The effect of separate reinforced and nonreinforced exposures to a context participating in a Pavlovian discrimination procedure.

Rats were subjected to a Pavlovian discrimination procedure in which a target stimulus was followed by food in Context X and followed by nothing in a distinctively different Context Y. Two experiments sought to determine the effect of postacquisition manipulations regarding Context Y, on responding to the target in that context. In Experiment 1A, the effect of separate nonreinforced exposures to Context Y was examined and in Experiment 1B, the effect of a separate reinforced exposure was assessed in four groups of rats receiving different amounts of deliveries of the reinforcer in Context Y. It was found that both nonreinforced and reinforced exposures to Context Y had an adverse effect on the attenuation of responding to the target that was originally observed in that context at the end of discrimination training. The results were discussed in view of an occasion-setting account and of more traditional models of associative learning.