A test between deindividuation and emergent norm theories of crowd aggression

In groups of 6-8, 89 female undergraduates who were either anonymous or identifiable to each other acted as an audience to a pair of discussants. Ss were given the opportunity to administer loud noise to the discussants. The response displayed to each group as an alleged average was manipulated so that Ss were led to believe that either an aggressive or a lenient norm had developed. As predicted by deindividuation theory, anonymous Ss administered significantly higher levels of noise than identifiable Ss. Anonymous Ss used equally loud noise regardless of group norm. Self-ratings provided evidence that the effects of anonymity were mediated by a psychological state of deindividuation, in addition to freedom from accountability for individual acts. There was no support for the crucial emergent norm theory prediction that aggression will be greatest when Ss who are identifiable to each other are exposed to an aggressive norm. (26 ref)