SIMILARITY-BASED CATEGORIZATION - THE DEVELOPMENT OF PROTOTYPE THEORY

It is now twenty years since Rosch and Mervis first published the mass of evidence on which the Prototype Theory of concepts was originally based (Rosch, 1977; Rosch & Mervis, 1975). The theory has evolved many varieties over the years - varieties which have rarely been made expl icit. These different ways of interpreting the notion of a prototype h ave often been a worrying source of vagueness and confusion in the the ory. In this article these different interpretations will be examined by looking at the kinds of attribute which could be involved in a prot otype representation, and discussing how the model could be formulated in each case. It will be argued that a key element required for a suc cessful model of prototypes is the element of abstraction, and that ce rtain versions of Prototype Theory that lack this element are inadequa te as a result.