Category learning by inference and classification

The nature of category formation is linked to the tasks applied to learn the categories. To explore this idea, we investigated how three different methods of category learning-Classification Learning, Inference Learning, and Mixed Learning (a mixture of the two)-affect the way people form categories. In Classification Learning, subjects learned categories by predicting the class to which an individually presented exemplar belonged given feature information about the exemplar. In Inference Learning, subjects learned categories by predicting a feature value of a stimulus given the class to which it belonged and information about its other features. In Mixed Learning, subjects received the Classification task on some trials and the Inference task on other trials. The results of two experiments and model fitting indicate that inference and classification, though closely related, require different strategies to be carried out, and that when categories are learned by inference or by classification, subjects acquire categories in a way that accommodates these strategies. (C) 1998 Academic Press.