Proceedings of the Annual Meeting of the Cognitive Science Society

Ail existing accounts of similarity assume that it is a function of matching and mismatching attributes between mental representations. However, Bassok and Medin (19%) found that the judged similarity of sentences does not necessarily reflect the degree of overlap between the properties of paired stimuli. Rather, similarity judgments are often mediated by a process of thematic integration and reflect the degree to which stimuli can be integrated into a common thematic scenario. We present results of a study which extend this surprising flnding by showing that it also applies to similarity ratings of objects and occurs whether or not subjects explain their judgments. Also, consistent with the Bassok and Medin findings, the tendency towards thematic integration was more pronounced when the paired stimulus shared few attributes--but was still an important factor in similarity judgments between objects which shared many attributes. We discuss the implications of these findings for models of cognitive processes which use similarity as an explanatory construct.