A few weeks ago, as part of his normal evening ritual, my almost 3-year-old son used the potty, brushed his teeth, and climbed into bed. As we were saying our night-nights, he interjected: “Mommy, I need to use the potty.” It had been about six minutes since he’d gone. I suspected he was trying out a new bedtime stall tactic, but I couldn’t not let him try. He sat on the potty. We waited. Then: “I don’t need to go.”
I had just caught my son in a lie—the first I’d ever noticed. The next night, it was the same thing all over again. I had no idea what to do.
So I started reading the research on childhood lying. Turns out there’s a lot of it, because by studying how and when children lie, psychologists can glean new insights into psychological development. I, of course, was more interested in the practical applications: How do I keep my kid from turning into a sociopath? Dozens of research papers and several phone calls later, I’ve learned that not only is lying completely normal in kids, it’s actually a sign of healthy development. And yes, there are things parents can do to foster honesty in their kids—things that I haven’t been getting exactly right.
If your kid has been lying, “that’s very, very normal,” explains Kang Lee, a developmental psychologist at the University of Toronto who has been studying lying in children for 20 years. Generally, kids start to lie by around the age of 2½ or 3, usually to cover up transgressions. In a classic 1989 study, researchers at the University of Medicine and Dentistry of New Jersey took individual 3-year-olds into a room equipped with a hidden video camera and a one-way mirror and sat them facing away from a table. The researchers told the children they were going to put a surprise toy on the table and instructed the kids not to look at it. Then the researchers left the room. They returned either once the children had peeked at the toy (most did) or after five minutes had passed, and asked the kids whether they had looked. A whooping 38 percent of the kids who had snuck a peek lied, assuring the researchers that they hadn’t seen the toy. In a similarly designed 2002 study co-authored by Lee, 54 percent of 3-year-olds lied about peeking, whereas more than three-quarters of kids aged 4 to 7 did.
When kids lie, it’s not a sign that they’re on the road to delinquency—it’s a sign that they are developing important psychological skills. One is “theory of mind,” the ability to recognize that other people can have different beliefs or feelings from you. In order to lie, your child has to realize that although he knows full well that he broke your vase, you do not. Lying also requires “executive function,” a complex set of skills that includes working memory, inhibitory control, and planning capabilities. Your kid has to hide the truth, plan up an alternate reality, tell you about it, and remember it. Good job, kid!
So kids who lie are demonstrating important cognitive skills. But paradoxically, they also lie in part because they don’t have great cognitive skills. As I’ve written about before, children are emotional and impulsive—they struggle a lot with inhibitory control, one aspect of executive function—which is why, despite your clear instructions not to, they will continue to use their forks as drumsticks and hit their siblings. Then, to cover up their mistakes, they’ll lie to avoid getting punished. In other words, kids lie a lot in part because they can’t help but defy you a lot, and they don’t want to suffer the consequences. Can you blame them?
One easy thing we can do to keep our kids from lying is to avoid setting them up to do so. If you know full well Nathan ate the last cookie, you don’t need to challenge him with Nathan, did you eat the last cookie? That’s just asking him to fib—he can sense trouble is just around the corner, and he wants more than anything to avoid it. Instead, say something like, “I know you ate the last cookie, and now you're not going to have room for dinner, and unfortunately the consequence is going to be that you have no cookies tomorrow,” suggests Angela Crossman, a developmental psychologist at CUNY’s John Jay College of Criminal Justice. (If you do desperately need to extract the truth out of your child, ask him beforehand to promise you that he will tell you the truth. It may sound silly, but it helps: One study found that 3- to 7-year olds were 16 percent less likely to lie after promising to be honest. Suckers.)
Another thing you should absolutely not do, Lee says, is to tell your child that you won’t get mad at him if he tells you the truth, and then get mad at him for telling you the truth. Parents do this all the time, he says, and it teaches kids that truth-telling gets punished, that they’d be better off lying. “You really have to live up to your end of the bargain—if your child tells the truth, then you say ‘that’s great,’ and just ignore the bad behavior, regardless of how bad it is,” Lee says. (If you know you can’t follow through—for instance, if the transgression you’re asking about is really terrible—don’t make such a promise in the first place.)