The sticker that makes kids stop drawing
Promise a reward for something a child already loved doing, and a fifty-year-old experiment shows exactly what happens to that love next.
Researchers once let a group of children draw freely, then split them three ways. One group was promised a reward beforehand for drawing. A second group got the identical reward, but as a complete surprise afterward. A third got nothing.
Weeks later, only one group had lost interest in drawing on their own time: the kids who'd known the reward was coming. The surprise-reward group and the no-reward group kept drawing just as often as before, unaffected.
Psychologists call this the overjustification effect. Once you're doing something in order to get something else, your brain quietly downgrades the original reason you did it for free — the activity gets reclassified from "thing I love" to "thing I'm compensated for," and interest follows the reclassification down. The effect shows up with money, grades, praise, trophies, pizza parties for finishing books — the mechanism doesn't seem to care what the specific carrot is.
The strange part isn't that rewards fail. They work exactly as advertised, at exactly one thing: making people chase the reward instead of the reason they started.