, 2006). The focus of our analysis will be the heuristic and constraining function of that model in that conceptual transformation.