Alcohol and Aggression: Pharmacological versus Expectancy Effects

Abstract

An expectancy hypothesis has been put forward to explain the relationship between alcohol intoxication and aggressive behavior. An experiment tested this hypothesis using a balanced placebo design. The experiment was performed within a modified version of the Buss “shock-machine” procedure. Subjects were randomly assigned to either an alcohol-drinking group or a tonic-drinking group. Each group was further subdivided into one informed that the drink contained alcohol and one informed that the drink contained only tonic. Subjects' expectancies concerning the effects of alcohol on aggression were actively manipulated. Aggressive behavior was measured both in an absolute and a relative way. Given difficulties with the procedural deception about the drink, it was not possible to evaluate pure pharmacological effects. Results did not support an expectancy interpretation in that the two alcohol-drinking groups were more aggressive than the two tonic-drinking groups. Results were discussed in terms of methodology explaining the difference in results between the present study and a similar study by Lang, et al. in 1975.