Concepts as Prototypes

Abstract

This chapter reexamines prototype theory and the evidences with which it is associated. In general, the way in which prototype structure was demonstrated for a domain was to establish one or more of four key phenomena about categories in that domain. The four key phenomena are vagueness, typicality, genericity, and opacity. These are well documented and they constituted the basis on which domains as different as syntactical word classes, phonetic categories, speech perception, speech acts, psychiatric diagnosis, and personality perception were given a prototype treatment. For Prototype Theory the determination of extension is achieved by specifying a measure of the match between the representation of an object or class and the prototype representing the category. Category vagueness provides support for prototype representations given an additional assumption that the representation itself or the processes that utilize that representation are subject to random or contextual noise. Variation in the typicality of category members is often cited as one of the core tenets of Prototype Theory. However, it is questionable whether the simple fact of typicality variation itself is particularly discriminating between Prototype Theory and other accounts of concepts. The problem is that when instructed to judge typicality or goodness-of-example it may be unclear just what aspect of the category members people may be attending to. Typicality effects can be identified that are not simply to do with the familiarity or availability of category members. Theories of concepts that do not base categorization on similarity tend to be dismissive of typicality effects. The fourth phenomenon considered to support a prototype view of concepts is the difficulty that has been encountered in generating good accurate definitions of the meanings of content words (particularly nouns and verbs) in any language.