The overjustification effect occurs when an external reward reduces a person's intrinsic motivation to perform an activity they already enjoy. The reward becomes the perceived reason for participating, so motivation may decline when it is removed.
The Reasoning and Mechanism
In self-determination theory (SDT), intrinsic motivation depends on satisfying autonomy, competence, and relatedness. Overjustification primarily reduces autonomy.
An athlete may initially train because running is enjoyable and meaningful. If expected payment is then offered for every session, the perceived cause may shift from enjoyment to reward. This moves the athlete's perceived locus of causality from internal to external.
The mechanism is:
- The person initially participates for enjoyment.
- An expected external reward is introduced.
- The reward is interpreted as controlling behaviour.
- Perceived autonomy and intrinsic motivation decrease.
- After reward removal, participation may fall below its original level.
The outcome depends on how the reward is perceived:
| Reward situation | Likely effect | SDT explanation |
|---|---|---|
| Expected tangible reward for an enjoyable activity | May reduce intrinsic motivation | Experienced as controlling, reducing autonomy |
| Unexpected reward | Smaller or no effect | Behaviour was not initiated to obtain it |
| Positive feedback emphasizing improvement | May increase intrinsic motivation | Informational feedback supports competence |
| Reward for an uninteresting activity | May increase participation temporarily | Creates external motivation, not necessarily intrinsic motivation |
This distinction shows why reward type and interpretation matter more than reward alone.
A common misconception is that all rewards reduce motivation. Rewards are most likely to undermine intrinsic motivation when expected, tangible, and controlling; informational feedback can instead support competence.
Exam Technique
For an IB SEHS HL response, define the effect, link it to self-determination theory, and explain the causal chain from reward to reduced autonomy and intrinsic motivation. For an evaluate question, contrast controlling rewards with competence-supporting feedback and apply both to a sporting example.