Irrelevant Incentive Learning during Instrumental Conditioning: The Role of the Drive-Reinforcer and Response-Reinforcer Relationships

Four experiments investigated the processes by which a motivationally-induced change in the value of the training reinforcer affects instrumental performance. Initially, thirsty rats were trained to lever press for either a sodium or non-sodium solution. In Experiment I sodium-trained rats responded faster in extinction following the induction of a sodium appetite, but not following either food or water deprivation. Thus, enhanced extinction performance depends upon the relevance of the training reinforcer to the test drive state. The remaining experiments examined the role of the instrumental contingency. Animals received response-contingent presentations of one solution alternated either within (Experiments II and III) or between sessions (Experiment IV) with non-contingent presentations of another solution. Neither procedure yielded convincing evidence that contingent sodium presentations generated more responding in extinction under a sodium appetite than did non-contingent sodium presentations. On the basis of these results, we argue that the instrumental contingency itself does not play a major role in this irrelevant incentive effect.