Limitations of exemplar-based generalization and the abstraction of categorical information

An evaluation of exemplar-based models of generalization was provided for ill-defined categories in a category abstraction paradigm. 72 undergraduates initially classified 35 high-level distortions into 3 categories, defined by 5, 10, and 20 different patterns, followed by a transfer test administered immediately and after 1 wk. The transfer patterns included old, new, prototype, and unrelated exemplars of which the new patterns were at 1 of 5 levels of similarity to a particular training (old) stimulus. In both experiments, increases in category size and old-new similarity facilitated transfer performance. However, the effectiveness of old-new similarity was strongly attenuated by increases in category size and delay of the transfer test. It is concluded that examplar-based generalization may be effective only under conditions of minimal category experience and immediacy of test; with continued category experience, performance on the prototype determines classification accuracy. (22 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved).