SCHEDULES USING NOXIOUS STIMULI. II: LOW INTENSITY ELECTRIC SHOCK AS A DISCRIMINATIVE STIMULUS

Abstract

The presence or absence of pulses of low intensity electric shock was used as a discriminative stimulus to control responding under fixed ratio reinforcement in the squirrel monkey. Initially brief periods of non-reinforcement were lengthened only when discriminative control was evident. Discriminative control was studied by (1) varying the duration of non-reinforcement periods; (2) reversing the stimulus conditions correlated with reinforcement and non-reinforcement periods; and (3) determining the minimum shock intensity necessary to maintain discriminative control. Stimulus control was not reliably affected by d-amphetamine, chlorpromazine, or morphine. The discriminative control by pulses of low intensity electric shock was similar to that by other discriminative stimuli, except that the control developed slowly and was better when the pulsing shock was correlated with reinforcement than when correlated with non-reinforcement.