Pavlovian conditioned stimulus effects upon instrumental choice behavior are reinforcer specific

Abstract

In a transfer-of-control experiment with rats, Pavlovian CSs were tested for the specificity of their effects. The instrumental behavior consisted of a discriminative, conditional two-lever choice task in which qualitatively different appetitive reinforcers were contingent upon the two correct choices. In a Pavlovian phase, subjects experienced conditioning to establish either a CS + or CS − for one reinforcer or a CS + or CS − for the other reinforcer. Finally, in a test, these CSs were presented when there was the opportunity to make choice responses. The CS +s evoked choices of the lever which had eventuated in the reinforcer that had served as the Pavlovian US, while the CS −s showed only a slight tendency to evoke the other choice responses. When the CSs were compounded with the original S Ds, the CS +s had little effect upon the vigor of responding while the CS −s reduced the vigor of responding to the S D for the reinforcer that was the same as the US used in establishing the CS −. The results are discussed in terms of associative mediational theory and the reinforcer specificity of Pavlovian conditioned excitation and inhibition.