Brain scans show risk is more fun when friends watch
Published on October 16, 2011 by Nancy Darling, Ph.D.
I love Car Talk, NPR's car centered talk show starring Tom and Ray Maggliozi.
The Car Guys claim that many of the dumbest things ever done are preceded by the immortal words Hey guys! Watch this!
I think they call them “famous last words.”
They must know a lot about teenagers.
Adolescents and Risk
Adolescents are known for taking risks. Although generally healthy, they spend a lot of time in hospitals - mostly because they do dumb things. They crash cars. They drink too much. They skateboard while texting. They have unprotected sex with condoms in their pockets and drink too much with people they barely know.
Contrary to stereotypes about teenagers, though, this is NOT because they don't know better. They do. If anything, adolescents over-estimate the risks of things like drunk driving. They should - adults warn them about risks all the time. And it's not that they think they're invulnerable. Teens don't think they're any more immortal than adults do.
Kids take risks because risky behavior is FUN. It feels good. And, as I said in my last piece, Teens Respond To Pleasure, Not Pain, that's important in understanding adolescent behavior.
The Dual Systems Model of Risk
Recent work by developmental psychologist Laurence Steinberg suggests that adolescents' willingness to take risks is due to the mismatch in the growth rate of three areas of the brain associated with risk taking: the ventral striatum, the orbitofrontal cortex, and the lateral prefrontal cortex.
His work suggests that the timing of growth in this areas puts kids in the position of a car with too much accelerator and not enough brake.
Risk seeking is based on two primary processes: sensation seeking and impulse control. Sensation seeking—taking pleasure in strong positive experiences—is situated in the ventral striatum and the orbitofrontal cortex, both of which process incentives. Impulse control—what keeps us from acting prematurely—is situated in the lateral prefrontal cortex.
The two systems are related, but different. and grow at different rates:
- The incentive processing centers become sensitized right after puberty, making adolescents take much more pleasure out of rewards. This leads them to experience risk as relatively more pleasurable.
- The impulse control centers of the brain develop more slowly over time, and are still developing in early adulthood. This is the part of the brain that keeps you from doing risky things before you think through the consequences.
Because of the difference in the timing of their development, for much of middle adolescence, kids are very sensitive to rewards but have not yet fully developed strong impulse control. Thus Steinberg's analogy of the accelerator without a brake.
Sensitive to Pleasure? Now Bring in Friends
A recent piece by Chein and colleagues, Peers increase adolescent risk taking by enhancing activity in the brain's reward circuitry, provides compelling evidence that when teens are with friends,
- they take more risks
- the areas of their brain associated with incentive processes are activated
Importantly, this does NOT happen in adults as young as their 20's.
In Chein's study, high school students, college students, and young adults come into the lab with friends and play a video game. The goal is simple: and frighteningly similar to real-life.
You're a driver in a hurry. You need to get from Point A to Point B as quickly as possible. There are stop lights. When the light turns yellow, you can hit the brake and wait or you can try your luck. If you're lucky, you get through quickly. If you don't, you crash.
They got great results. When high school students knew friends were watching them, they took significantly more risks than when driving alone. And they also crashed more.
Neither college students nor adults behaved that way. Their behavior was similar in both conditions. In fact, they crashed less when friends were watching (although this difference was non-significant).
The higher crash rates in the peer conditions was NOT because teens were distracted by noisy friends. That's important. Often, we attributed to poor driving performance in cars crowded with teens to the noise and distraction. And that may well be a factor.
But not in this study. Here, drivers were told that friends were watching them. But the friends were in the other room, watching on a monitor. So it couldn't be that the friends were distracting. The participants just knew they were there.
Peeking into Kid's Brains
But why the difference?
Chein and colleagues performed MRI scans of their participants while they were doing the driving task. Again, they had the participants do it alone and then knowing that friends were watching them.
Two things about these findings are interesting and—frankly—scary.
First, high school students, but not college students or young adults, showed activation of the ventral striatum and frontal cortex in the presence of peers. What do these brain areas do? Activation suggests that they are primed to experience and evaluate pleasure (incentive processing). In other words, these findings indicate that in the presence of peers, teens experience things as more pleasurable.
Second, college students and adults show evidence of left lateral pre-frontal cortex activation when doing the task. High school students don't. What does this area of the brain do? Puts on the brakes and controls impulses. In other words, the area of the brain associated with judgment doesn't come on-line during the driving task at all until college. That's scary.
Hey Guy! Watch This!
Alone, high school students, college students, and young adults all perform similarly on this simulated driving task.
But put them with friends, and younger kids take way more risks.
Why? Because it just feels good. Everything is more exciting. The risks are more pleasurable. And the rewards of taking risks are just that much more salient.
Although speculative, you can think about the implications of these findings . . .
- for driving
- for gambling
- for sex
And also for positive outcomes
- for taking a hard class
- for learning something new
- for trying a new job or career
- for studying abroad
Even for watching movies.
One of the strengths and charms of teenagers is that they are ready and willing to try new things.
That's also what puts them at risk.
The better we understand this, the more effectively we can use this knowledge to help teens explore and try new things and stretch themselves. Even change the world.
And the better we can help them protect themselves from these very same impulses when they put themselves in danger.
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