Most famously, Dweck and her collaborators have demonstrated that praising children for their intelligence can backfire. When young people’s sense of self-worth is bound up in the idea that they are smart—a quality they come to understand as a genetic blessing from the sky—at least three bad things can happen. Some students become lazy, figuring that their smarts will bail them out in a pinch. Others conclude that the people who praise their intelligence are simply wrong, and decide that it isn’t worth investing effort in homework. Still others might care intensely about school but withdraw from difficult tasks or tie themselves in knots of perfectionism. (To understand this third group, think of the Puritans: They did not believe they had any control over whether they were among God’s elect, but they nonetheless searched endlessly for ways to display that they had been chosen, and they were terrified of any evidence that they were not.)

It is much wiser, Dweck says, to praise children for work and persistence. People nearly always perform better if they focus on things they can control, such as their effort, rather than things they cannot.