SIMILARITY-BASED CATEGORIZATION AND FUZZINESS OF NATURAL CATEGORIES

The adequacy of similarity to prototype as an account of categorizatio n in natural concepts was assessed by analyzing the monotonicity of th e relation between typicality of an item in a category and the probabi lity of a positive categorization response using data from McCloskey a nd Glucksberg (1978). The analysis revealed a strong underlying simila rity-based threshold curve, with systematic deviations. Further data c ollection showed that deviations from the curve could be attributed to the effects of unfamiliarity and non-categorial associations on typic ality judgments, as well as differences between the perceptual appeara nce of an item (which tended to boost typicality) and its underlying n ature (which tended to boost categorization). The results are discusse d in terms of the different presuppositions and task constraints invol ved in rating typicality as opposed to performing a categorization. (C ) 1998 Elsevier Science B.V.