Common sense says: Want someone to do something more? Reward them!
But psychology reveals a dark side: external rewards can destroy internal motivation.
A person's intrinsic interest in an activity may be decreased by inducing them to engage in that activity as an explicit means to some extrinsic goal.
— Lepper, Greene & Nisbett, 1973
In 1973, researchers conducted a famous experiment at a nursery school. They found children who loved drawing—and then did something that would change how we think about motivation forever.
The 1973 Nursery School Experiment
1. Baseline
2. Intervention
3. Two Weeks Later
Observing Children's Free Play...
Expected Reward
👧🧒👦
🏆
Time spent drawing
Unexpected Reward
👧🧒👦
🏆
Time spent drawing
No Reward
👧🧒👦
—
Time spent drawing
All children showed natural interest in drawing with felt-tip markers during initial observation.
📊The Shocking Results
Two weeks after the rewards stopped, researchers observed free play again:
Before Rewards
16.7%
of free time spent drawing (baseline interest)
After Expected Rewards
8.6%
of free time spent drawing (50% reduction!)
The paradox: Children who were promised rewards became less interested in drawing than they were before the study began! Meanwhile, children who received unexpected rewards or no rewards maintained their original interest.
🧠Why Does This Happen?
Self-Perception Theory
When we do something, we ask ourselves: "Why am I doing this?"
I'm drawing
→
Why?
→
Because I love it! ❤️
But when rewards are introduced:
I'm drawing
→
Why?
→
For the reward 🏆
The reward becomes the explanation for the behavior. When the reward disappears, so does the reason to act. The original intrinsic motivation has been overwritten.
Before: "I draw because it's fun!"
After: "I draw for trophies. No trophy? Why bother?"
🎯The Critical Distinction
Not all rewards are equally damaging. The key factors:
Most Damaging
Expected rewards — known in advance
Tangible rewards — money, prizes, grades
Contingent on doing — "If you do X, you get Y"
Controlling language — "You should," "You must"
Less Damaging
Unexpected rewards — surprises after the fact
Verbal praise — recognition without material reward
Competence feedback — "You're really good at this!"
Autonomy support — "Would you like to..."
Key insight: It's not rewards themselves that are harmful—it's rewards that feel controlling or shift the perceived reason for behavior from internal to external.
🌍Real-World Examples
📚
Paying Kids for Grades
Studies show paying for A's can decrease long-term academic motivation. The child learns to work for money, not knowledge.
🩸
Blood Donation
Titmuss (1970) found that paying for blood decreased donations. Altruism was replaced by a market transaction.
🎨
Hobbies Become Jobs
Many artists report losing passion when their hobby becomes monetized. "I used to love this—now it feels like work."
🏃
Fitness Tracking
Some research suggests that gamified rewards (points, badges) can reduce exercise enjoyment over time.
👶
Toilet Training Rewards
Offering candy for potty success can backfire—children may refuse to go without the reward.
💼
Employee Bonuses
Deci's workplace studies found that performance bonuses can undermine intrinsic job satisfaction.
🛡️How to Motivate Without Destroying Motivation
Based on Deci & Ryan's Self-Determination Theory, support these three needs:
🎯
Autonomy
Give people choices and control. "How would you like to approach this?" not "Do it this way."
💪
Competence
Provide feedback that highlights skill growth. "You've really improved at X" builds lasting motivation.
🤝
Relatedness
Foster connection and belonging. People are more motivated when they feel part of something meaningful.
People are most motivated when they feel a sense of agency and control over their actions. By allowing individuals to have a say in setting their goals and choosing their own strategies, their intrinsic motivation can be preserved.
— Self-Determination Theory
📖The Tom Sawyer Principle
Mark Twain understood this long before the research:
Work consists of whatever a body is obliged to do, and play consists of whatever a body is not obliged to do.
— Mark Twain, "The Adventures of Tom Sawyer" (1876)
Tom got his friends to pay him for the privilege of whitewashing the fence—by making it seem like a rare opportunity rather than a chore. He understood that the framing of an activity determines whether it feels like work or play.
The overjustification effect is the reverse: turning play into work by adding external reasons to do it.