Effects of d-amphetamine on human aggressive responding maintained by avoidance of provocation

Male subjects were administered placebo and three doses of d-amphetamine (5, 10 and 20 mg per 70 kg of body weight) under double-blind conditions in a laboratory setting which provided both aggressive and nonaggressive response options. The nonaggressive response was button pressing maintained by the presentation of points which were exchanged for money. The aggressive response was pressing another button which ostensibly resulted in the subtraction of points from a fictitious person. Aggressive responding was initiated by subtracting points from the subject. Point subtractions were attributed to the other person. Aggressive responding was maintained by an avoidance contingency between aggressive responses and scheduled provoking point subtraction presentations. d-Amphetamine increased nonaggressive responding, while aggressive responding was increased at the 10 mg dose and 20 mg resulted in significant decreases in aggressive responding relative to the 10 mg dose. Comparisons with previous research indicate that the contingency relationship between aggressive responses and presentation of provoking point subtractions can alter the effects of d-amphetamine on aggressive responding.