Type of category rules affects the occurrence of categorical perception

Previous studies (e.g., O »zgen & Davies, 2002) have demonstrated that learning novel categories induces categorical perception (better discrimination for between-category pairs than for withincategory pairs). On the other hand, Ashby, Alfonso-Reese, Turken, and Waldron (1998) have argued that the rule-based (RB) category, which is defined in terms of verbalizable rules, and the information-integration (II) category, which is defined in terms of nonverbal rules, are learned by different systems. The present study investigates whether the learning of the RB and the II categories produces categorical perception. Ten participants learned the RB category and another 10 learned the II category. Another 15 participants did not learn any category. After category learning, the participants performed a delayed discrimination task. The results showed that the accuracy for between-category discrimination was higher than that for within-category discrimination in the RB category learners. However, this between-category advantage was not observed in the II category learners. The results suggest that RB category learning, but not II category learning, produces categorical perception. The relation between category learning and categorical perception is discussed.