Proceedings of the Annual Meeting of the Cognitive Science Society

According to the instantiation principle, when we make a judgment about a relatively superordinate category, we follow a two-step process. First, we instantiate the category into one or more subordinates. SeoHid, we make a judgment based on the subordinates. Instantiation theory :q>plied to typicality judgments makes the following predictions. W h e n subjects judge the typicality of a category A with respect to categ(My B, their mean typicality judgment should equal the weighted mean typicality (with respect to B ) of subwdinate categories of A. Furthermore, typicality judgments for category A will be unstable (i.e., have a high standard deviation) to the extent that A has a large number of diverse subordinates. The instantiation principle was implemented in a computer simulation, which used production frequencies and typicality ratings for subordinates to predict ratings for superordinate-level categories. In two experiments, subjects judged the typicalities of various animal and food categories. The instantiation model successfully predicted the means and standard deviations for the observed distributions of responses for these categories. Extensions and other applications of the instantiation principle are also briefly discussed.