IMMEDIATE POSTSESSION FEEDING REDUCES OPERANT RESPONDING IN RATS

Three experiments investigated the effects of immediate and delayed postsession feeding on progressive‐ratio and variable‐interval schedule performance in rats. During Experiments 1 and 2, immediate postsession feeding decreased the breakpoint, or largest completed ratio, under progressive‐ratio schedules. Experiment 3 was conducted to extend the results of the first two experiments to responding maintained by variable‐interval schedules with different session lengths (15 and 60 min). Response rates decreased in all 4 subjects when postsession feeding immediately followed a 15‐min session and in 3 of 4 subjects when postsession feeding immediately followed a 60‐min session. The implications of this research are twofold: (1) The functional context in which within‐session reinforcers are embedded extends outside the experimental chamber, and (2) supplemental postsession feedings should be sufficiently delayed from the end of a session to avoid weakening operant behavior in the experimental sessions.