Walk into almost any modern classroom, and you will spot them immediately: sticker charts pinned to corkboards, plastic bins labeled “Prize Box,” punch cards for good behavior, and promises of Friday pizza parties for reading logs.

For decades, behavioral economics and operant conditioning have dominated educational practice. The logic seems intuitive: If we want students to do something beneficial—read a novel, practice math facts, or help a peer—we should reward them for doing it.

In the immediate term, it works. The prize box commands attention; lines quiet down, and worksheets are handed in on time.

However, psychological research conducted over the past fifty years tells a sobering story. While tangible rewards reliably buy short-term compliance, they frequently do so by cannibalizing the most critical engine of lifelong learning: intrinsic motivation.

When we rely on carrots and sticks, we inadvertently teach children that learning is merely an unpleasant toll they must pay to reach a prize.

The Overjustification Effect: How Rewards Erode Curiosity

To understand why rewards backfire, we have to look at how the human brain interprets incentives.

In 1973, researchers Mark Lepper, David Greene, and Richard Nisbett conducted a landmark study with preschoolers who showed a natural, spontaneous interest in drawing. The researchers divided the children into three groups:

1. Expected Reward: Children were told upfront that if they drew with markers, they would receive a special “Good Player Award” certificate with a gold seal and ribbon.

2. Unexpected Reward: Children were given the opportunity to draw, and afterward, received the certificate as a spontaneous surprise.

3. No Reward: Children simply drew with markers, receiving nothing extra.

Two weeks later, the researchers observed the children during unstructured free-play time. The results were striking: the children who had received an expected reward spent half as much time drawing as they had before the experiment. The other two groups showed no decline in interest.

This phenomenon is known as the Overjustification Effect. When an external reward is introduced for an activity someone already finds interesting, the brain subconsciously shifts its perceived locus of causality from the inside to the outside

“I used to draw because I liked it. But now that someone gives me a certificate for it, I must only be doing it for the certificate.”

When the certificate disappears, the desire to draw disappears with it.

What the Meta-Analyses Reveal

This is not an isolated finding or an anomaly confined to early childhood. It has been validated across thousands of participants of all ages.

In 1999, Edward Deci, Richard Koestner, and Richard Ryan published a definitive meta-analysis examining 128 controlled laboratory experiments across three decades. Their findings confirmed that:

 Tangible, expected rewards substantially undermine intrinsic motivation for interesting tasks (d = -0.34).

 Task-contingent rewards (given simply for engaging in or completing a task) systematically degraded intrinsic drive (d = -0.40).

 Performance-contingent rewards (given for hitting a specific score or standard) still produced a significant negative effect (d = -0.28). Even though a good score conveys competence, the controlling, pressurized nature of the reward cancels out the positive feeling of mastery.

 Unexpected rewards had no detrimental effect, because students could not change their baseline behavior in pursuit of an unknown prize.

 Positive verbal feedback (informative praise) enhanced intrinsic motivation, provided it was not framed in a controlling manner.

Decades later, in 2014, Cerasoli, Nicklin, and Ford conducted another extensive meta-analysis spanning both classrooms and workplaces. They discovered that while extrinsic rewards can influence quantitative output (speed, memorization, basic rule adherence), intrinsic motivation is the primary predictor of qualitative performance—deep conceptual understanding, creative divergence, and complex problem-solving.

When we use prizes to manipulate academic engagement, we trade depth for speed.

3 Hidden Dangers of Classroom Reward Systems

Beyond dampening curiosity, relying on reward systems introduces three specific pedagogical problems:

1. It Encourages Intellectual Risk-Aversion

When a prize is on the line, students naturally seek the shortest, safest path to secure it. If a child earns a sticker for every book read, they stop choosing challenging, horizon-expanding literature and start hunting for the thinnest graphic novels or books well below their reading level. The goal ceases to be growth; it becomes clearing the hurdle.

2. It Crowds Out Prosocial Behavior

When students are rewarded with “Caught Being Good” tokens or raffle tickets for helping a classmate pick up dropped pencils, it reframes moral and communal behavior as a market exchange. Research by Uri Gneezy and Aldo Rustichini shows that once a behavior is commodified, students become far less likely to act altruistically when the reward currency is absent.

3. It Deepens Inequality and Frustration

Reward systems frequently punish the very students who need the most support. In a system where rewards are contingent on performance or compliance, neurodivergent students, students experiencing trauma, or those with executive functioning difficulties watch their peers pile up tokens while their own jars remain empty. This generates learned helplessness, resentment, and disengagement.

Moving Forward: 5 Actionable Shifts for the Classroom

Dismantling a reward system does not mean abandoning structure or high expectations. It means anchoring motivation in Self-Determination Theory (SDT), which demonstrates that intrinsic motivation thrives when three universal psychological needs are met: Autonomy, Competence, and Relatedness.

Here is how educators can make the shift:

1. Shift from Controlling Praise to Informational Feedback

Praise is often used as a verbal sticker: “Good boy!” or “I love how quiet Table 3 is!” This language is manipulative and teacher-centric.

 Instead: Provide clear, informational feedback focused on the process and competence.

 Example: Replace “I love how clean your desk is; take a star!” with “You organized your math folders by topic today. Notice how much faster you were able to find your compass?”

2. Introduce Meaningful Autonomy (Voice and Choice)

Students do not need incentives to care about work when they have agency over how they demonstrate learning.

 In Practice: Offer menus of demonstration. Instead of requiring every student to write a three-paragraph summary for points, allow them to choose between writing a review, staging an interview between historical figures, or annotating a visual diagram.

 Tip: Even tiny elements of choice—such as deciding the order in which they complete assignments or picking their work spot—dramatically reduce behavioral friction.

3. Establish Rationales for Low-Interest Tasks

Not every task in school is naturally fascinating; long division and phonics drills can be tedious. But instead of bribing students to complete them, explain the why.

 In Practice: Acknowledge their perspective honestly: “This set of drills is repetitive, and it takes focus. We are doing it because mastering this step makes solving full balance equations next week feel much easier.” Acknowledging difficulty while explaining utility protects a student’s internal sense of purpose.

4. Normalize the “Now-That” Over the “If-Then” Reward

Avoid “If-Then” incentives (“If everyone scores an 80% on this quiz, then we will have free time on Friday”). This makes the quiz feel like an obstacle course.

 In Practice: Use spontaneous, retrospective celebration (“Now-That”). If the class finishes a demanding group project with high engagement, say: “You all tackled that revision with incredible perseverance today. Let’s head outside for fifteen minutes of open courtyard time to celebrate how hard you pushed your thinking.”

5. Cultivate a Culture of Shared Contribution (Relatedness)

Replace individual reward jars with opportunities for collective contribution. When students feel their presence matters to the classroom community, compliance stops being a contest.

 In Practice: Involve students in co-creating classroom norms. Rather than handing down rules with associated penalties and rewards, ask: “What kind of environment do we all need to do our best thinking, and how can we support each other in maintaining it?”

Recommended Further Reading

If you want to dive deeper into the empirical literature on motivation and learning, explore these foundational texts:

1. Punished by Rewards: The Trouble with Gold Stars, Incentive Plans, A’s, Praise, and Other Bribes by Alfie Kohn

The classic, meticulously researched critique of educational and organizational behaviorism.

2. Drive: The Surprising Truth About What Motivates Us by Daniel H. Pink

An accessible synthesis of behavioral psychology distinguishing between algorithmic tasks and creative, heuristic problem-solving.

3. Self-Determination Theory: Basic Psychological Needs in Motivation, Development, and Wellness by Richard M. Ryan and Edward L. Deci

The primary academic text detailing decades of clinical and empirical research behind autonomy, competence, and relatedness.

4. The Overjustification Effect: A Meta-Analysis by Edward L. Deci, Richard Koestner, and Richard M. Ryan (Psychological Bulletin, 1999)

The definitive 128-study meta-analysis assessing the impact of extrinsic rewards on intrinsic motivation.