Intrinsic vs. extrinsic motivation: why external rewards often backfire

Published by Motivational Team · Updated 2026-09-03

Money, likes, and praise feel motivating — until they don't. Research shows that the wrong kind of motivation can actually destroy your drive.

In one of psychology's most fascinating experiments, Edward Deci asked participants to solve puzzles. One group was paid per puzzle. The other wasn't. During a free-play period where participants could do anything, the unpaid group continued solving puzzles for fun. The paid group mostly stopped. Paying people to do something they already enjoyed actually reduced their motivation to do it. This counterintuitive finding launched decades of research into what psychologists call Self-Determination Theory (SDT), developed by Deci and Richard Ryan. Their work reveals a fundamental truth about human motivation that most reward systems get wrong. The two types of motivation: Extrinsic motivation: Driven by external rewards or punishments. Money, grades, likes, approval, fear of consequences. "I do this because of what I get." Intrinsic motivation: Driven by internal satisfaction. Interest, curiosity, enjoyment, meaning. "I do this because it matters to me." Both are real. Both can drive behavior. But they operate differently — and interact in surprising ways. The overjustification effect: When you introduce external rewards for an activity someone already enjoys, you shift their perception of why they're doing it. Before the reward: "I do this because I enjoy it." After the reward: "I do this because I'm paid for it." Remove the reward, and the original intrinsic motivation has been undermined. This is the "overjustification effect." A meta-analysis by Deci, Koestner, and Ryan examined 128 studies and confirmed: tangible rewards (money, prizes, tokens) consistently undermine intrinsic motivation for interesting tasks. The more controlling the reward ("you must complete X to receive Y"), the greater the damage. This doesn't mean all rewards are bad. Unexpected rewards, verbal p