SATIETY CONTRIBUTES LITTLE TO WITHIN-SESSION DECREASES IN RESPONDING

Responding often increases to a peak and then decreases within experimental sessions when subjects respond during operant conditioning procedures. The present experiments tested three implications of the idea that ''satiation'' produces the late-session decreases in responding. In Experiment 1, the late-session decreases were not altered when the caloric density of the reinforcer changed. In Experiment 2, the late-session decreases were not altered by changing the subject's state of deprivation, or the amount of food they were intubated with before the session. In Experiment 3, the late-session decreases were not alter ed by changing the size of the reinforcer by a factor of 3. The decreases began earlier and were steeper when reinforcers were 5 times as large. These results indicate that satiation, as operationalized in these experiments, does not cause the late session decreases in responding. Satiation may alter these decreases if large amounts of reinforcement are delivered. (C) 1995 Academic Press, Inc.