PUNISHMENT OF SCHEDULE‐INDUCED DRINKING IN RATS BY SIGNALED AND UNSIGNALED DELAYS IN FOOD PRESENTATION

Abstract

Food‐deprived rats were exposed to a fixed‐time 60‐s schedule of food‐pellet presentation and developed schedule‐induced drinking. Using an ABA reversal design, three experiments investigated the effects of events then made dependent on licks. In Experiment 1, lick‐dependent signaled delays (10 s) in food presentation in general led to decreased drinking, which recovered when the signaled delays were discontinued. The drinking of yoked‐control rats, which received food at the same times as those exposed to the signaled‐delay contingency, showed much smaller changes. Experiment 2 showed that 10‐s lick‐dependent signals alone did not reduce drinking. In Experiment 3, when licks produced unsignaled 10‐s delays in food there were less marked and more gradual changes in drinking than in Experiment 1, although these effects again were greater than with yoked‐control animals. We concluded that both signaled and unsignaled delays functioned as punishers of drinking. These findings support the view that schedule‐induced drinking, like operant behavior, is subject to control by its consequences.