Pursuing the Pavlovian Contributions to Induction in Rats Responding for 1% Sucrose Reinforcement

Abstract

The present study investigated whether Pavlovian conditioning contributes, in the form of the response operandum serving as a conditioned stimulus, to the increase in the rate of response for 1% liquid-sucrose reinforcement when food-pellet reinforcement is upcoming. Rats were exposed to conditions in which sign tracking for 1% sucrose was measured when a subsequent period would or would not provide food pellets. Upcoming food pellets produced an increase in the sign-tracking response, but several accounts could potentially explain that increase. In a second experiment, rats responded at a higher rate for 1% sucrose on a lever predictive of upcoming food pellets than on a lever reliably followed by nonreinforcement. A similar result occurred in concurrent-choice probe sessions. These results, consistent with those of the first experiment, cannot be accounted for by the same alternative explanations and therefore suggest that Pavlovian conditioning can contribute to the observance of positive induction.