Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)




Study of the factors influencing the occurrence of aggression received impetus from the frustration-aggression hypothesis of 1939. It was hypothesized that aggression was the primary consequence of frustration, and that the stronger the frustration, the stronger the aggression. Numerous studies have shown that frustration can lead to aggression v/ith organisms ranging along the phylogenetic scale from rats to humans. While questionnaire studies have shown that the strength of aggression varies v/ith the strength of frustration, this has not been verified in laboratory studies of direct physical aggression.

Recently, the importance of situational variables, such as the perceived arbitrariness of the frustration, have been stressed. The influence of this variable also has not been verified in laboratory study of direct physical aggression.

V/hat happens after an aggressive act, influences the probability of future aggression. The instrumentality of aggression refers to the effectiveness of aggression in overcoming an obstacle to a goal. Instrumentality has been studied in the laboratory but not in the most effective manner.

Instrumentality of aggression and the strength and arbitrariness of frustration, in relation to direct physical aggression, were investigated by employing the "aggression machine" (Buss, 1961) in an ostensible learning task. The subjects, 120 male Introductory Psychology students, were required to teach a confederate a concept. Frustration consisted in the confederate's inability to learn the concept. The measure of aggression was the mean intensity of shock ostensibly administered to the confederate for incorrect responses. Different strengths of frustration were established by blocking at a point near the completion of the learning task and at another point more distant. There was a control group which was to experience no frustration. Instrumentality was established by reinforcement of high intensity shocks in the "warmup task" for those subjects in the instrumental condition but not for those in the noninstrumental condition. Arbitrariness was established through the instructions, which attempted to have the frustration viewed as arbitrary or nonarbitrary.

It was hypothesized that: the strength of aggression would increase with the strength of frustration; more aggression would occur under the arbitrary than under the nonarbitrary condition; more aggression would occur when aggression was instrumental than when it was noninstrumental; and the most aggression would occur when aggression was instrumental and frustration was strong and arbitrary.

The results of this study show that it was possible to establish different strengths of frustration on the basis of blocking near to or far from a goal. The stronger frustration produced more aggression than the v/eaker frustration but only when aggression was experienced as instrumental in overcoming frustration. Additional support for the frustration-aggression hypothesis was provided by ,the increase in aggression as the number of frustrations increased.

No more aggression occurred in the condition where frustration was intended to be viewed as arbitrary than in the condition where frustration was intended to be viewed as nonarbitrary. This was not interpreted as indicating that situational aggression eliciting stimuli, the arbitrariness of frustration in particular, are not important determinants of aggression. Rather, the wording of the instructions was viewed as a possible cause for the ineffectiveness of this variable.

The control group proved to be ineffective in this study. It was hypothesized that rather than being a control group, that this group, because of the schedule of the "victim's" responses, really was an additional frustration group. The results of the experiment were seen as providing some support for this hypothesis.