What happens when a child cleans a room only because a sticker, dessert, or extra screen time is waiting? The task gets done, which can feel like a win on a busy evening, but the bigger lesson may be less obvious.
The Enlightenment philosopher warned that a child trained mainly through prizes and punishment may learn to calculate personal advantage instead of asking what is right.
Modern research does not prove that every reward is harmful, yet it supports a more careful conclusion. Rewards can produce quick compliance, while lasting motivation is more likely when children understand the reason, feel capable, and have some voice in what happens.
The original warning
The line appears in Lectures on Pedagogy, based on courses taught at the University of Königsberg and published in 1803 from notes arranged by Friedrich Theodor Rink.
The philosopher wrote that a child may “do right merely for the sake of the reward” and later choose right or wrong according to personal advantage. His concern was moral character, not whether a sticker chart can get pajamas put away before bedtime.
He argued that moral education should be built on “maxims.” In short, a maxim is a guiding rule that a person understands and accepts, such as telling the truth because trust matters. This fits his broader idea of autonomy, which means learning to act from reasons rather than being controlled only by fear, pressure, or a promised prize.
What modern research says
More than 190 years later, Edward Deci, Richard Koestner, and Richard Ryan reviewed 128 experiments on external rewards and intrinsic motivation. Intrinsic motivation is the urge to do something because it is interesting or satisfying in itself.
Their meta-analysis found that expected tangible rewards reduced, on average, how freely people returned to an interesting task after the reward disappeared, with tangible rewards tending to be more harmful for children than for college students.
That finding needs context, and the broader evidence is not limited to children. A later 40-year meta-analysis led by Christopher Cerasoli examined 183 samples involving more than 212,000 people across school, work, and physical activities.
Intrinsic motivation predicted the quality of performance more strongly, while incentives were better at predicting quantity, meaning rewards may help someone do more without necessarily helping them do better.
Feedback is not a prize
The message is not that adults should stop noticing good behavior. In a 2018 experiment, Elien Mabbe and colleagues at Ghent University asked 110 children, averaging about 11 years old, to work on puzzles under different feedback styles. Positive feedback delivered in an autonomy-supportive way produced the strongest interest and persistence.
“Autonomy-supportive” does not mean letting children make every rule. It means explaining the reason for a request, listening to their perspective, and avoiding language that feels needlessly controlling. A parent can still say the homework must be finished, but the conversation changes when the child is offered a choice about where to start and receives useful feedback on the strategy used.
Correction depends on delivery
Research on feedback cannot answer every question about punishment, but it shows why delivery matters. Carlton Fong and his co-authors reviewed 78 studies of negative feedback in children and adults.
On average, negative feedback did not reduce intrinsic motivation compared with neutral or no feedback, but it was less motivating than positive feedback.
The effect was less damaging when feedback explained how to improve, used clear standards, and was delivered face to face. That is a long way from humiliation, yelling, or a penalty unrelated to what happened. The point is correction, not revenge.
A practical approach
Rewards may still help when the immediate aim is short-term compliance or a routine that holds little natural interest.
A young child may use a simple chart while learning to brush their teeth every night, and a classroom may need clear consequences so everyone can learn. The risk grows when every helpful act, completed page, or kind gesture becomes a transaction.
In practical terms, adults can shift attention from the payoff to the reason. Instead of “You get candy because you shared,” they might say, “You noticed your brother was left out and made room for him.” Adults can also ask, “Why do you think that choice mattered?” and “What could you do differently next time?”
The deeper lesson
Children do not become self-directed all at once. External structure often comes first, but it should act like training wheels rather than the entire bicycle. Over time, the aim is to help a child connect behavior with responsibility, empathy, trust, and the effects their choices have on other people.
That is why the old warning still lands. The real question is not whether adults ever reward or correct a child, but whether those tools are building judgment or merely buying obedience.
The original passage was published in Lectures on Pedagogy, while the modern research discussed here was published in Psychological Bulletin, Educational Psychology Review, and the Journal of Experimental Child Psychology.
The main scientific review discussed in this article was published in Psychological Bulletin.
