Proceedings of the Annual Meeting of the Cognitive Science Society

Comparison is of two types, the implicit sort that is behind all categorization and the explicit sort by which two object representations are compared in short-term memory. Children learn early on both to categorize and to compare explicitly, but they only learn to use dimensions in these processes considerably later. In this paper we present a connectionist model which brings together categorization and comparison, focusing on the development of the use of dimensions. The model posits (1) a general comparison mechanism which is blind to the nature of its inputs and (2) the sharing of internal object and dimension representations by categorization and comparison processes. Trained on the two processes, the system learns to use dimension inputs as filters on its representations for objects; it is these filtered representations which are matched in comparison. The model provides an account of the tendency for early comparison along one dimension to be disrupted by similarities along other dimensions and of the process by which the child might overcome this deficiency.