Document Type



A series of recent studies have demonstrated that rats will increase their rate of operant responding for sucrose reinforcement when food-pellet reinforcement will be upcoming in the same session. One potential explanation for this increase is that operant, rather than respondent or general, behavior becomes increasingly probable in sessions in which food-pellet reinforcement will be available. This explanation implies that it is not necessarily upcoming food-pellet reinforcement that produces the induction. The present study investigated this implication by having rats press 1 lever (Experiment 1) or 3 different levers (Experiment 2) for 1 % liquid-sucrose reinforcers delivered by a 3-component multiple schedule. Across treatment conditions, food-pellet reinforcement replaced sucrose reinforcement in one of the three 15-min components. Doing so produced an induction effect in responding for sucrose in the other components. However, the size of induction did not differ depending on the temporal placement of the food-pellet reinforcement. These results are therefore consistent with the above, operant explanation.