The goal of the proposed research is to expand our knowledge of the elementary learning processes of Pavlovian conditioning and instrumental training. These learning processes are fundamental not only to much of animal behavior but also to human normal and pathological functioning. Instrumental learning, which involves learning about the consequences of one's actions, is commonly conceptualized as having three component elements: a behavioral response (R), an outcome (O) of that response, and a stimulus (S) in the presence of which the response produces that outcome. Prior work from this and other laboratories has identified the development of associations among each of the pairs of these elements as contributing to behavior. Thus, organisms learn associations of the form R- O, S-O, and S-R, and each contributes to behavior. But they also acquire more hierarchical structures of the form S-(R- O), in which a stimulus activates an association between R and O. The development of the techniques of transfer and devaluation has allowed the separate measurement of these associations. The devaluation technique involves the changing of the value of an outcome after it has been earned by a response. Such devaluation of the outcome produces substantial and immediate depression of the value of both stimuli and responses that have led to that outcome, thus allowing measurement of both R-O and S-O associations. The transfer technique involves the ability of a stimulus trained with one behavior to transfer to the control of another behavior based on their sharing a common outcome. It therefore allows one to detect both the S-O and R-O association. Recent evidence suggests that these associations show amazing persistence even when they no longer accurately reflect the consequences of responding, as in extinction. The present research project will use the devaluation and transfer techniques, together with others to be developed, to measure the persistence of those a ssociations. It will explore the possibility that associations with goals persist but are suppressed by superimposed inhibitory associations not involving the outcomes. This research will also explore the fate of hierarchical associations. Similar procedures will also be applied to Pavlovian conditioning, which involves the learning of relations between two stimuli in the world. New results suggest that there, too, previously learned associations persist when conditions change. Moreover, there too hierarchical modulatory structures seem to contribute to performance. These studies will influence our thinking about elementary associative learning processes. They will particularly illuminate the process of extinction, a process important in many implications for understanding learning at the neural level.
