Beliefs Versus Knowledge: A Necessary Distinction for Explaining, Predicting, and Assessing Conceptual Change

Beliefs Versus Knowledge: A Necessary Distinction for Explaining, Predicting, and Assessing Conceptual Change Thomas D. Griffin (tgriffin@uic.edu) Stellan Ohlsson (stellan@uic.edu) Department of Psychology, 1007 West Harrison Street (M/C 285) Chicago, IL 60607, U.S.A. Abstract Empirical research and theoretical treatments of conceptual change have paid little attention to the distinction between knowledge and belief. The distinction implies that conceptual change involves both knowledge acquisition and belief revision, and highlights the need to consider the reasons that beliefs are held. We argue that the effects of prior beliefs on conceptual learning depends upon whether a given belief is held for its coherence with a network of supporting knowledge, or held for the affective goals that it serves. We also contend that the nature of prior beliefs will determine the relationship between the knowledge acquisition and the belief revision stages of the conceptual change process. Preliminary data suggests that prior beliefs vary in whether they are held for knowledge or affect-based reasons, and that this variability may predict whether a change in knowledge will result in belief revision. Introduction Theorists and researchers tend to agree that prior concepts often impede people's ability to learn conflicting information (e.g., Chi, 1992; Dole & Sinatra, 1998; Thagard, 1992). The paradox of knowledge acquisition is that new information can only be understood in terms of existing ideas, yet existing ideas act as a filter, often distorting new information to make it more consistent with prior concepts. This raises the question of how we ever learn anything fundamentally new. At least two widely cited models agree about crucial steps in the conceptual change process (Chi, 1992; Thagard, 1992): (1) recognizing that the new information conflicts with (or is fundamentally different from) existing concepts; (2) constructing a new knowledge structure to support the new information; (3) replacing the old concepts with the new, more coherent concepts. In short, conceptual change involves learning new concepts and then substituting them for the old. Though these models (i.e., Chi, 1992; Thagard, 1992) diverge in some of the details about the process, they seem to agree that conceptual coherence largely determines conceptual replacement. In addition, Ohlsson and Lehtinen (1997) have suggested that the use of abstract schemas may be needed to explain how new knowledge representations can be created that will not be distorted by the conflicting prior concepts. They suggest that activation of conflicting prior concepts activates related abstract concepts that are not in direct conflict with the new information, and that can be utilized in constructing an accurate representation of the new information. These aspects of the conceptual change process become more important when we consider how beliefs differ from knowledge. Belief Versus Knowledge The present paper defines knowledge as the comprehension or awareness of an idea or proposition ( I understand the claim that humans evolved from early primates ). After a proposition is known, one can accept it as true ( I believe the claim that. ), reject it as false ( I disbelieve the claim that. ), or withhold judgment about its truth-value ( I have no opinion about the claim that. ). The present knowledge/belief distinction is intended to be psychological. Thus, knowledge and belief refer to qualitatively different aspects of the mental representation: knowledge refers to the representation of a proposition, and belief refers to the representation of a truth-value associated with a proposition. These definitions are consistent with Quine, and Ullian's (1970) argument that people can have knowledge of an idea or proposition, but either not believe it to be true, or hold a belief that the concept is false. A proper distinction between comprehension versus acceptance or rejection of an idea allows us to consider the multiple influences on belief formation, and to speak more clearly (and realistically) about the relationship between knowledge and belief change. A Change in Knowledge, Beliefs, or Both? It is striking that discussions of conceptual change use the terms 'knowledge', 'beliefs', and 'prior conceptions' interchangeably. Recently, diSessa (2000) highlighted the unexamined lack of agreement among conceptual change researchers regarding basic issues such as whether the conceptual change refers to a change in concepts, beliefs, nodes, or links.