They say you never escape high school. And for better or worse, science is lending some credibility to that old saw. Thanks to sophisticated imaging technology and a raft of longitudinal studies, we’re learning that the teen years are a period of crucial brain development subject to a host of environmental and genetic factors.
This emerging research sheds light not only on why teenagers act they way they do, but how the experiences of adolescence—from rejection to binge drinking—can affect who we become as adults, how we handle stress, and the way we bond with others.
One of the most important discoveries in this area of study, says Dr. Frances Jensen, a neuroscientist at Harvard, is that our brains are not finished maturing by adolescence, as was previously thought. Adolescent brains “are only about 80 percent of the way to maturity,” she said at the annual meeting of the Society for Neuroscience in November. It takes until the mid-20s, and possibly later, for a brain to become fully developed.
An excess of gray matter (the stuff that does the processing) at the beginning of adolescence makes us particularly brilliant at learning—the reason we’re so good at picking up new languages starting in early childhood—but also particularly sensitive to the influences of our environment, both emotional and physical. Our brains’ processing centers haven’t been fully linked yet, particularly the parts responsible for helping to check our impulses and considering the long-term repercussions of our actions. “It’s like a brain that’s all revved up not knowing where it needs to go,” says Jensen.
It’s partially because of this developmental timeline that a teen can be so quick to conjure a stinging remark, or a biting insult, and so uninhibited in firing it off at the nearest unfortunate target—a former friend, perhaps, or a bewildered parent. The impulse to hurl an insult is there, just as it may be for an adult in a stressful situation, but the brain regions that an adult might rely on to stop himself from saying something cruel just haven’t caught up.
Or consider risky sexual behavior. Recent studies suggest that the teen brain is particularly sensitive to activities—like sex—that trigger a response in the neurotransmitter dopamine, the same chemical often associated with both addiction and healthier behaviors having to do with motivation and reward.
Full story: The kids can’t help it