Effects of prior destructive behavior, anonymity, and group presence on deindividuation and aggression

Abstract

Manipulated 3 of P. G. Zimbardo's (1969) deindividuation input variables (group presence, anonymity, and arousal) in a laboratory experiment with 80 male undergraduates to study their effects on aggression and deindividuation. Only arousal produced a significant increase in aggression, while group presence produced a significant decrease in aggression. Anonymity had no significant effect on Ss' aggressiveness. Deindividuation per se was measured on a postsession qestionnaire that assessed Ss' memory for their own aggressive behavior, self-consciousness, concern for social evaluation, and memory for central and peripheral cues. Only arousal condition participants showed deindividuation changes, but a factor analysis revealed that the deindividuation changes did not comprise a unified factor. Also it did not appear that the internal changes caused aggressive behavior, since the correlation between the 2 variables was low. (15 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1976 American Psychological Association.