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Are Theories Necessary to Constrain Concepts?

 Timothy T. Rogers and James L. McClelland
  
 

Abstract:
Abstract: In traditional theories of semantic memory, performance of semantic tasks relies upon a mediating process of categorization. However, categorization-based theories do not capture the complex and flexible ways in which people use their conceptual knowledge to perform natural semantic tasks imposed on them by the environment. For example, both children and adults understand that a given property may be important for categorizing some kinds of objects, but not others; that different kinds of properties generalize across different groups of objects; and that insides can be more important for determining category membership than outsides. Consequently, some researchers propose to describe conceptual knowledge in terms of naive theories about causal mechanisms. In the current work, we present simulations using a simple connectionist network that learns the mappings between objects and their properties in different contexts. We show that the evolution of representations throughout learning in our model constrains the ease with which particular object properties can be learned, and how they will generalize. The configuration of weights at any point during development may provide the kinds of `enabling constraints' on acquisition that some researchers attribute to naive theories. Many of the phenomena that arise in the theory-theory tradition may be understood within this framework. Knowledge about how object properties vary across contexts is stored in connection weights that are learned from experience. This knowledge plays the role that naive theories play in the theory-theory framework.

 
 


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