Proceedings of the Annual Meeting of the Cognitive Science Society

Does categorization involve more than the similarity of an item to a category prototype or other category members? Rips (1989) argues yes, because categorization and similarity ratings sometimes diverge, indicating that they are based on different factors. However, Smith and Sloman (1994) suggest that such categorization/similarity dissociations may be limited to special conditions. We examined the effect of causal relationships between category attributes on categorization and similarity, and found that causal knowledge had a much larger effect on categorization than on similarity. This result was obtained with stimuli rich in characteristic attributes and without participants thinking aloud, that is, in just those conditions where Smith and Sloman found categorization to be solely similarity-based. Thus, the categorization/similarity dissociation demonstrated by Rips is alive and well, and the need for an account of categorization that goes beyond similarity is again highlighted.