Overjustification

Overjustification is a psychological phenomenon in which external incentives or rewards undermine a person’s intrinsic motivation to perform a task that is already inherently interesting or enjoyable. The effect occurs when the introduction of rewards leads individuals to attribute their participation to the reward rather than to their own interest, reducing internal drive after the rewards are removed or no longer salient.

A classic demonstration came from Lepper, Greene, and Nisbett (1973) in which preschoolers who were rewarded for drawing later spent less time drawing than children who were not rewarded or were rewarded unpredictably. This finding supported the idea that extrinsic rewards can diminish intrinsic interest when the activity is already valued for its own sake.

The issue is explained within Self-Determination Theory, particularly through Cognitive Evaluation Theory. Intrinsic motivation depends on perceived autonomy, competence, and relatedness. Extrinsic rewards can undermine intrinsic motivation if they are perceived as controlling or if they convey that the task is performed for the reward rather than for personal interest. Rewards that are informational and autonomy-supportive, by contrast, may not undermine—and can sometimes support—intrinsic motivation.

The overjustification effect has implications for education, parenting, and workplace design. For tasks that people already find enjoyable, monetary or contingent rewards can backfire; for less inherently engaging tasks, external incentives may enhance persistence. Practical recommendations emphasize autonomy-supportive approaches, emphasis on mastery and interest, and careful consideration of how and when rewards are used.