Determinants of intergroup differentiation in the illusory correlation task

Illusory correlation refers to the perceived (but erroneous) relation betwe en stimuli. In social psychology this phenomenon has been related to stereo type formation. Recent research in this area has shown that the perception of illusory correlation between two groups and their behaviours can be a pr oduct of understandable attempts to differentiate between these groups. Thi s is due to participants' interpretations of the experimental task and to f eatures that draw attention to group differences. In the first study we sho wed that the task instructions presented to participants can induce expecta tions of differences between the stimulus groups, which helped to produce i llusory correlation. We also demonstrated that giving precedence to the beh aviours, rather than to the groups, resulted in attenuated illusory correla tion effects. In the second study we investigated how aspects of the stimul us distribution affected the perception of illusory correlation. In line wi th the first study, we showed that increasing the focus on the stimulus gro ups can enhance illusory correlation, whereas focusing on the behaviours ca n reduce this effect. The present findings support the self-categorization explanation of illusory correlation that proposes it to be the product of a meaningful category differentiation process.