Precious Little Liars

In some ways, kids are a lot like their adult counterparts, only cuter. In other ways, they’re still figuring out what it means to be a person. That’s where developmental psychologists like Gail Heyman come in—she studies children’s cognitive development and how kids learn about the social world. Her recent interest? How children lie and cheat.

Working with colleagues in China and Canada, Heyman observed three-year-old children learning to lie. (Studies show we pick up the skill around that age.) Over 10 days, the children played a game where winning meant deceiving your opponent. As expected, in the beginning, most kids made no attempt to dupe others in order to earn treats. But by the end of the 10 days, some of the kids had become quite proficient deceivers.

It turns out that these same children also had the highest levels of two cognitive skills: theory of mind—understanding that others don’t necessarily know what you know—and cognitive control, or being able to keep from blurting out the truth.

In another study, Heyman and colleagues show that kids praised simply for being smart are more likely to cheat. The research builds on well-known work showing that praising a child’s innate ability instead of their particular effort has the unintended consequence of reducing their motivation to learn and lessened ability to deal with setbacks.

The findings by Heyman and her colleagues suggest there’s also a moral dimension to “You are so smart” vs “You did well that time,” and that the distinction matters at a much younger age than previously known. Even a three-year-old is sensitive to the subtle differences in praise.

In the study, children played a guessing game using number cards. When they guessed correctly, the kids were either praised for being smart or for their performance, while some got no praise at all. In the middle of the game, after getting the children to promise not to cheat, the researcher left the room. A hidden camera then recorded which kids got out of their seat or leaned over to peek at the numbers.

The kids who were praised for being smart were more likely to break their promise than the ones praised for how well they did or those who got no praise at all. Consequences were similar in a related experiment in which children were not directly praised for their smarts, but were merely told that they have a brainy reputation.

The reason, Heyman and her team believe, is that praising ability is tied to performance pressure in a way that praising behavior isn’t: Kids end up wanting to perform well in order to live up to others’ expectations, even if it means they need to cheat to do so.

The takeaways: Be choosy with how you praise a child. And the bright side of a kid fibbing to you? They’re acing theory of mind!