MEMORY-BASED JUDGMENTS ABOUT MULTIPLE CATEGORIES - A REVISION AND EXTENSION OF TAJFELS ACCENTUATION THEORY

Accentuation theory states that the classification of stimuli produces encoding biases. Contrast effects enhance intercategory differences; assimilation effects enhance intracategory similarities. Do these biases affect the retrieval of stimuli distributed across many categories? The calendar superimposes arbitrary intermonth boundaries on day-to-day variations in temperature. In Experiment 1, Ss estimated the average temperatures of 48 days. Differences between estimates for 2 days belonging to neighboring months were greater (contrast) and differences between estimates for 2 days belonging to the same month were smaller than actual differences (assimilation). Experiment 2 showed that assimilation accounted for all categorization effects. When modified by assumptions from an exemplar model of category learning, accentuation theory accounts for the results. The relevance of these findings for social categorization is discussed.