The overjustification effect is what happens when offering someone a reward for doing something they already enjoy actually makes them less interested in doing it. Once the reward stops, they’re less motivated than they were before the reward was ever introduced. It’s one of the more counterintuitive findings in psychology: paying people for what they love can make them love it less.
How the Effect Works
The core idea is simple. When you enjoy an activity for its own sake, you explain your behavior to yourself in terms of genuine interest: “I do this because I like it.” But when someone starts paying you or giving you gold stars for the same activity, your internal explanation shifts: “I do this because of the reward.” The activity itself hasn’t changed, but your reason for doing it has. Psychologists call this a shift from intrinsic motivation (doing something because it’s inherently satisfying) to extrinsic motivation (doing something for an outside payoff).
The problem surfaces when the reward disappears. Without it, you no longer have the external reason to continue. And the original internal reason, the pure enjoyment, has been weakened by the shift in how you explain your own behavior. The result is that your engagement drops below where it started, before any reward was ever offered. By definition, the overjustification effect is confirmed when post-reward behavior is lower than pre-reward behavior.
The Classic Drawing Experiment
The most famous demonstration came from a 1973 field experiment with preschoolers aged three to five. Researchers first identified children who showed genuine interest in drawing with markers during free play. Then they split 51 of these kids into three groups.
In the first group, children were told upfront they’d receive a special certificate with a gold seal and ribbon if they drew. In the second group, children drew and then received the same certificate as a surprise, with no prior expectation. The third group neither expected nor received any reward. After the reward phase ended, researchers watched what the children did during free play, when no rewards were on the table. The children who had been promised the reward in advance spent significantly less time drawing than they had before the experiment. The other two groups showed no decline. The crucial difference wasn’t receiving a reward. It was expecting one. That expectation reframed the activity from play into work.
What the Broader Research Shows
A landmark meta-analysis published in 1999 reviewed 128 experiments on rewards and intrinsic motivation, confirming that the overjustification effect is real and consistent across studies. Tangible rewards that people expected beforehand reliably reduced intrinsic motivation. The size of the effect varied by the type of reward. Rewards given simply for engaging in an activity produced a moderate negative effect (d = -0.40), meaning a meaningful and measurable drop in interest. Rewards for completing a task and rewards tied to performance also undermined motivation, though slightly less.
The effect was stronger in children than in college students. This makes sense: children are still developing their sense of autonomy and are more susceptible to having their self-understanding reshaped by external incentives. Adults, with more established identities and interests, are somewhat more resistant, though not immune.
Why Verbal Praise Is Different
Not all rewards trigger the overjustification effect. The meta-analysis found that positive verbal feedback actually enhanced intrinsic motivation, with a moderate positive effect (d = 0.33) on voluntary engagement and a similar boost in self-reported interest. This is essentially the opposite of what happens with tangible rewards.
The difference comes down to what the reward communicates. A sticker or a cash bonus signals that the activity is a means to an end, something you do to get the payoff. Sincere praise, on the other hand, can reinforce your sense of competence and autonomy. When someone says “you’re really good at this,” it feeds back into the intrinsic loop: you feel more skilled, which makes the activity more enjoyable, which makes you want to do it more.
There are caveats, though. Praise that feels controlling (“good job, just like I told you to do it”) or that relies heavily on comparison to others (“you’re better than everyone else”) can backfire. The research suggests praise works best when it’s sincere, when it attributes success to the person’s effort or skill, and when it supports their sense of choice rather than obligation.
Everyday Examples
The overjustification effect shows up constantly in real life, often without anyone noticing. A child who reads for fun starts getting paid per book and eventually stops reading when the payments end. A hobbyist musician begins performing for money and finds that practicing feels like a chore once the gigs dry up. An employee who genuinely enjoys creative problem-solving gets put on a rigid bonus structure tied to output, and the work starts to feel mechanical.
It also appears in education. Reward systems like token economies, prize boxes, and achievement charts can boost short-term compliance, but they risk eroding the curiosity and enjoyment that drive long-term learning. A student who was naturally curious about science may come to see it as just another subject where you earn points.
When Rewards Don’t Backfire
The overjustification effect isn’t universal. Several conditions make it less likely to occur. If someone has no intrinsic interest in an activity to begin with, a reward can’t undermine what isn’t there. Paying someone to do tedious data entry won’t reduce their love for data entry, because there wasn’t any. In these cases, extrinsic rewards work exactly as intended.
Unexpected rewards also avoid the effect. In the drawing study, children who were surprised with a reward afterward showed no decline in interest. The key trigger is the expectation of reward before the activity, because that’s what reframes the mental explanation for doing it. If the reward arrives as a genuine surprise, it doesn’t change how you interpret your own motivation.
Rewards that provide useful information rather than control also tend to be safer. A reward that says “here’s how well you did” functions more like feedback than a bribe. The distinction matters: anything that supports your sense of choice and competence tends to preserve intrinsic motivation, while anything that makes you feel controlled or evaluated tends to erode it.
Practical Implications
If you manage people, teach, or parent, the takeaway isn’t that all rewards are bad. It’s that expected, tangible rewards for activities people already enjoy carry a specific and well-documented risk. The more someone already cares about what they’re doing, the more careful you should be about layering incentives on top of it.
When you do need to use rewards, keeping them unexpected, informational, and paired with genuine verbal acknowledgment of skill or effort reduces the chance of undermining the motivation you’re trying to support. And for activities where intrinsic motivation doesn’t exist yet, rewards remain a perfectly reasonable tool for getting people started, as long as there’s a plan for eventually letting the activity stand on its own.