The Partial Reinforcement Effect: Evidence from Continuous Trials

Abstract

Continuous trial studies of the PRE, and major hypotheses regarding its nature are reviewed. Three experiments are then reported. Experiment I compared four groups on resistance to extinction of a bar pressing response after 800 acquisition trials. In acquisition, Group I received CRF, Group II FR 10, and Groups III and IV received both CRF and FR 10 with distinctive stimuli associated with the two acquisition schedules. It was found that partial reinforcement produced a generalising effect; there was no evidence of stimulus control. Experiment II was identical to Experiment I except that acquisition was continued for 2900 trials. The generalising effect of partial reinforcement was again demonstrated, but there was evidence of stimulus control. In Experiment III, Group I received 6,000 trials on CRF, Group II 6,000 trials on FR 10, and Group III 60,000 trials on FR 10. All Ss were then extinguished under three conditions: the magazine operate stimulus was presented on CRF, on FR 10, or not at all and it was found that this stimulus is informative for Ss trained under partial reinforcement. A hypothesis derived from the Spence-Amsel position is advanced. This states that the PRE in both discrete and continuous trial situations is due to the conditioning of persistence through the process of counterconditioning cues signalling frustration to the instrumental response, and that in the continuous trial situation distinctive response modes corresponding to distinctive schedules of reinforcement are conditioned through the agency of the magazine operate stimulus. These response modes can be conditioned within the limits set by the influence of partial reinforcement, thus allowing for the development of stimulus control and subsequent differential performance in extinction for groups trained under partial reinforcement.