The effects of reinforcement schedules on the behavior of white rats in Skinner Box. II

The pattern of reinforcement schedules

Abstract

Using Skinner Box, we examined the differential effects of the number of reinforcement and the pattern of reinforcement schedule, with a fixed number of response, at a fixed series schedule, on the learning of bar-pressing by white rats with thirst and hunger drives. The findings from the results of training of fourty-nine rats divided into nine groups in texperiment 1 and fifty-two rats divided into ten groups in experiment 2 were :
1) In acquisition training, the performance of the groups trained by partial reinforcement schedule improved as the training proceeded.
The average response latency of each group approached specific asymptotes, which were higher for the groups with greater number of reinforcement. This finding is supported by mathematical model by Bush and Mosteller and the experimental findings by others. As to the effects of the pattern of reinforcement schedule on the average latency of each group, the group with greater size of the unit of the pattern of reinforcement schedule showed higher latency.
2) In extinction training, with fixed number of response in acquisition training, the resistance to extinction increased up to a certain point as the reinforcement ratio decreased, but with further decrease of reinforcement ratio it Started to decrease.
This maximal piont, the so-called optimal point, is influenced by at least three factors : the number of response in acquisition training, the size of the unit of the pattern of rein-forcement schedule, and the criterion of the resistance to extinction we adopt.
However, as MacKintosh suggested, by the inspection of the behavior of rats in extinction training, the resistance to extinction did not appear to be the only index of habit strength or the strength of response tendency, and we tentatively discussed this problem from the point of view of frustration theory.