Female subjects in this study were induced to harm another person in an alleged "learning" study by administering aversive noise to a confederate-victim as she performed a problem-solving task. The subjects consisted of forty-six female undergraduates enrolled in Introductory Psychology at the University of Toronto. They were randomly assigned to four experimental conditions comprising a 2 x 2 factorial design. Two hypotheses were initially entertained. First, choosing to agress may create greater personal responsibility for the aggressor than nonvoluntary aggression. The second hypothesis assumed that choice may primarily sensitize an aggressor to situational norms concerning aggression. If so, choice may curtail unprovoked aggression primarily when it is situationally defined as being socially undesirable. The results of this study clearly disconfirmed these initial hypotheses concerning the effects of choice upon aggression. In conclusion, this study suggested that in general, portraying harming another as being socially undesirable tends to inhibit the amount of unprovoked interpersonal aggression. (Author/BW)