The category effect in social judgment: experimental ratings of happiness.

Three experiments demonstrated the applicability of a range-frequency analysis to social judgments. Subjects rated the happiness of either (a) schematic drawings of faces or (b) life events as expressed in short verbal descriptions. The relative frequency of these stimuli was manipulated experimentally, as was the number of rating categories. Consistent with psychophysical research, ratings became less sensitive to differences in the frequencies of contextual stimuli as the number of categories increased (the category effect). With more categories, ratings also showed less adjustment to the range of stimuli actually presented. The reduction in adjustment was greater when stimuli were presented successively and when the experimental set covered a limited range. These effects of varying the number of categories were interpreted as reflecting changes in the effective context for judgment: With more categories, the differences between the effective frequencies of contextual stimuli are reduced and new, more extreme comparison values are evoked. The implications of using coarse versus fine scales of judgment are discussed in terms of the dynamics of social judgment as well as choice of the appropriate number of categories in social research. We argue that selection of the number of rating categories should be guided by research objectives rather than by a search for "true" judgments.