Effects of caffeine on human aggressive behavior.

A new methodology was employed to study the effects of caffeine on human aggressive behavior in a laboratory situation. Aggressive responding was elicited by subtracting money from the research subjects, which was attributed to a fictitious person. Caffeine compared to placebo produced decreases in two types of aggressive responses, but increased nonaggressive monetary reinforced responding. Thus, the suppressing effect of caffeine on aggressive responding was not due to a nonspecific depressant action.