Here is a finding that sounds impossible the first time you meet it. Take children who already love drawing, pay them to draw, then stop paying them — and they draw less than children who were never paid at all. Rewarding something can destroy the wish to do it.
📘 What you need to know
The overjustification effect: giving an external reward for an activity someone already enjoys can reduce their intrinsic motivation for it.
Lepper and colleagues (1973) studied nursery-age children at a Stanford University nursery who already enjoyed drawing.
Three conditions: reward expected, reward unexpected, and no reward.
Two weeks later, the children who had drawn for an expected reward spent less free time drawing than the other two groups.
The mechanism is a change in the child’s own explanation: “I draw because I like it” becomes “I draw to get the certificate”.
The unexpected-reward group was not harmed — which shows it is the deal that does the damage, not the reward itself.
The study, plainly
The researchers first found children who chose to draw when they had free time. That step matters: these children already had intrinsic motivation, so any change afterwards had to come from what the researchers did.
Over three weeks the children were placed in one of three conditions. Then the researchers went away and came back after a two-week gap, and simply watched how much the children drew when they could do whatever they liked. Free-choice time is a clever measure — nobody is asking the child anything, so there is no self-report bias to worry about.
Compare the first two cards carefully. Same certificate, same drawing, opposite outcome — so the damage came from the agreement, not the prize.
Why a reward can backfire
Children explain their own behaviour to themselves, just as adults do. Before the study, the explanation available to a child was simple: I draw because drawing is fun. Once a certificate is promised, a second explanation appears, and it is a louder one: I draw because I get something for it.
When the certificate stops, the loud explanation disappears — and the quiet one has been pushed aside. There is now no obvious reason to draw. The activity has been turned into work, and nobody works for free.
If a child hated drawing to begin with, there was no intrinsic motivation for the reward to displace. That is why the starting point of the study matters so much.
Notice how carefully you have to state this effect. Rewards do not always reduce motivation. They reduce it when the activity was already enjoyed and when the reward is expected in advance. Get those two conditions into your answer and you will sound like you understand the research rather than the headline.
What it means for learning
Schools run on expected rewards. Grades, merit points, prize-giving, certificates: every one of them is announced in advance and given for doing something the school wants. If the overjustification effect is real, the risk is obvious — a child who was curious about history can be trained into a student who works for the grade and stops the moment the grade stops mattering.
That does not mean rewards should be abolished. Rewards are useful for behaviours nobody enjoys, and for getting a reluctant learner started. The lesson is narrower and more practical: be careful about attaching prizes to the things a learner already loves.
The wider version of this idea shows up everywhere: the musician who stops enjoying music once it becomes a job, the athlete playing for sponsors, the creator who burns out once a hobby becomes income. A passion turned into a way of making money can stop feeling like a passion.
Worked example
WORKED EXAMPLE
To what extent are the findings of this study transferable to other populations or contexts? [6 marks]
Limit the sample first
Transferability is limited by the sample: nursery children at a university nursery attached to an elite institution. Their families are likely to be highly educated and comfortable, so they may not treat material rewards the way other families do.
Say what that means
The sample does not represent children from a wide range of socio-economic or educational backgrounds, so the size of the effect elsewhere is unknown.
Now argue for transfer
The mechanism is about how a person explains their own behaviour, not about nurseries. An external reward puts a price on something that was freely enjoyed, and that logic applies to education, sport and creative work alike.
Judgement
The principle transfers widely; the specific findings need replication in more varied samples before they are generalised.
Limits, then counter-argument, then a decisionNotice the shape: never only criticise. “To what extent” rewards the answer that argues both ways and then chooses.
💡 Exam tip
State both conditions for the effect: already enjoyed, and reward expected in advance.
Use the unexpected-reward condition. It is the control that proves the promise, not the prize, causes the drop.
Free-choice behaviour is a behavioural measure, not self-report — that is a genuine methodological strength worth a mark.
Apply it to school rewards. Real examples make an abstract effect concrete.
Keep the sample criticism short and precise. One well-explained limitation beats a list.
⚠ Common mix-up
“Rewards always reduce motivation.” Only under specific conditions. Say which.
Forgetting the children already enjoyed drawing. Without that, the effect makes no sense.
Confusing the two reward conditions. Expected reward is the one that caused the drop.
Calling this punishment. Nothing unpleasant happened. The reward was pleasant — that is what makes the finding interesting.
Only criticising the sample in a transferability question, without arguing what does transfer.
Up next: Strategies for Learning Independently — what students actually do when nobody is making them study, and how to pull apart the survey data that claims to measure learning styles.
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