Six experiments used magazine approach in rat subjects to explore changes with time in responding for stimuli brought to a common moderate level of performance through acquisition or extinction. They found no evidence for increases with time in behavior during stimuli given simple acquisition. However, stimuli brought to that same level by reversal learning, repeated reversal, or partial reinforcement all showed increases in responding with time. These results suggest that the decremental process established by nonreinforcement endures through subsequent reinforcement and is especially sensitive to the passage of time.