The effect of intermittent reinforcement on the change in extinction rate following successive reconditionings.

Abstract

2 groups of 10 white rats each were strongly conditioned to make a bar-depressing response, one under conditions of continuous reinforcement and the other 50% reinforcement. Both groups were then extinguished, reconditioned, re-extinguished, etc., until there had been a total of 7 extinction periods. Animals trained under 50% reinforcement were found to be more resistant to extinction than those trained under 100% reinforcement on comparable extinction series. Both groups showed fewer trials to extinction with each successive extinction series. The change in rate of extinction with successive extinction series was significantly more rapid under conditions of continuous reinforcement. If only the first 5 min. of the extinction periods are analyzed, no change in rate of extinction is found for the 50% group. However, a change in rate was found to be statistically significant for the 100% group. These results are found in agreement with predictions from an extension of Hull''s theory.