Summary
Five male undergraduates could earn 4¢ for every 200 knob-pulls. In addition, they could avoid or terminate an aversive tone by pressing a button with a force of 1.5 lbs (nonaggressive response) or by hitting a cushion with at least 20 lbs force (aggressive response). Rates of aggression tended to be higher during sessions where money was taken from the Ss at the rate of 1¢ per 12 seconds than during sessions when taking was not in effect. Rates of nonaggressive responses were constant across conditions.