Teenagers are the most accurate representation of adolescence. However, the changes in the brain that lead to the famously bad choices of adolescence do not start at 16 or 17 years old; they begin around the ages 11 or 12 and the beginning of puberty. The dirty little secret of adolescence is that the cloudy judgement and risky behavior may not last a year or two, but rather a decade.
To understand this, taking a look at an experiment may help. At Temple University, psychology professor, Laurence Steinberg, and his team put a group of adolescents into an FMRI machine–a brain scanner–and asked them to play a driving game. Steinberg explained the set-up, explaining that “your perspective if that of a person behind the wheel. And you come to a series of intersections, and the lights turn yellow. And you have to decide whether to put the brakes on or not.
Surprisingly, the adolescents did not blow through the yellow lights. “When adolescents are playing this game by themselves, they don’t take any more chances than adults do when they’re playing it by themselves.” Steinberg explains. This is a big deal because the adolescent brain has a bad reputation for bring consistently impulsive. Steinberg hopes to set the record straight that kids are not hard-wired to always make bad choices.
So then, why do adolescents still make so many bad decisions? To find out, Steinberg added a twist to his experiment. He gave his subjects an adolescent crowd. “This doubles the number of chances that adolescents take,” Steinberg says, “but has no effect on the number of chances adults take.”
In short, an adolescent’s weakness is other adolescents. This is not just referencing peer pressure, but the mere presence of peers makes them less cautious. B.J. Casey, a neuroscientist at Weill Cornell Medical College says that one reason is that “the brain is being marinated in gonadal hormones during adolescence. Another big reason is that the prefrontal cortex is still a work-in-progress and it serves a vital role in our decision-making. The prefrontal cortex “helps to link past experiences to the current situation,” Casey explains, “and, at the same time, consider what the future consequences are of choices and actions that are made.”
The limbic system–the emotional center of the brain that’s always on the lookout for threats and rewards–sends a message to the prefrontal cortex when it spots either because it cannot make sense of these things on its own; it needs the prefrontal cortex. Here’s the problem: for kids in adolescence, the prefrontal cortex is still developing, and it can’t keep up with the limbic system as it goes into reward-seeking super speeds. “It’s as if these emotional regions hijack the prefrontal systems,” Casey says, “and it leads to a choice that they make that’s a bad one. And they even know it’s a bad one.”
This brings us full-circle to Steinberg’s driving experiment. A 12 year-old gets a kind of high simply by being around other adolescents. They’re wired to seek each other out and develop the skills they’ll need to leave their parents, feed and protect themselves and raise children. In the short-term, that means cloudy judgement and risky behavior. Luckily, adolescence is all about the long view.