Reinforcer and response specificity in appetitive transfer of control

Three experiments examine transfer from appetitive Pavlovian conditioning to appetitive instrumental responding by varying the similarity between conditions of Pavlovian reinforcement and instrumental reward. After conditioning with rats confined in a restraining device, a CS for electrical stimulation of the brain (ESB) produced substantial facilitation of operant responding for ESB, while a CS for food facilitated operant responding for food. However, no effects on rate of responding for food were seen during a CS for ESB. In a fourth experiment, four groups of rats were trained to barpress for rewarding electrical stimulation of the brain (ESB) and then given discriminative Pavlovian conditioning with ESB. The groups differed in the degree of similarity between the stimulus-response sequences present during Pavlovian conditioning and those occurring in instrumental responding. As similarity increased, so did the degree of conditioned facilitation in subsequent transfer tests. These results indicate that conditioned incentive responses or reinforcer-derived expectancies are specific to the conditions under which they develop, rather than generalized emotional or motivational responses.