Some Determinants of the Persuasive Power of In-Groups and Out-Groups: Organization of Information and Attribution of Independence

Four experiments examined the hypothesis that in-groups exert more influence than do out-groups. The hypothesis was supported using both laboratory groups of university students and a natural social category (university affiliation). Subjects exposed to in-group communicators attributed greater independence to them, made fewer errors in recalling their messages, and clustered recollections of messages by individual speaker. In addition, the persuasiveness of out-group members was enhanced when individuating information was provided about them that increased their heterogeneity. The individuated out-group members were as influential as in-group communicators. Results were interpreted in terms of attribution and social identity processes.