Effects of manipulation of S-O Contingency on the stimulus control of the discriminative stimulus in rats

Abstract

In the present study, we examined whether manipulating the association between discriminative stimulus and reinforcers, which is believed to be involved in the control of instrumental behavior, would affect the stimulus control of the discriminative stimulus. In Phase 1, subjects received instrumental training using discriminative stimulus X. In Phase 2, the contingency between the discriminative stimulus and the reinforcer was manipulated by pairing another stimulus Y (experimental group) or the discriminative stimulus X (control group) with the reinforcer. In the test, we predicted that the instrumental response to the presentation of stimulus X would be decreased in the experimental group, where the contingency of the discriminative stimulus X and the reinforcer was decreased. As a result, there was no difference in the discrimination rates of the two groups in the test, and the manipulation of the contingency of the discriminative stimulus and the reinforcer had no effect on stimulus control of the discriminative stimulus. The results of this experiment suggest that stimulus control by discriminative stimulus may be determined by a different structure (e.g., the relationship between response and reinforcer) from a direct association with the reinforcer.