Nothing seems kinder than telling a child they’re smart. In a poll Claudia Mueller and Carol Dweck cited, 85% of parents thought praising a child’s intelligence after a success was necessary to make the child feel smart.
Mueller and Dweck, psychologists at Columbia, decided to test it. Their studies, published in 1998, put fifth graders one at a time in an empty classroom with a researcher and a set of ten picture puzzles. After four minutes, every child heard the same thing: “Wow, you did very well on these problems,” then a number, then “That’s a really high score.” Every child was told they had solved at least 80%, whatever the real score.
Then the one sentence that differed. Some children heard “You must be smart at these problems.” Others heard “You must have worked hard at these problems.” A third group heard nothing more.
Before the next round, the children could choose what kind of problems to work on later. In the first study, 67% of the children praised for intelligence picked options like “problems that are pretty easy, so I’ll do well.” Of the children praised for effort, 92% picked “problems that I’ll learn a lot from, even if I won’t look so smart.”
Next came a much harder set, and the news that they had done “a lot worse.” Those praised for intelligence were now less willing to keep going. In one study, on a third set as easy as the first, their scores slipped below where they had started. The effort group’s went up.
In that same study, the researchers added a last step. Each child wrote a description of the puzzles for children they didn’t know, in another state, including how many they had solved.
Among children told they were smart, 38% reported a higher score than they had earned. Among children praised for effort, 13% did. Among children who had heard no extra praise, 14%. Every misreport went the same direction: up.
The study has had critics. In 2019, Yue Li and Timothy Bates tested 624 children aged ten to twelve and found that praise for intelligence had no significant effect on their performance.
At the end of each session, every child was told the hard puzzles had been meant for seventh graders, and that solving even one was quite an achievement. The researchers wrote that they took “extensive precautions” so that all of them left proud of their performance.