Kids lie early, often, and for all sorts of reasons—to avoid punishment, to bond with friends, to gain a sense of control. But now there’s a singular theory for one way this habit develops: They are just copying their parents.

In the last few years, a handful of intrepid scholars have decided it’s time to try to understand why kids lie. For a study to assess the extent of teenage dissembling, Dr. Nancy Darling, then at Penn State University, recruited a special research team of a dozen undergraduate students, all under the age of 21. Using gift certificates for free CDs as bait, Darling’s Mod Squad persuaded high-school students to spend a few hours with them in the local pizzeria.

Each student was handed a deck of 36 cards, and each card in this deck listed a topic teens sometimes lie about to their parents. Over a slice and a Coke, the teen and two researchers worked through the deck, learning what things the kid was lying to his parents about, and why.

“They began the interviews saying that parents give you everything and yes, you should tell them everything,” Darling observes. By the end of the interview, the kids saw for the first time how much they were lying and how many of the family’s rules they had broken. Darling says 98 percent of the teens reported lying to their parents.

Out of the 36 topics, the average teen was lying to his parents about twelve of them. The teens lied about what they spent their allowances on, and whether they’d started dating, and what clothes they put on away from the house. They lied about what movie they went to, and whom they went with. They lied about alcohol and drug use, and they lied about whether they were hanging out with friends their parents disapproved of. They lied about how they spent their afternoons while their parents were at work. They lied about whether chaperones were in attendance at a party or whether they rode in cars driven by drunken teens.

Being an honors student didn’t change these numbers by much; nor did being an overscheduled kid. No kid, apparently, was too busy to break a few rules. And lest you wonder if these numbers apply only to teens in State College, Pennsylvania, the teens in Darling’s sample were compared to national averages on a bevy of statistics, from academics to extracurriculars. “We had a very normal, representative sample,” Darling says.

For two decades, parents have rated “honesty” as the trait they most wanted in their children. Other traits, such as confidence or good judgment, don’t even come close. On paper, the kids are getting this message. In surveys, 98 percent said that trust and honesty were essential in a personal relationship. Depending on their ages, 96 to 98 percent said lying is morally wrong.

So when do the 98 percent who think lying is wrong become the 98 percent who lie?

It starts very young. Indeed, bright kids—those who do better on other academic indicators—are able to start lying at 2 or 3. “Lying is related to intelligence,” explains Dr. Victoria Talwar, an assistant professor at Montreal’s McGill University and a leading expert on children’s lying behavior.

Although we think of truthfulness as a young child’s paramount virtue, it turns out that lying is the more advanced skill. A child who is going to lie must recognize the truth, intellectually conceive of an alternate reality, and be able to convincingly sell that new reality to someone else. Therefore, lying demands both advanced cognitive development and social skills that honesty simply doesn’t require. “It’s a developmental milestone,” Talwar has concluded.

This puts parents in the position of being either damned or blessed, depending on how they choose to look at it. If your 4-year-old is a good liar, it’s a strong sign she’s got brains. And it’s the smart, savvy kid who’s most at risk of becoming a habitual liar.

Continue reading the New York Magazine article by Po Bronson: here.