The Role of Response-Reward Correlation in Stimulus-Response Overshadowing

Some effects of combining reinforcers in operant training with mentally handicapped persons

Two experiments investigated the conventional practice of combining social and tangible rewards as a compound reinforcer in operant training procedures for mentally retarded persons. In the first experiment, there were no significant differences in acquisition of a color discrimination between subjects receiving combined social and food reinforcement and those receiving only one of the component reinforcers. In subsequent extinction, subjects who had received social reinforcement on its own responded more than combined reward subjects, who did not differ in extinction responding from food reward alone subjects. In the second study, higher rates of a simple manipulative response were established during training with food reinforcement alone and with combined reinforcement than with social reinforcement alone. Nevertheless, resistance to extinction was again superior after social reinforcement alone than after the food or combined reinforcement. This was the case despite generalization decrements from acquisition contingencies to extinction being kept to a minimum in this second study by the use of noncontingent reinforcement as the extinction procedure. Neither experiment, therefore, found any beneficial effects of combining the rewards, either in acquisition or in subsequent extinction.