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Adriana Galván: How Does The Teenage Brain Make Decisions?

Mar 5, 2021
Originally published on March 8, 2021 5:24 pm

Part 2 of the TED Radio Hour episode Life Stages Of The Brain

Teenagers often make risky choices that appear absurd in the eyes of their parents. But neuroscientist Adriana Galván says these decisions are critical for adolescent brain development.

About Adriana Galván

Adriana Galván is a Professor of Psychology at the University of California, Los Angeles, where she serves as the Jeffrey Wenzel Term Chair in Behavioral Neuroscience.

Her work focuses on brain development — how cognitive and social behaviors change from childhood to adulthood. Through her research on the teenage brain, she seeks to inform youth-related policies such as juvenile justice.

Galván also serves as Dean of Undergraduate Education at UCLA. She completed her B.A. in Neuroscience and Behavior at Barnard College, Columbia University and her Ph.D. in Neuroscience at Cornell University.

Copyright 2021 NPR. To see more, visit https://www.npr.org.

(SOUNDBITE OF MUSIC)

MANOUSH ZOMORODI, HOST:

On the show today, ideas on healthy brain development at every stage of life, including the next stage - adolescence. I am the parent of two kids who are just on the cusp of being teenagers, and I am slightly terrified. In my mind, I have this constant reel of stereotypes pulled from all the teen movies that I grew up watching.

(SOUNDBITE OF FILM, "THE BREAKFAST CLUB")

JUDD NELSON: (As John Bender) Eat my shorts.

ZOMORODI: I feel almost programmed to think that teens are selfish...

(SOUNDBITE OF FILM, "FREAKY FRIDAY")

LINDSAY LOHAN: (As Anna Coleman) It's about the audition. You're ruining my life.

ZOMORODI: ...Dramatic...

(SOUNDBITE OF TV SHOW, "THE BRADY BUNCH")

EVE PLUMB: (As Jan Brady) Marcia, Marcia, Marcia.

ZOMORODI: ...Hormonal...

(SOUNDBITE OF FILM, "EMPIRE RECORDS")

LIV TYLER: (As Corey Mason) Because it more than love, and it wasn't just some stupid feeling in my...

ZOMORODI: ...Impulsive...

(SOUNDBITE OF FILM, "AMERICAN PIE")

ALYSON HANNIGAN: (As Michelle) And one time at band camp...

ZOMORODI: ...Just kind of dumb.

(SOUNDBITE OF FILM, "EMPIRE RECORDS")

ANTHONY LAPAGLIA: (As Joe Reaves) How old are you?

BRENDAN SEXTON: (As Warren) Old enough to kick your butt through your skull and splatter your brains on the wall.

LAPAGLIA: (As Joe Reaves) Yeah. He's a juvenile.

ZOMORODI: But on the other hand, I know that's not fair.

ADRIANA GALVAN: It's absolutely not fair. I think adolescents get a really bad rap.

ZOMORODI: This is Adriana Galvan.

GALVAN: And I am a professor of psychology at UCLA.

ZOMORODI: Specifically, Adriana studies the science behind the ever-changing adolescent brain.

GALVAN: And adolescents are actually an awesome set of people who are in this wonderful time in life when they are naturally inclined to explore and to try new things and to make new friends. And sometimes maybe it gets them into trouble, but for the most part, most of us get through adolescence relatively unscathed, and we emerge as more confident, self-assured people who are interested in the world.

(SOUNDBITE OF TEDx TALK)

GALVAN: Hi. Thank you. I love your enthusiasm.

ZOMORODI: This is Adriana on the TED stage. She says that normalizing the sometimes seemingly abnormal but actually very normal teenage brain is important, so important that she gave a TED talk about it to teenagers.

(SOUNDBITE OF TEDx TALK)

GALVAN: How does the teenage brain make decisions? One of the first discoveries relevant to this topic was made when we discovered that the part of your brain in the very front - called the prefrontal cortex, which is the last brain region to develop because your brain develops from the back to the front - continues to change up until the mid-20s. And the reason this is relevant is because the prefrontal cortex is a part of your brain that helps you think about the consequences or potential consequences of your actions before you do them. It helps you regulate your behavior and your emotions. And so it makes sense that if this part of the brain isn't fully available until well past adolescence, then teenagers may make more impulsive decisions with less regard for the potential future consequences.

But we now know that the story is far more interesting and complicated than that. And, in fact, what we really need to do is think about how brain regions that are not at the surface of your brain, but in the deeper layers - how they change. And one region we focus on is called the striatum. And the striatum is the key component of the reward system. So when you receive something that you find rewarding, your striatum is very responsive, and it releases something called dopamine. So in my lab, we study this reward system.

ZOMORODI: In her lab, Adriana does all kinds of research to understand this reward system, like using fMRI machines to study the brains of kids, adults and teens, specifically looking at the striatum to see what they find rewarding.

(SOUNDBITE OF TEDx TALK)

GALVAN: And what's something that people find rewarding? Sugar. We hooked them up to a straw, and we fed them squirts of sugar water every so often. And you can see that everybody liked it.

ZOMORODI: Kids liked it. Adults liked it. But teens really liked it.

(SOUNDBITE OF TEDx TALK)

GALVAN: It's the teenage brain that was going crazy. It was really excited to get it.

ZOMORODI: It's not just that they liked it more. They craved it more.

(SOUNDBITE OF TEDx TALK)

GALVAN: So this is telling us that there's something really special about the teenage brain. There's a sharp increase in sensitivity to rewards and novel information from childhood to adolescence. But then there's a sharp decrease from adolescence to adulthood. And that probably has something to do with the fact that the prefrontal cortex is starting to come online as people transition into adulthood and regulating the emotional response to rewarding information.

ZOMORODI: So Adriana understood that teenagers' brains respond more to rewards. But how does that affect their decision-making?

GALVAN: For example, if we want to test how the adolescent brain responds when they are taking a risk, we try to mimic and present them with a virtual environment where they're asked to take risks. Adolescents are on a racetrack - simulated, of course - and they're told that they have to get to the end as quickly as possible to earn some extra money. And they'll come to a stoplight.

ZOMORODI: Oh, no.

GALVAN: Well, what we find is that adolescents compared to adults are more likely to run the yellow light.

ZOMORODI: (Laughter).

GALVAN: So that's our measure of risk. They're simply more active in their reward system. And that tells us that, given the very same exact conditions, the adolescent brain is perceiving that risk differently. And not only is the brain perceiving it differently, but it actually leads to a difference in their behavior that we can observe, that we can measure.

ZOMORODI: OK, so adolescents were willing to take bigger risks to get the reward. But how do consequences fit into all of this then?

GALVAN: Well, it's not that they don't understand that they could get in trouble for sneaking out at night or that they could get in trouble for running the light, but that the rewards of that are much more powerful. And if we think about how those rewards happen or the context in which those rewards or risks occur, it's typically when they're hanging out with their friends. Very few teenagers take risks alone and - because there's a thrill to being with your friends, making your friends laugh, for being the hero, for kind of being defiant or doing something that adults don't want you to do.

And that, too, is a part of establishing independence. It's kind of saying to adults, yeah, I know it's wrong, but you know what? I want to do it anyway. And for adults, we say, well, that's such a stupid decision. That's a risk that could have killed someone. You could have really gotten in trouble. You could jeopardize your standing in school or something like that.

But for adolescents, the real risk is not fitting in. The real risk is not getting that social capital. And so maybe it's actually a very rational decision to sneak out of the house if that's what's going to get you some bonding experience. I'm not suggesting teenagers should do it, but I'm just saying that the calculation is different for adolescents than for adults.

ZOMORODI: So what you ultimately are arguing in your talk is that while risky behavior can be dangerous, it's actually really necessary for teens to learn and to grow.

GALVAN: Yeah. This same - this reward system that I'm talking about is also what responds to novelty. And that's what - adolescence is all about novelty, right? Because you've already gotten the basics down. You know how to walk. You know how to talk. You know how to bond to your caregivers.

But what's new is that you're learning new things in school. You're being exposed to poets. You are learning calculus. You are also learning about love. You're having your first crush. You're starting to think about college and your life and your identity separate from your caregivers. And all of that is super exciting. And it's no coincidence that our brains have evolved in a way to have this period in life when novelty is super exciting.

ZOMORODI: Yeah, I guess there's now an opportunity for this kind of pure passion to be expressed. I mean, thanks to the world we live in now with social media - like, just thinking over the past few years, young people have become so influential, like Malala Yousafzai and Greta Thunberg and more recently, the poet Amanda Gorman.

GALVAN: Yeah.

ZOMORODI: And I wonder, like, do you feel kind of triumphant that now teens can truly be fearless publicly and express themselves in new ways?

GALVAN: Absolutely. I'm so excited that you said that because so many wonderful things about adolescents - that they mobilize, that they're energetic, that they're really passionate about causes they believe in, but they're able to influence other people to think pro socially about how they can make the world a better place. And because they don't have the experience or the cynicism that maybe sets in as we get older, they are fearless.

And that's part of what makes adolescents, adolescents - that they're fearless, passionate and want to influence other people. They want to connect with other people on things they care about. And social media has given them that opportunity to do so.

ZOMORODI: That's Adriana Galvan. She's a neuroscience professor and dean of undergraduate education at UCLA. You can see her full talk at ted.npr.org. Transcript provided by NPR, Copyright NPR.