The partial reinforcement extinction effect after treatment with chlordiazepoxide

Two experiments are reported, in which rats were run in a straight alley for food reward with or without injections of the anti-anxiety drug, chlordiazepoxide (CDP). The experiments were directed to two questions. (1) Can one predict the effects of CDP from knowledge of the effects of a second anti-anxiety drug, sodium amylobarbitone (SA)? (2) Can the effects of CDP be predicted from the hypothesis that anti-anxiety drugs attenuate responses to conditioned frustrative stimuli? The experiments examined the effects of CDP on the partial reinforcement extinction effect (PREE) at one trial a day. CDP injected throughout acquisition and extinction reduced the PREE. This effect was probably due to the presence of the drug during acquisition. Injected during extinction only, CDP increased resistance to extinction in both continuous and partial reinforcement groups. These effects of CDP were closely similar to those previously reported for SA, thus answering question (1) in the affirmative. The effects of CDP on the PREE were also consistent with the conditioned-frustration hypothesis (question 2).