DAVID GREENE, HOST:
The teenaged brain always gets a bad rap. It's often described in terms of its weaknesses, especially a tendency to engage in impulsive. But as NPR's Jon Hamilton reports, new research shows that teenaged brains have considerable strength as well.
JON HAMILTON, BYLINE: About a decade ago, scientists began publishing studies of the adolescent brain that led to a pretty negative stereotype.
BJ CASEY: The adolescent is described as someone who's impulsive, and who makes poor choices and is a risk taker.
HAMILTON: That's BJ Casey, a brain scientist at Weill Cornell Medical College in New York. Casey says she's actually responsible for some of the studies suggesting that the teenage brain is like a speeding car with no steering wheel and no brake. But on this day, she's taking part in a session at the Society for Neuroscience meeting in New Orleans to help set the record straight.
CASEY: Teenagers are quite capable of waiting, as opposed to reacting impulsively, and this really flies in the face of some of my previous research.
GREENE: Casey says a new study from her lab makes this point in a powerful way. Interestingly, much of the work was done by a graduate student named Theresa Teslovich, who was an adolescent herself not so very long ago.
HAMILTON: Casey says the study involved the brain's reward system, which produces pleasurable feelings in response to things including alcohol, sex, and thrill-seeking activities like skydiving. Casey says previous research has shown that, compared with adult brains, adolescent brains have a much greater sensitivity to rewards.
CASEY: Such a sensitivity that you're seduced to do things you know you shouldn't do in the heat of the moment.
HAMILTON: But Casey and Teslovich wanted to know whether that sensitivity to reward could also encourage good decisions. So they studied the brains of teenagers and adults playing a video game. Participants earned points for correctly deciding which way clouds of dots were moving on a screen.
Casey says when a lot of points were at stake, the reward system in adolescents, but not adults, became much more active. But she says despite all the activity in the reward system, adolescents actually waited longer than adults before making a decision.
CASEY: So what the adolescents appear to be doing in this case, as opposed to acting impulsively and being pulled by that reward, they're making sure and letting enough evidence accumulate, so that they get it right.
HAMILTON: Casey says this suggests parents might want to consider rewarding good decisions by teens rather than punishing bad ones.
Another study presented at the neuroscience meeting also found that teenage brains can make good decisions, though teens arrive at them in a different way.
A UCLA team reported that teens use more areas of the brain than adults do when assessing the same risk.
Jay Giedd of the National Institute of Mental Health says this sort of research is leading brain scientists to a more nuanced view of adolescence.
JAY GIEDD: It is a time of vulnerability. But it's also a time of enormous opportunity.
HAMILTON: Giedd and other scientists say it's now clear just how quickly the brain is changing during the teen years, and how flexible it is.
GIEDD: The teen brain isn't broken and it's not a defective adult brain. It's been exquisitely forged by evolution to be different than children and different than adults. But these differences have served our species very well.
HAMILTON: By helping each generation of adolescents adapt to a world that may be very different from the one their parents grew up in.
Jon Hamilton, NPR News.
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