>Don’t blame the hormones
>Teen versus adult thinking
>Helping them learn

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Brain researchers are learning that teens often don't know exactly why they do dumb things, and hormones alone can’t take the rap for death-defying stunts or melodramatic scenes.

When Bryan Danielsen of Woodhull, N.Y., discovered his then-16-year-old son had a newly pierced nipple, he flipped. “I demanded to know who had done this to a minor and found out he had done it to himself with a needle,” Danielsen says. “But he told me not to worry, he was keeping it clean with alcohol — a bottle of white wine we had in the refrigerator.”

Why is it that when children hit puberty, even the most sensible ones suddenly start doing things to which the only possible response is, “What were you thinking?” And, even more infuriating, why is it that the reply you’ll often get to this exasperated question is a blank stare?

Parents, that blank stare isn’t just to make you crazy. Brain researchers are learning that teens often don’t know exactly why they do dumb things. Really.

Don’t blame the hormones

In the past, cockamamie teenage behavior and emotional storms were blamed solely on raging hormones. Today, as brain research grows more sophisticated, researchers say that hormones alone can’t take the rap for self-pierced nipples, death-defying stunts, melodramatic scenes, and other terrifying and infuriating adolescent behaviors.

“Hormones play a crucial role, but it’s more complicated than the image people had 50 years ago,” says Dr. Ronald Dahl, director of the Child and Adolescent Sleep and Neurobehavioral Laboratory at the University of Pittsburgh. “We find that a lot of kids with high hormone levels have no emotional problems at all.” Rather, Dahl says, teen behavior is a complex interaction between hormones, emotional changes, and brain development.

By brain development, researchers refer to actual physical changes in the brain. Humans are born with an enormous number of neural synapses in our brains — far more than are necessary for optimal functioning. Over time, some neural connections are strengthened, and others are pruned away. “This is a fundamental part of having an efficient brain,” Dahl says. “If you had a hundred rural country roads, that sort of works OK. But you want to get a couple of superhighways to carry most of the traffic.”

The neural strengthening is highway construction; the pruning is eliminating superfluous country lanes. (Currently, researchers aren’t sure how much of this process in individual brains is hard-wired and how much is a result of experience and learning.)

Teen versus adult thinking

One of the most compelling discoveries about the teen brain is that the connections between the emotional centers, such as the amygdala, and the decision-making centers in the prefrontal cortex are still being developed and refined. The ability to use rational thinking to override strong emotions is therefore less reliable in adolescence. When neuropsychologist Deborah Yurgelun-Todd of McLean Hospital in Belmont, Mass., hooked people up to an MRI machine, which measures brain activity, and showed them photographs of people’s faces, she found that adults and teens used different parts of the brain to interpret the emotion depicted. Adults used more of the prefrontal cortex to interpret the face, while teens’ emotional regions lit up during the task. Although adults correctly identified all the facial expressions as “fear,” only about half the teens did. The other half labeled the expressions as “shock,” “sadness,” or “confusion.” Remember this the next time you send what you think is a perfectly innocent glance at your teen and it triggers a scene.

In adolescents, the brain’s red-hot emotional centers can more easily overwhelm the less-developed input from the prefrontal voice of reason, leading smart teens occasionally to make dumb choices. “We think that part of the precariousness of decisions is the rate at which strong emotion and arousal can hijack decision making,” says Dahl.

In other words, environment can change a teen’s choices. Researchers find that in “cool cognition” situations — times of low arousal and emotions — teenagers are capable of sensible, adult decisions. Thus, when you sit your teens down at the kitchen table for levelheaded discussions about, for example, drunk driving, they are perfectly cognizant of the dangers and respond with appropriate tactics for avoiding risky situations. But in “hot cognition” situations — when they’re all worked up around their peers — the emotional center of their brains (Girls! Boys! Cars! Party!) hijacks the decision-making center (He’s had three beers…), and dumb things can happen.

“They’re just developing these higher-level skills, so the rush of strong feelings can flood it,” says Dahl. When they’ve been under the influence of all that emotional input from areas such as the amygdala, teens truly can’t explain later what they were thinking, because they weren’t really thinking. They were feeling.

Helping them learn

The influence of peers often heats up a situation, but don’t lock up the kids yet. It appears that being overly protective also can be a problem. Teens must have some opportunities to explore and test their limits with peers to develop self-control. It is as if the brain “uses” some of these experiences to refine the connections across brain systems.

Dahl cites important research by Dr. William Greenough, who discovered that rats living in enriched social environments (with little rat playgrounds and play pals) developed heavier, healthier brains than those living in deprived environments. For Greenough’s research, says Dahl, “He had to pick rats in the adolescent period of time, and he had to have other rats there. Otherwise there was no way to get rats to practice new things.”

Research on rats reveals that even adolescent rats prefer to hang with their peers than with older and younger rats. Same with monkeys, Dahl says. And, “Not only are rats directed toward their peers, but they’re [also] much more exploratory, playful, they prefer rough-and-tumble play, and they’re practicing all sorts of social skills.”

Adolescence is evidently a time of important brain development — perhaps not as robust as in early infancy, but unique. And it’s a time of tremendous opportunity for parents to aid their teens’ brain development by providing some freedom to experiment and take some healthy risks, which can be teaching tools, while also setting limits to keep them safe. Don’t let your speed-loving teen start street racing in the family sedan, of course, but do offer to enroll her in snowboarding lessons.

And about that family sedan: “One of the areas where there’s been excellent practical research is in terms of driving,” says Dahl. A teen’s propensity for auto accidents doesn’t appear to be connected to driving skills, because kids with learner permits have lower accident rates than those with newly earned licenses. The key, says Dahl, is having an adult in the car to temper the emotional arousal of being alone in the car — or, worse, being with friends. “The practical side of this is a graded license program,” says Dahl. “First, only drive with an adult, then only [drive] alone with no friends and in daylight. You have to allow kids to gradually develop self-regulatory skills. It’s a balance of giving them some freedom and having them prove that they’re ready to go to the next step. It’s a good set of principles that would apply to other kinds of freedoms.”

Teens will be teens. They have the brains for it. But with some direction and understanding of the changes under way, the emotional passion of adolescence can bring parents as much joy as terror. And, as Bryan Danielsen can attest, eventually your children grow out of it. His son with the passion for piercing? He went on to an honorable four-year career in the Navy, including two stints in Iraq. “Our relationship is better than it’s ever been. We survived the teenage years,” says the senior Danielsen. “I knew it was over for us last October, when he became a father. I have now transferred the parents’ curse that my mother put on me. You know the one — ‘I hope your child acts just like you, son!’ ”