Studies of Similarity

Any event in the history of the organism is, in a sense, unique. Consequently, recognition, learning, and judgment presuppose an ability to categorize stimuli and classify situations by similarity. As Quine (1969) puts it: “There is nothing more basic to thought and language than our sense of similarity; our sorting of things into kinds [p. 116].” Indeed, the notion of similarity – that appears under such different names as proximity, resemblance, communality, representativeness, and psychological distance – is fundamental to theories of perception, learning, and judgment. This chapter outlines a new theoretical analysis of similarity and investigates some of its empirical consequences.