SCHEDULE‐INDUCED LICKING DURING MULTIPLE SCHEDULES 1

Abstract

Schedule‐induced polydipsia was studied in rats bar pressing under two‐component multiple schedules of food reinforcement. The first component of the multiple schedule was a variable‐interval 1‐min schedule throughout the experiment. The schedule comprising the second component was varied over blocks of sessions in terms of rate and magnitude of reinforcement, and was either variable‐interval 3‐min (one pellet), variable‐interval 3‐min (three pellets), variable‐interval 1‐min (one pellet), or extinction. Water intake per session varied with the rate of reinforcement in the schedule comprising the second component and was highest when the schedule was variable‐interval 1‐min. Both bar‐pressing behavior and licking behavior showed behavioral interactions between the two components of the multiple schedules. With magnitude of reinforcement held constant, a matching relationship was observed between lick rate and reinforcement rate; the relative frequency of licks in the constant component matched the relative frequency of reinforcement in that component. Bar pressing, however, showed only a moderate degree of relativity matching. During the schedule‐induced licking, a burst of licking followed each delivery of a pellet (post‐prandial drinking). The duration of these bursts of licking was observed to be a function of the inter‐reinforcement interval.