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Why Your Teenager Does Such Crazy Things

It’s not just raging hormones.

Adolescence is that time between the start of puberty and the acceptance of adult roles in society. In the developed world, this period of life usually ranges from around 13 to the early twenties. It’s a time when young people begin asserting their independence and forming their first deep attachments outside the family. And for many adolescents, it’s also a time for taking risks and exploring new experiences.

Many people blame raging hormones for teenagers’ reckless behavior, and no doubt that’s one reason. Testosterone, the hormone of sex drive, aggression, and risk-taking behavior, surges in the years after puberty. But not all teens drive fast, do crazy stunts on their roller blades, try out drugs, or engage in risky sex. So there must be other explanations.

Some scholars argue that adolescence is a manufactured phenomenon of Western society, a by-product of keeping our children dependent far longer than is natural or necessary. Because of the lengthy education required to become a productive member of modern society, most young people in the developed world don’t achieve complete independence until their mid-twenties. And since we don’t expect adult-like behavior from our teens, we don’t get it from them either.

This wasn’t always the case. Before the twentieth century, most people in the world got married, started a family, worked at their farm or craft, and generally acted as responsible adults during the period we now call “adolescence.” Life was short, and making a living was hard. Through most of history, the average person became a grandparent around the same age that quite a few dual-career couples today are just contemplating having their first (and probably only) child.

As with all issues in psychology, the question of adolescence comes down to nature and nurture. On the nature side, we point to hormonal changes and brain maturation. And on the nurture side, we point to societal expectations. No doubt, both factors are important.

It can also help to consider adolescence from an evolutionary perspective. Traits and behaviors that seem maladaptive in the present often served our ancestors well during the hundreds of thousands of years they lived on the African Savanna as hunters and gatherers. In a recent article, British psychologist Sarah-Jayne Blakemore argues that adolescence evolved as a developmental period in which young people build the social networks they’ll need to be successful adults.

In other words, the reckless behavior we associate with adolescence isn’t its key feature, but rather it's a product of peer-group influence. For instance, teens in an experiment in a driving simulator drove with a reasonable level of caution when alone in the car. But when they had a friend in the front passenger seat, they took far more risks at the wheel. Perhaps their buddy egged them on, or maybe they were just showing off.

Other research shows that teens take more risks, such as drinking alcohol or smoking marijuana, when they’re with their peers compared to when they’re alone. These results clearly indicate a social component to the risk-taking behavior we associate with the teenage years.

Incidentally, adolescent risk-taking isn’t a uniquely human feature. Mammals in general display more reckless behavior during the period between sexual maturation and their first sexual encounter. For example, adolescent male mice reared in a lab consume more alcohol when they’re with their peers compared to when they’re alone. In contrast, adult male mice (that is, those with sexual experience) moderate their alcohol consumption whether they’re “home alone” or “out with the guys.”

Adolescents, both mice and humans, are encouraged by their peers to take more risks. It could very well be that testosterone is the culprit here. Young males of many species engage in intrasexual competition for mates. Risk-taking—and risk-surviving—is how males establish their rank in the pecking order and demonstrate to the females that they’ve “got the goods.” And since males have to compete for mates, it’s no wonder that testosterone modulates both sexual and aggressive behavior.

But human adolescents aren’t just influenced by the presence of their peers. They’re also greatly concerned with what others in their age group think about them, even when they’re alone. In one study, children, adolescents, and young adults were asked to rate the risk of various scenarios. After they made each judgment, they were shown the rating that another person had supposedly made. This rating differed considerably from their own, and they were asked if they’d like to revise their initial judgment.

Both children and adults wanted to change their rating if they were told the other person was an adult, but not if the other person was a teenager. In other words, children and grown-ups trust the judgment of an adult over that of an adolescent. However, the teenagers’ behavior was the opposite. They changed their rating only if the other person was another teenager, but not if an adult. What do grown-ups know anyway? Clearly, this is the typical adolescent attitude.

Even brain activity is different in adolescents compared with adults. When teenagers were asked to perform various tasks while in an fMRI, areas of their brain that process social information were more active when they were told their peers would be monitoring their progress. Knowing that others were watching them had less effect on the brain activity of older adults.

Blakemore proposes that the key feature of adolescence is an increased desire to fit into a social network. If this is true, then many of the risky behaviors that teens engage in are likely due to peer pressure. She also points out that the high incidence of depression in adolescence seems to revolve around this strong need for social inclusion as well. After all, real or imagined exclusion from their peer group is a common complaint among teens suffering from mood disorders.

We may blame the ills of adolescence on peer pressure, but Blakemore points out that peer pressure can also be an instrument for bringing out the best in teenagers. She reports on several studies conducted in high schools in the United States and Great Britain. One involved an anti-bullying program, and another an anti-smoking campaign. When popular students in the schools were recruited to lead these campaigns, bullying and smoking behavior decreased substantially compared to those schools where adults led the campaigns. Likewise, more students volunteered for community service when it was seen as the popular thing to do.

Adolescence doesn’t have to be a time of storm and stress. In fact, many teenagers successfully channel their boundless energy and enthusiasm into athletics, music, and academics, and these efforts pay dividends long into their adult lives. If we grown-ups understand the overriding need they have for peer-group acceptance, we can arrange situations in which our teens thrive. It’s just that we’ve got to let them think it was all their idea.


Blakemore, S.-J. (2018). Avoiding social risk in adolescence. Current Directions in Psychological Science, 27, 116-122. DOI: 10.1177/0963721417738144

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