CONDITIONED REINFORCEMENT FROM SHOCK TERMINATION.

Abstract

This study addressed the question of whether or not a stimulus paired with the termination of shock would acquire a positive conditioned reinforcing function. Previous investigators have suggested that a stimulus paired with shock termination must increase the frequency of a response upon which it is made contingent. This test for conditioned reinforcement is incomplete because multiple stimulus functions will be established during conditioning trials that can influence the rate of responding. The solution to this multiple stimulus control problem involved the effects of reinforcement upon events antecedent to the criterion response. Reinforcement results in the establishment of discriminative stimulus control. The test for conditioned reinforcement from shock termination, therefore, would involve using the presumed conditioned reinforcer to establish discriminative control for a response. Subjects were four male albino rats of the Wistar strain. The experimental procedure was divided into three phases. The initial phase involved consecutive trials in which a tone was paired with shock offset. The next phase continued tone/shock offset pairings and, in addition, the tone alone was presented sometimes for establishment of a lever press. In the third phase an attempt was made to bring the lever press under the discriminative stimulus control of a light. A successful response shaping effect was obtained for two of the four rats. There was no establishment of discriminative stimulus control for level pressing for the two rats who proceeded to the discrimination test for conditioned reinforcement. Conditioned reinforcement from shock termination was not revealed in this study. The establishment of stable discriminative control over the criterion response would require a strong reinforcer relative to the other established stimulus functions. Future research should concentrate on developing procedures to maximize the conditioned reinforcing properties while minimizing the control from competing stimulus functions.