Differences in consumer perceptions of similarity and dissimilarity

Researchers have usually treated similarity ratings as the simple inverse of dissimilarity ratings. Tversky's theory of perception of similarity and dissimilarity (1977), however, explicitly recognizes that the attributes used in the perception of similarity and the attributes used in the perception of dissimilarity are decidedly different. In fact, the weights assigned to common and distinctive features changes according to the task at hand (i.e., when similarity is to be rated the common features are weighted more, and when dissimilarity is to be rated the distinctive features are weighted more). This study demonstrates these differences in a judgment task of rating similarity and dissimilarity on the basis of data that is external to the subjects.