In Hans Christian Andersen's story, The Emperor's New Clothes, fraudsters sew the king a suit made of air but persuade his court that only the "unworthy" cannot see it. Although the king and his ministers harbor private concerns, all men fawn over the invisible threads to prove their own sophistication. The emperor dances down the street. His subjects—confused, weirded out, suspecting that everybody else "sees" a garment—enthusiastically play along. "How fine!" they shout. "What a perfect fit!" It takes a child, too young to understand this pageantry of decorum, to point out that emperor is marching down the street buck naked.

Social psychologists have a fancy term for this sort of shared delusion. It is pluralistic ignorance, technically defined as "the psychological state characterized by the belief that one’s private attitudes and judgments are different from those of others, even though one’s public behavior is identical.”

More simply: It's many people collectively praising a king's robes while privately seeing only a naked monarch. It's peer pressure dipped in irony.

The emperor's invisible threads are strewn across some of history's most shameful episodes. There is evidence, for example, that many Germans privately thought that Hitler was a barbarian, but they pretended to support his policies because they mistakenly assumed their views were unique. Historical accounts suggest that many white southern Americans in the early 20th century deplored Jim Crow laws, but they felt compelled to support them.

These examples suggest, rather frighteningly, that a group of people can engage in systematic bigotry, even when a majority of them are not actually bigots. That's not group-think, where people think and act the same way when they get together. Rather it's group-ignorance: people thinking one thing and doing another, because they are deluded about the majority's real views and then are conforming to that delusion.

Perhaps you're looking back up at the headline by this point and wondering what does all this have to do with high school?

In fact, what doesn't peer pressure conducted under a cloud of ignorance have to do with high school? To be a teenager is to be the subject of nearly universal misunderstanding. Teens appear as strangers to their own parents, as hormonal monsters on television, and as flighty naifs, with smartphones grafted to their palms, in the media. But it turns out that teens are just as hopeless at assessing themselves. A new study of high school behavior finds that young people wildly over-estimate the sex and drug life of their own classmates and even their own cliques.

Popular kids and male jocks aren't having nearly as much sex, or doing nearly as many drugs, as other high schoolers assume, said Geoff Cohen, a co-author and professor at Stanford University. "Teenagers grossly overestimate the amount of substance abuse of [pot heads] and the sex life of jocks," he said. "We knew there were stereotypes, but we were surprised by the level of caricature."

High schoolers assumed that jocks and popular kids drank more alcohol and had more sex than average students. But jocks' and popular teens' self-reported sexual behavior wasn't significantly different from the “brains” or the “others.” (The fact that kids vastly over-estimate popular men's self-reported sexual behavior is particularly interesting, because if men were going to lie about their own record, they would probably “lie up” to exaggerate their romantic successes.) The misconceptions didn’t always skew toward deviant behavior, either. Smart kids reported studying only about half as much as their classmates assumed.

"People thought the popular kids had lots of friends and the brains have no friends, but it turns that everybody had about the same number of friends," said Mitchell Prinstein, another co-author of the paper and a professor at the University of North Carolina at Chapel Hill. (The other co-authors included Sarah W. Helms, Sophia Choukas-Bradley, Laura Widman, and Matteo Giletta.)

Some of the most severe misperceptions—regarding popular kids' cigarette use and jocks' marijuana habits, for example—were within cliques and groupings. Indeed, not only do less-cool kids exaggerate the lifestyles of high school aristocracy, but also popular kids vastly overestimate the sex and drug behavior of other popular kids. An only-slightly-oversimplified summary of the survey might read: Everybody in high school thinks everybody else is having more sex and doing more drugs than they actually are.

So what if adolescents think their peers are kinkier than they actually are? Prinstein said perceptions about drug use—even misperceptions—can become reality.

"The number-one reason why adolescents engage in risky behaviors is peer influence,” he said. "Kids are influenced by their perception of what their peers are doing. But their perception is wrong!" The researchers showed that 9th graders with more exaggerated ideas of their popular peers' drug use were more likely to do drugs throughout high school. Other research by Prinstein and Cohen has showed that when you randomly assign kids in a laboratory setting to think that popular kids are deviants, they become more likely to endorse similar risky behavior.

I asked both professors if there was evidence that high schoolers would do less drugs if they knew about their peers' behavior, Is it enough to simply announce that the emperor has no clothes?

Changing misperceptions is a little more complicated than that, both authors said. "They’ve hung signs around college campuses that say how much students actually drink. But nobody believes those signs, because they think the adults who put them up are lying,” Prinstein said. "Or they’ll say, ‘That’s the average for the campus, but what’s the average for the cool kids?’"

What's more, adolescents readily gravitate to norms, and schools that publicize student drinking behavior might be accidentally endorsing drinking, Cohen said. "There is a checkered history to social norms marketing, like telling kids how much their peers actually drink on campus. What if the kids who don’t drink much at all say, ‘That’s more than I thought!’ Suddenly, they start drinking more.”

Cohen grabbed a medical metaphor to suggest a better way. In healthcare, he said, the value of "precision medicine” is to tailor treatments to individual people rather than treat a large population with one drug. The same should be done in social interventions, he said. The equivalent of “mass inoculation”—e.g.: hanging signs in school halls—could discourage some kids from risky stuff, but alert other students to the idea it’s normal to be a little bit bad. The precision-medicine approach would identify at-risk students with dangerously exaggerated impressions of drug use.

Personally, I've come away two big conclusions from reading this study and spending the last day talking to, and thinking about, its authors' comments.

1. We’re not so different … The fact that various cliques exaggerate one another's behavior suggests that high school students are more like each other than they think. Recall Prinstein's observation: "It turns that everybody had about the same number of friends." This is kind of a beautiful thought—that the jerks, jocks, jokers, and just normal kids from our high school were divided more by their grotesque misperceptions than by their actual behavioral differences. As the Breakfast Club kids write at the end of the movie, "Each one of us is a brain, and an athlete, and a basket case ... ” (or, as these results suggest, perhaps none of us is). As every villain in Hollywood history has intoned to a nemesis: “We’re not so different, you and I."

2. Bad weeds from good soil. We conform, not to the world as it exists, but to the world as we think it exists. It doesn't quite rise to the level of revelation that people often mimic other people. But the vicious cycle of pluralistic ignorance is that each individual in a group can privately understand that the group's public behavior is bad; yet nothing will change if each member considers her belief unique.

When each brother in a fraternity has qualms about rough hazing, yet they collectively force new member to over-drink—or, far worse, when families are bystanders to civil rights abuses, while privately condemning bigotry in their bedrooms—bad weeds grow from good soil. Even moral people can contribute to harmful norms. In high school and beyond, perhaps the best way to break the vicious cycle of pluralistic ignorance is to re-discover the bravery of Andersen's fictional child—and to call a naked emperor naked.