1:00pm

Tue September 20, 2011
NPR Story

Understanding The Mysterious Teenage Brain

Originally published on Wed May 23, 2012 11:23 am

It's a question that has plagued parents for generations: Why do teenagers act the way they do? Why the angst, anger and unnecessary risks? Many scientists say a growing body of research may provide some answers.

After his son was pulled over for driving 113 mph, science writer David Dobbs set out to understand what researchers know about the teenage brain. The resulting story, "Beautiful Brains," is the cover story in the October 2011 issue of National Geographic magazine.

Dobbs and brain researchers BJ Casey and Dr. Jay Giedd share their findings on what science can tell us about the teenage brain.


Interview Highlights

On why teens need to push limits

Dobbs: "The hardest thing we ever do is leave home. It's hard emotionally. It's extremely hard intellectually and logistically. It's a real challenge. So the disincentives to do it are very strong. And as both B.J. and Jay pointed out to me at different times, if you look at the things that characterize adolescence in almost all cultures — risk, novelty-seeking and the affiliation of peers — that's the perfect menu to actually motivate you if you are 14 or 15 or 16 or 18 years old to get out and explore the world, even though it's hard to do and the risk is tremendous. You have to have taste for risk at that time of your life."

On how teens measure risk differently from adults

Dobbs: "Researchers have actually found that they don't think they're invincible. They know they can die. And they also don't underestimate risk. What they do is they overestimate risk less than adults do. If you screen them for if they understand risk, they understand [it] actually better than adults do. They just don't exaggerate the risk as much.

"And the big difference, there are rewards in some situations — like driving fast down the highway with your friends — that they care more about than adults will, which is why it's not that they don't understand the risk. It's the balance changes. They see more benefit in certain things."

On why teens shouldn't see the research as license to run wild

Casey: "I think it's very important that you acknowledge accountability, because we don't want teenagers to think that they're just free to be risk-takers and that there is no other way. This is a time when they need to explore, but they also need to recognize the limits within society of what they can and they cannot do. That's part of transitioning from dependence on parents to independence and being a pro-social adult."

On how moms and dads can use these developments to parent better

Giedd: "Our brains are better at learning by example and by modeling. And so as a parent, we're often much more effective in just little things, how we treat our spouse, how we treat strangers, how we deal with the stresses and time management of our day-to-day life. So it's not always, sort of, sitting down and having these big talks. It's the little things every day that you're modeling. And I think it's good for us parents ... to realize ... we're always on. And whenever we're with them, that's how their brain is learning how to be an adult, how to take the next step."

Copyright 2012 National Public Radio. To see more, visit http://www.npr.org/.

Transcript

NEAL CONAN, host: This is TALK OF THE NATION. I'm Neal Conan broadcasting today from the National Geographic headquarters in Washington, D.C. A few months ago, David Dobbs got a phone call from his teenage son, who'd just spent a few hours in the custody of the state police. His son told him he'd been driving a little fast. That turned out to be 113 miles an hour.

Dobbs stifled the impulse to yell after his son calmly accepted the consequences, said he would pay all the legal fees, but there was a curious caveat: He was not willing to accept the characterization of his infraction as reckless driving. He knew exactly what he was doing, he said.

He chose a long, empty, dry stretch of highway on a bright, sunny day. Which traces the age-old question: Why do teenagers do these crazy things? In a moment, we'll hear answers that science has come up with. We'd also like to hear from the current and former teens in our audience. Why?

Our phone number is 800-989-8255, email talk@npr.org. You can also join the conversation on our website. That's at npr.org. Click on TALK OF THE NATION. We're going to take questions from members of the audience here in the Grosvenor Auditorium, as well, and welcome to all of you.

(SOUNDBITE OF APPLAUSE)

CONAN: And let's begin with David Dobbs. His article "Beautiful Brains" is this month's cover story in National Geographic. Nice to have you with us today.

DAVID DOBBS: Thanks for having me.

CONAN: And temporary insanity was not the explanation?

DOBBS: For my son's high-speed adventure?

CONAN: Yeah.

DOBBS: No, the explanation is hard to come by. I mean, I never actually asked him why did you do this. I think I knew why he did it: because it would be fun. It would be a new adventure. I wasn't surprised later, as I started to look into the science of the teen brain that it expressed several things typical of teens and that are more typical - that we all have when we're teens. And it's never more so than then.

And one is an either tolerance or actual taste for risk; a real drive to be with their peers, meaning he had friends in the car; and a taste for novelty, he hadn't driven 113 before, so I guess he decided he would do it that day. And - but as he wanted to stress when I talked to him, it wasn't reckless in every sense of the world, although in several senses of the word it was.

There was some deliberation to it. I don't think it forgives it, but it alerts you to the fact that there's - it's not as simple as he's being an idiot. He's in pursuit of another positive agenda in the sense of actually going after something, not just lacking something.

CONAN: In your article, you find that there were essentially two different explanations, one of them prompted by advances in technology, the brain imaging that we've been able to use, what, these past 20 years or so.

DOBBS: Yes, the science of the teen brain has really gotten a huge surge in the last 20 years or so. And as I describe in the article, a lot of it's because of a series of brain scans that were done on lots of teenage - well, kids starting early in life and tracking them through, up into their 20s, done by Jay Giedd, who's next to me at the table, and some other researchers, that discovered something unsuspected, which is that it takes until we're about 25 before our brain is almost completely developed. This is an arc that previously thought ended maybe around age 10.

CONAN: Well, let's ask Dr. Jay Giedd, chief of the unit on brain imaging in the child psychiatry branch at the National Institute of Mental Health, who's also with us on the stage, as mentioned. Nice to have you with us today.

JAY GIEDD: Thank you very much.

CONAN: And not merely developments in the brain that don't end until 25, but they seem to progress in a certain direction.

GIEDD: Actually, even though B.J. is younger than me, she was my first mentor, and we started this together in 1991.

CONAN: Dr. B.J. Casey is also with us. We'll get to her in just a minute.

GIEDD: And so we've been along for these advances, and the technologies had allowed us for the first time to look inside a living, growing human brain. And the most fundamental thing that we found is that despite the anecdotes we've just heard and the frustrations of parents at times, the most fundamental thing I can say is that the teen brain is not a broken or defective adult brain.

It's been exquisitely forged by the forces of our evolutionary history to be a very good teen brain. It's different than children, it's different than adult, but it's not broken.

CONAN: Well, we keep hearing that adolescence is sort of a creation of our culture, that really the teenage years didn't exist. Kids went to work when they were 12 or 13 years old.

GIEDD: I'm just returning from an international conference in Berlin, where adolescence from around the world was discussed. And in Western cultures, Jeffrey Arnett at Massachusetts has explored this notion of emerging adulthood, that the time that we become independent and self-sufficient has now become late 20s instead of late teens.

And so we're very late to get married, to have our final job, to have the house that we're going to live in for a long time, to raise a family. All of these ages have gone up and up since the 1970s.

CONAN: Yeah, before that, it's the basement we live in alone.

GIEDD: Yeah, yeah, but the following speaker was a Professor Omagulabab(ph), who was from Nigeria and noted that there many of the girls are committed to marriage at age nine, that it's considered shameful if they have their second menstrual period while still living at home, genital mutilation, many of them die during childbirth because they're not allowed into the hospital without being accompanied by their husbands.

And so it struck me that we, B.J. and I, we study these biological tendencies, but they are just that, tendencies, that these social forces can completely overwhelm the biology tendencies and that almost everything we'll talk about today is a very intricate relationship between the biology and the environment. And so it is very much culturally rooted.

CONAN: And let me now introduce Dr. B.J. Casey, director of the Sackler Institute for Developmental Psychobiology and a professor of developmental psychobiology of Weill Cornell Medical College. And nice to have you with us, as well.

B.J. CASEY: Thank you.

CONAN: And this combination of the biology, as our brains continue to develop and form in some interesting ways, I mean for example the discovery that the frontal lobe, the executive center of our logic and our - it doesn't function the same way in adolescents as it does in adults.

CASEY: Right, in fact Trekkie fans might refer to their prefrontal cortex more as the Vulcanized part of the brain.

CONAN: The Spock brain.

CASEY: Exactly, the Spock brain, whereas deep structures in the brain that are involved in desire and our emotions, those systems seem to be really pulling and maturing at a time in adolescence that really allow the individual to leave the home.

If our children weren't experimenting, if they weren't telling us about their bad behavior and the sort, we may be more inclined to want to keep them in the home. So there's this tension between these systems...

(SOUNDBITE OF LAUGHTER)

CASEY: I mean, we do want to keep them around. I just - but at the same time, so I mean, so the question we all asked ourselves is: Why would the brain be tuned this way, to kind of want to pull you out and sort of get you in harm's way?

CONAN: And David Dobbs, you came to the conclusion in the piece that in fact what you wrote is that leaving home is the most difficult thing we do and that in fact it is the characteristic of human beings not merely to leave home but say I wonder what's on the other side of that hill or that lake or that ocean.

DOBBS: It's exactly so. It is the hardest thing we ever do is leave home. It's hard emotionally. It's extremely hard intellectually and logistically. It's a real challenge. So the disincentives to do it are very strong. And as both B.J. and Jay pointed out to me at different times, if you look at the things that characterize adolescence in almost all cultures - risk, novelty-seeking and the affiliation of peers - that's the perfect menu to actually motivate you if you are 14 or 15 or 16 or 18 years old to get out and explore the world, even though it's hard to do, and the risk is tremendous. You have to have taste for risk at that time of your life.

CONAN: We want to get some callers involved in the conversation. We want to hear from those of you here in the audience at the Grosvenor Auditorium, as well. 800-989-8255. Email us, talk@npr.org. You can also, those of you here in the audience, turn in your cards. Don't forget to put your names on them. We're going to start, though, on the phones, and we'll go with Stu(ph) and Stu is with us from Vermillion in South Dakota.

STU: Hi, how are you today?

CONAN: Very well, thanks.

STU: I'm 27, and I have three children and a steady job, working on my physics degree. But three years ago, you probably wouldn't have recognized me because - you probably wouldn't even have seen me because I would have driven by you so fast.

(SOUNDBITE OF LAUGHTER)

STU: And I think that it was just something that had to get out of my system. I got in some trouble here and there, but in the end, it was just was I ready to slow down and stop being a teenager and, you know, taking risks and doing that sort of behavior. You know, it was just inexplicable.

But of course, the responsibilities of adulthood do catch up, and at some point you're ready. And I guess my question to the guests today on the show would be, you know, the ready availability of computerized records for potential employers or schools or even, you know, in-laws, that sort of thing...

(SOUNDBITE OF LAUGHTER)

STU: How is that changing as an overall trend? I mean, I found it real hard to come back from some mistakes, even though, you know, a more dependable person always comes out after time, as a person matures. That's sort of an open-ended thing, but if anybody could comment on that.

CONAN: It's a good question, and we're going to keep you on the line so the state police can trace your location.

(SOUNDBITE OF LAUGHTER)

STU: I don't have my motorcycle today, don't worry about it.

(SOUNDBITE OF LAUGHTER)

CONAN: Anybody have an answer?

GIEDD: Yes, I can - it raises two points for me. One is the goals as a parent or as a society for the adolescent years. I see them largely to prevent irreversible mistakes in terms of motor vehicle accidents, incarcerations, suicide, homicide, sexually transmitted diseases, unwanted pregnancies.

And the technologies of the day do make it sort of harder to abandon our past in terms of - at the NIH and other places, we often will Google the applicants and see their Facebook sites and their other activities. And in some ways, the Internet is forever in terms of that's changed.

But it's also changed even more fundamentally in that the way get information, the way that we entertain ourselves, the way that we interact with each other has changed more in the last 10 years than it has in the previous 570 since Gutenberg's introduction of the printing press.

And there's just a gusher of information coming in from the Internet, from iPod, from cell phones, from Twitter, from Facebook, that this explosion of input has really changed the teen's life and existence. And so we're trying to explore what are the good and bad effects of this change.

CONAN: Stu, thanks very much for the call.

STU: Thank you.

CONAN: We're going to have more with David Dobbs, Dr. B.J. Casey and Dr. Jay Giedd, who you just heard, what we know now about the teenage brain and why teens take the risks they do. Stay with us. I'm Neal Conan. It's the TALK OF THE NATION from NPR News.

(SOUNDBITE OF LAUGHTER)

CONAN: This is TALK OF THE NATION, from NPR News. I'm Neal Conan. Adults often think of teenagers as impulsive, even reckless at times. Moody might also sound familiar to some parents. As David Dobbs writes in this month's National Geographic, these are natural signs of an organism learning how to negotiate its surroundings.

As it turns out, many of the things that drive mom and dad crazy may prove key to their offspring's success. Today, we're trying to answer the age-old question: Why do teenagers do these crazy things? We want to hear from current and former teens in the audience. Why? 800-989-8255. Email: talk@npr.org. You can also join the conversation at our website. That's at npr.org. Click on TALK OF THE NATION.

And we're going to be taking questions from the audience here in the Grosvenor Auditorium. Our guests again, David Dobbs, who wrote the cover story in this month's National Geographic titled "Beautiful Brains," also Dr. B.J. Casey, director of the Sackler Institute for Developmental Psychobiology at the Weill Cornell Medical College, and Dr. Jay Giedd, who serves as chief of the unit on brain imaging in the child psychiatry branch at the National Institute of Mental Health.

And here's an email from Jeff: What causes teenagers and early, mid, late-20s to feel invincible? I know that I did. And David Dobbs, there was an interesting answer to that in your article.

DOBBS: Yes. There's been a bunch of studies done exactly of that: Do teenagers think they're invincible, and do they think they're immune to risk? Or do they underestimate risk? And with a bunch of different methods and tests, they actually found - researchers have actually found that they don't think they're invincible.

They know they can die. And they also don't underestimate risk. What they do is they overestimate risk less than adults do. If you screen them for if they understand risk, they understand them actually better than adults do. They just don't exaggerate the risk as much.

And the big difference, there are rewards in some situations - like driving fast down the highway with your friends - that they care more about than adults will, which is why - it's not that they don't understand the risk. It's the balance changes. They see more benefit in certain things.

CONAN: And B.J. Casey, being with their friends, that's an important part of it.

CASEY: So it's very important, but one more sort of aspect of adolescent development is their ability to think in terms of the future consequences of their behavior. And so we know that this is changing as they're maturing, as well, and with their experiences.

CONAN: Let's get a question from here in the audience.

UNIDENTIFIED WOMAN: Yes. I have a 13-year-old son and a big, beat-up station wagon. But the idea of handing him the keys to that car in three years is just already keeping me awake night. My question is really about whether or not we know things now that would cause us to rethink some of our existing laws: driving age, drinking age, the age that we allow kids to go into the service. Are there discussions like that happening now based on recent science?

CONAN: B.J. Casey?

CASEY: So we were just having a discussion before this about how in states or locations where the driving age is older, you have less accidents. And, in fact, the brain science - particularly behavioral sciences, too, there has been work by Larry Steinberg has really helped start to drive policies in terms of driving.

But I guess what we were sort of laughing about is rental agencies and insurance companies have known this for a long time, based on the statistics.

CONAN: Yeah, they don't rent to anybody under 25. Yeah. And it's interesting, as you look at this, for example, a learner's permit, I know in Maryland, where my children grew up, if you're learning to drive as a teenager, you're not allowed to have other kids of your age in the car.

DOBBS: It's that way in a lot of states. I would also note - I mean, it's - I think it was B.J. - no, Jay was saying earlier, this is very much a matter of traits meeting certain environments. And we tend to focus on behaviors instead of traits and mistake behaviors for traits. Driving fast on the highway is not a trait. It's a behavior, which is one expression of several traits.

But in different environments, these things can be more dangerous than others, and just as in states where the driving age is higher, in cultures where driving is not as essential, they are not - the death rate among teens is lower because they're not - they don't have this toxic mix of being 16, maybe drinking and driving. So there's always this interplay, and you can hopefully adjust the environment to keep them safer.

CONAN: Dr. Giedd?

GIEDD: Yeah, we've been exploring this notion of age of consent recently, and it's almost bafflingly inconsistent. So you would think that there would be some age that the brain would be mature, that it's able to make decisions on its own behalf. But the ages of consent for choosing whether or not to have sex is 12 or 13, depending on the state. To get married is a bit older, at 14, to drink, 16, to vote, 18, down from 21 from 1972, to be mayor, 16, governor, 18, 25 for Senate, 35, president.

There's no consistency across cultures and millennia in terms of what is the age at which we're - you know, our brains are mature enough. And the neuroscience really hasn't been part of these discussions, but I think what's most striking to me is that it goes from ages five, when you can commit religiously to, you know, 35, there's no sort of common clue about when we as a species consider our brains ready to make decisions on our own behalf.

CONAN: Let's see if we can get another caller in. Let's go to Diane, Diane with us from Traverse City in Michigan.

DIANE: Hi. I'm on my cell phone, so I hope you can hear me. But I'm not driving.

(SOUNDBITE OF LAUGHTER)

DIANE: I was 18 and my sister was 16 when I graduated from high school. And we decided to go on an adventure, and we packed my old Ford with two pillows, two blankets, a jar of peanut butter and a loaf of bread and drove up to the Upper Peninsula of Michigan because we'd never been further than 100 miles from Detroit.

On the trip, we traveled through Tahquamenon Falls and decided it was a really good idea to try and get as close to the falls as possible. We ended up climbing over the rocks, going under, behind the falls, me with my super-8 camera going the whole time.

And I think back now of how we could have been smashed to pieces under the power of all that water, because it's, I think, the second largest falls next to Niagara this side of the Mississippi.

CONAN: You're an idiot.

(SOUNDBITE OF LAUGHTER)

DIANE: I was then. I wouldn't do it now.

CONAN: And just to do it.

(SOUNDBITE OF LAUGHTER)

DIANE: Just to do it, because it was something totally different from our experience of growing up in the Detroit area.

CONAN: This, I think, falls under the - well, it is looking for novelty, and it is looking for that sense of adventure that is - turns out to be critical to our species even when they do survive. B.J. Casey?

DIANE: Yes, and my sister has managed to procreate, and her son is now an Outward Bound guide in Minnesota. So, apparently, it's genetic.

CONAN: Yes, lasting effects. B.J. Casey?

CASEY: I was just going to suggest the website has this wonderful risk-taking survey, and it's interesting to complete that when you were adolescent, thinking back to what you did and completing that now as an adult.

DIANE: Oh, yes.

(SOUNDBITE OF LAUGHTER)

CONAN: Thanks very much for the call, Diane. We're glad you made it.

DIANE: Thank you, bye.

CONAN: We have a teenager here at the microphone at the Grosvenor Auditorium.

UNIDENTIFIED WOMAN: Yes, I wanted to ask: Why do we have such a need to have relationships at this age if we know now that we marry at a later age?

CONAN: Well, David Dobbs, there was some fascinating information about this as to explaining why the 13-year-old cries her heart out when she's not invited to the party.

DOBBS: Right. I mean, this is an area where what we know is that we have - we're never more desirous of our same-age peers, of their company than we are when we're teenagers. We can only kind of mostly speculate as to why. But one explanation that makes sense is that this is the cohort that you will live with when you are an adult.

And if you think like an investor, it makes more sense to invest your time and build your social capital among them than it does to continue to do so with your family. Plus, you can be pretty rude to your family, and they'll - they usually won't get rid of you, right. So you can spend...

CONAN: Maybe the Corleones, but...

DOBBS: It depends on the family, right. So there's a sense of investing with the peer group that will be your adult world.

CONAN: B.J., you were...

CASEY: I just wanted to add - so in the brain-imaging studies, a recent one by Larry Steinberg, what he was able to show is in the very same regions that are activated with monetary reward are when you're just about to engage in a risky decision. These same areas are activating when you have a peer next to you or interacting with you when you're in a scanner, and they're watching your performance.

So I think it's very important for us to think about really trying to understand more how peers are really influencing the brain in that way.

DOBBS: It kind of comes down to the absolute importance of social connections. In general, we are extremely social people. And as I put it in the story, you know, sometimes teenagers, you get the sense that their fates depend on whether they are accepted by their peers. In a very real sense, their fates will be decided by how well they are accepted by peers, because how well you do in a social world has everything to do with every other kind of success that you need to live well.

CONAN: Here's an email question from Gina: How would you tackle my 18-year-old son wanting a tattoo? Probably around the waist and then hang on for dear life.

(SOUNDBITE OF LAUGHTER)

CONAN: B.J.?

CASEY: So when my son, actually at an earlier age wanted to have a tattoo, I said great. I'll go with you, and we'll get the same one.

(SOUNDBITE OF LAUGHTER, APPLAUSE AND CHEERING)

DOBBS: So what did you get?

CASEY: He didn't want it.

(SOUNDBITE OF LAUGHTER)

DOBBS: OK.

CONAN: I was going to ask if that prompt...

CASEY: No.

(SOUNDBITE OF LAUGHTER)

CONAN: ...if that prompted the eww. It's a - another question from here in the audience at the Grosvenor Auditorium. Oh, we're not ready for that quite yet. We'll be back to you in just a minute. We're quietly and until I open my big mouth successfully replacing a cable, so we're going to take another caller on the phone. Let's go to Ruby. Ruby with us from Sebastopol in California.

RUBY: Hi. I'm calling just because I think it's fascinating hearing how people respond to stories of our youth and that question of whether or not it's responsible. When I was 16, I lived in a small town. I thought of myself as a pretty good kid, drank way too much, got in the car with a couple of my girlfriends and robbed a local store. Just flowers for Mother's Day.

(SOUNDBITE OF LAUGHTER)

CONAN: What's the statute of limitations there in California?

RUBY: Well, I - in reflecting on it, the funny thing was is that the next day, the chief of police - we live in a small town - came to our house. We talked to them, you know, really reflected on why we did what we did, made sure we never did it again. And it was only through testing the bounds of my invincibility and kind of easing the shame of what I actually did that taught me not only is it not safe to do what I did - 'cause drinking and driving - is dangerous, but there are social implications and long-lasting consequences for those kinds of actions. And I don't think I would have learned that lesson quite the way I did unless I had done something that extreme in my small community. Does that make sense?

CONAN: Everybody is nodding their head. I'm going to ask Dr. Giedd to expound.

GIEDD: I think finding the limits is part of the risk-taking and sensation-seeking phenomenon. It's a better outcome for you than it might have been in terms of the experimentations involving (unintelligible) cars and powerful substances of abuse. These Stone Age tendencies are now interacting with modern marvels that can sometimes not just be amusing anecdotes but can really lead to more lasting effects. So I think it's nice that we have outlets or ways in which we can explore these boundaries that don't lead to irreversible damage.

CASEY: And that also...

CONAN: B.J. Casey.

(SOUNDBITE OF LAUGHTER)

CASEY: Sorry. And also I think it's very important that you acknowledge accountability because we don't want teenagers to think that they're just free to be risk takers, and that there is no other way. This is a time when they need to explore, but they also need to recognize the limits within society of what they can and they cannot do. That's part of transitioning from dependence on parents to independence and being a pro-social adult.

CONAN: Thanks, Ruby, for the call.

RUBY: Can I ask a question if possible?

CONAN: If you make it quick.

(SOUNDBITE OF LAUGHTER)

RUBY: Yeah. It's quick. That - there - I'm curious about the balance between that feeling of exploration and whatever it is that you say the executive frontal lobe of the brain develops as you grow up. Is there something that we lose as we transition to adulthood, that freedom of thought or whatever it is that leaves you more - less inhibited? What is it that we lose as we grow into adults? That's my question. And I'll take the answer off the air. Thank you.

CONAN: OK. Ruby, thank you.

DOBBS: Well, I know...

CONAN: Dave Dobbs, you wrote about this.

DOBBS: Yeah.

(SOUNDBITE OF LAUGHTER)

DOBBS: Everyone is looking at each other up here.

CONAN: Yeah.

DOBBS: What do you lose? Well, you lose some - and some - one thing you lose is some of - all these things we've been talking about, these traits that are characteristic, the risk taking, the novelty seeking and the affiliation of peers, they peak during their mid-teens and fall off. So that's one arc that is falling that would make you less, you know, reckless, adventurous. Meanwhile, what you're getting better at is balancing all the different competing agendas in your head, which - we always have many competing.

And as your brain gets faster and the network in your brain gets richer, it's better able to coordinate all these agendas. You also have a bigger evidence-base, firsthand experience to draw on and make decisions which is why our caller decided not to, you know, steal stuff anymore or drink and drive.

CONAN: Move into the business of...

DOBBS: Oh, yeah, go into it...

CONAN: ...flower stores, yeah. We're talking about the adolescent brain. You're listening to TALK OF THE NATION from NPR News. And, Jay Giedd?

GIEDD: One of the many things that the frontal lobe does is time travel. It allows us to tap into our past, everything happening in the moment, our hopes and dreams of the future. And as our frontal lobe matures from teens to young adulthood, we can play off to these scenarios more in our mind, instead of the physical world where they're in harm's way. And so as we become older, we can still have these urges perhaps to get flowers for mom for Mother's Day or these other sorts of things. But we don't do it because we run through the scenarios of the consequences and what might happen.

CONAN: But at least according to the article, among the things we lose is plasticity, B.J. Casey?

CASEY: Oh, well, we do have less plasticity in terms of being able to learn as quickly and efficiently during development. But I was also just to get back from the question in terms of this risk taking. One of the conversations that I have with my particularly male colleagues who are still risk takers is the minute that they saw this sort of inflexion during adolescence and risk taking, they were like, you see, I'll never get back there. That these are individuals, though, that have learned how to use that sensation seeking in controlled situations like rock climbing or the sort, still dangerous but still relatively controlled and recognizing the safety in them.

CONAN: And quickly, Jay Giedd.

GIEDD: I just - that the word plasticity triggers a thought just because it's so central to the work that B.J. and I do. The - nearby here at the National - History of - Museum of Natural History, the Hall of Human Origins has a wonderful exhibit in which they demonstrate that the size of a human brain increased because of change in climate. And I say change, not harshness. Before seeing this, I would have thought that as times got tough, as food got scarce, as conditions got worse, our brains got bigger and bigger. But that's not quite right. It was the change in being able to adapt that's needed to survive.

CONAN: More on the adolescent brain in just a moment. This is TALK OF THE NATION from NPR News.

Today, we're talking about research into the teenaged brain, mood swings, impulsiveness, the risks. Scientists now think all of that gives us an evolutionary advantage. Our guests are David Dobbs, who wrote the story "Beautiful Brains" in the October issue of National Geographic. You can see some of the photos that accompany his story, including some of the risky behaviors we've talked about. That's in a slideshow at our website, npr.org. You can just click on TALK OF THE NATION.

Also with us is Dr. B.J. Casey, director of the Sackler Institute for Developmental Psychobiology at the Weill Cornell Medical College, and Dr. Jay Giedd, chief of the unit on brain imaging in the child psychiatry branch at the National Institute of Mental Health. And let's get a question from the audience here in the Grosvenor Auditorium.

UNIDENTIFIED MAN: Thank you. Last week, I attended a talk at the National Institutes of Health by Barry Schwartz, who was talking about wisdom. And his point was that wisdom comes from experience, and our resistance to making mistakes and our insistence on making rules prevents people from getting experience and from actually developing wisdom. Or, in other words, good judgment comes from experience and experience comes from bad judgment. And...

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UNIDENTIFIED MAN: I - so teenagers manage to get this experience. Adults don't. Are we perhaps overreacting?

DOBBS: Hmm. There's a lot about this lately.

CONAN: David Dobbs, yeah.

DOBBS: There's several stories. There's one in the Times Magazine this past week and some others about the need to fail more in order to succeed, that by making mistakes you learn how not to not make mistakes. And every success has a string usually of flops or near misses or outright disasters behind it. So I think there's a lot to this. And, you know, parenting is really, really hard and part of the trick is getting the balance where kids can experiment but not hurt themselves. I'm thinking of my older son, the one who likes - used to drive fast. I'm sure he doesn't anymore.

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CONAN: Because you took his car away.

DOBBS: No, he paid $1,000 to lawyers, and he was without his car for a while. And every time I ever see him driving when he doesn't know I'm looking, he's driving really well.

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DOBBS: So I take faith that's most of the time. At any rate, it is important to get this idea - the balance right. And I can remember once him wanting to jump off something that was pretty high, but I don't think it was so high it would really hurt him. And he said can I jump? And I said you decide. And, well, he jumped, of course.

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DOBBS: But you do get these things. It's - the difficulty of this is that the risks are statistically small, but the bad outcomes can be horrifying, right? I mean, face it. When my son drove fast down the highway, there was a small single-digit chance statistically that he would wreck and die. If he wrecked, he was going to die. But it was a small chance, but the downside was horrific. And this is not an encouragement to drive fast down the highway, because if you do it enough, something will happen. But this is the dilemma of parenting and figuring out where the, you know, how bad it can get and stopping them there.

CONAN: Jay Giedd, you wanted to add something?

GIEDD: Yes. We've been very interested in educational implications of neuroscience, and it really - this is one of the key failures I think of the school systems is that the children are afraid to fail. At very young ages, they're worried about the grade. They don't want to take certain classes because they might get a bad grade. And I think one of the virtues of the Internet and online learning is that it's much easier to make mistakes if no one is watching. And in fact, the educational data has been quite encouraging in terms of the Khan Academy, this entire free math curriculum available to anybody with Internet access.

And that children learn much better when they're interacting with a machine that they don't feel ashamed to fail in front of. But it's really been hard for me to see again and again in the school systems how often fear of failure or fear of shame dramatically gets in the way of learning. And I think it's one of the things that, you know, we could really use the neuroscience to hopefully change that attitude. So it's not just adults that are, you know, afraid to fail. At very young ages in school, people are indoctrinated about it.

CONAN: Here's an email question from Kevin. How exactly do you measure the maturity of level of the brain and its different parts? Hormone levels, is that a good test?

CASEY: Well, hormones levels are very difficult to measure. And in terms of the brain, we're all using very different methods. I think what all the scientists have decided is the more information you can possibly come up with, the better.

For some reason - I know I do brain imaging - but for some reason, even in major decisions in the courts, even though the judges are Supreme Court justices, could tell you that they recognize that adolescents aren't engaging in fully developed behavior. When you see brain pictures, for some reason, it makes it much more empirical or believable. And so, I think in many ways, combining the behavior and the brain science together is very, very important and informative. Do you want to add on that, Jay?

GIEDD: Yeah. I think the answer to it in a negative, it's not size. In terms of maturation, isn't getting bigger, it's getting more specialized and more connected. So the different parts of the brain can be look at like letters of the alphabet. And as they grow up from a baby to a child, those letters are formed into words and then those words to sentences, those sentences into paragraphs.

And one of the more recent changes in our field has been this notion of graph theory, derived from the Internet and physicists with graphtic(ph) and all these different fields, but trying to measure this idea of connectivity, how our brain becomes more integrated because that's what changes during development. There's this kind of old notion that bigger is better and let's just, you know, the way brain - or see how big it is, and that's proved to be completely the wrong path.

CONAN: They always do it on "CSI."

GIEDD: Yes.

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CONAN: We have another question at the mic here in the auditorium.

MOLLY CONNORS: Hi. I'm Molly Connors. I'm a freshman at American University. And my question is, how does the societal curiosity about drugs and alcohol affect or increase the sense of risk and novelty already inherent in teens? I mean, it kind of creates this perfect storm of invincibility and risk factors that - seems to intensify. So what do you guys think about that?

CONAN: In the piece, David Dobbs, you said even people who, as adults, do not drink a lot, do as teenagers.

DOBBS: Many of them do, right. Many people who are perfectly reasonable imbibers, later on, drink too much when they're younger. This is something I'm not sure is a brand-new danger, that people would do this. What often makes it dangerous is what are they going to do once they've had too much to drink? And, unfortunately, the answer is, often, they end up getting in a car, partly because that's the only way to get to the party. I don't know if I have a great answer for that. I think we'll always have that problem and the struggle, as a society and also as individual parents, to try to, you know, corral and temper the environment so that the consequences aren't grievous.

CONAN: Now let's get another caller in. This is Harvey, Harvey with us from Oakland.

HARVEY: Yeah. I'd like to say, when I was a teenager, what we did, it was a little bit out - off the wall was comparatively tame. I lived in New York. We would go to the RCA Building, which, like, the third tallest building in New York with 77 stories. It had a observation deck on the upper floors, and they charge, like, five or dollars. But in order not pay that, we would sneek into the fire stairs and climb the 77 stories all the way up to the top. And, you know, so that was what we did for fun there.

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CONAN: And so, other than very well-developed calves

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HARVEY: I imagine these days in the post 9/11 world, the door would be locked on the fire stairs. At least we hope it would be.

DOBBS: There's an app for that now.

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CASEY: But also, just to build on that, by the time you got up 77 flights or what it is, you were pretty tired. And many times the adolescent psychologists have been talking about, how is it that we can build strategies so that the adolescent, instead of in the heat of the moment, makes one of these risky decisions can take a deep breathe in ways in which we can do that? So if you took many, many deep breathes

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CONAN: On alternate floors, perhaps. Harvey, thanks very much for the call.

HARVEY: Thank you. Bye.

CONAN: We have another question here, from the audience.

JEREMY: Hi. My name is Jeremy. And I wanted to ask, how does lack of sleep factor in risk-taking, because I'm home schooled and, like, I slept in until, like, 10:30 this morning.

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JEREMY: Actually got yelled at because I need to get out of bed to get here. But normal teens that go to public school get up at like, six and go to bed, like, 11 or even later, like... And a teenager needs, like, as much sleep as a two-year-old, so that's got to be a factor in there.

CONAN: Like - I'm sorry. Dr. Giedd?

GIEDD: Yeah. Thanks for bringing it up, because it's a huge, huge topic in terms of there is a strong biology to becoming of a night owl and less of a morning lark through that the teen years - 40 percent of U.S. teens, randomly selected, will have sleep deprivation, which you can measure by EED, 45 percent in Japan. And it's getting worse in terms of the Internet always open. My age at midnight or something, the eagle flew and there was taps and the TV went down, I think. But nowadays it, you know, it's constant stimulation, you know, it's 24/7. And the more time-saving devices that people have, the less time they save, and that's actually literally been looked at. And so lack of sleep increases your risk-taking, it decreases your attention. It hurts your driving performance. I mean, there's so many variables tied to sleep.

And you're exactly right. I mean... But school performance, as well. Several communities have tried to make their school start time later, and everything goes better, grades go up, parents (unintelligible) teacher. Everything imaginable goes up. But it's more expensive and it throw off the bus schedules and such. But it's a very, very important, insightful question, because it's a - it's bad and getting worse.

CONAN: We're talking about the adolescent brain with David Dobbs, a science writer, author of "Beautiful Brains," a current cover story in National Geographic. You just heard Dr. Jay Giedd of the brain imaging - chief of the Unit on Brain Imaging at the Child Psychiatry Branch of the National Institute of Mental Health. Also with us, Dr. B.J. Casey, she's the director of the Sackler Institute for Developmental Psychobiology, and professor of developmental psychobiology at the Weill Cornell Medical College. You're listening to TALK OF THE NATION from NPR News.

And let's go next to Marcia, Marcia or Marcia?

MARCIA: It's Marcia.

CONAN: Marcia in Clovis, California.

MARCIA: Thank you. Thanks for taking my call. It's fun to hear this. I was sitting last night reading the article and one of my teenagers have perched on the chairs with hearing and everything. So, yeah, when I called in I mentioned - I'm a mother of seven three are in their 20s now, and four are teenagers, as we speak. And the interesting thing to me is the spectrum I mean, parenting changes because you're relax when you get year older, but - and don't get so stressed out, but it's just really hands-on. And I guess what I wanted to address was the fact that when you talk about corralling and their impulses in that way.

But what I've noticed as a parent and watching the many friends of our teens as they went through this adolescent angst, was that parents tend to back off when these kids need them most. Right when they hit 10, 11, 12 and everybody is out there experimenting, these kids learn very quickly the sophistication. They know how to model sophistication, but it's not maturity. And the parents almost always back off because they're, oh, it's a relief, I don't have to do so much now - when these kids really need that hands-on communication and involvement.

CONAN: Well

MARCIA: And I'm wondering, how - I don't hear that addressed very much (unintelligible) corral us or work with it.

CONAN: So we have to - the question is being - how do parents know when to intervene and when not to intervene, when to back off and when to try a firmer hand is, I think, what Marcias is asking. B.J. Casey?

CASEY: So first, do you knight yourself every morning?

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MARCIA: Do I what?

CASEY: Knight yourself every morning?

MARCIA: OK.

CASEY: But I just want to respond to that, because I think it's a very important point. It's one Larry Steinberg also - who is mentioned in David's article - really underscores. And that is the importance of the parents being there and setting the limits and not feeling - I remember calling a parent and asking, if my son was, in fact, coming there. Because he said, oh, yes, we're all going to such and such's house. And how relieved she was that I called her because she said, my child would be mortified if I've done that. And I said, mortified or not, we, you know, the consequences of not knowing where you're child is is even worse. So it can be a bonding experience with other parents, too, to, sort of, re-enforce those forces.

CONAN: Dr. Giedd?

MARCIA: Well, my observation, too, is that your communication is key and you build that from birth. And that you suddenly jumped when you've got your 10 or 12-year-old and that issue arises. If we have that bond, that is what makes it work. And my - thankfully, my 25-year-old and (unintelligible) are saying, well, mom, you're always right. That

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MARCIA: that's really gratifying.

CONAN: They eventually say that. Dr. Giedd.

GIEDD: Yeah, I think, you know, part of the issue is when to intervene and the other is how to intervene. And several of the words that you just used, I thought, were intriguing because you mentioned, like, modeling and behavior. And it's very powerful in terms of - I think it's noteworthy that most humans have never read a single word since splitting from other hominids six million years ago, there's 100 billion humans, reading's 5,000 years old, so most humans that have lived and died have never read a single word.

Our brains are better at learning by example and by modeling. And so as a parent, we're often much more effective in just little things, how we treat our spouse, how we treat strangers, how we deal with the stresses and time management of our day-to-day life. So it's not always, sort of, sitting down and having these big, you know, talks. It's the little things every day that you're modeling. And I think it's, you know, good for us parents and - to realize, you know, in terms of we're always on. And whenever we're with them, that's how their brain is learning how to be an adult, how to take the next step. So I think, you know, what you've been doing and - as modeling, is the most effective thing that you're been doing.

CONAN: Marcia, thanks very much for the call and continued and good luck.

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MARCIA: Thank you. And teens are fantastic.

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GIEDD: I agree.

CONAN: All right. We can leave with that contentious thought. David Dobbs, at the end of the day, did all of this research make you a better parent, do you think?

DOBBS: Well, I'll at least tell myself it did. I think it, you know, to the extent, you can understand someone you are usually - well, some people, if you understand them, you know, just don't want to deal with it anymore. But, in general, if you understand someone better, you can deal with them better. And I felt I could understand my kids better that way.

And one thing that really struck me, given that they really want to hang out with their peers and not listen to authority, they want first-hand experience. You can offer to them as a parent if you talk about the lessons you learned when you were that age, rather than what they should do because you say so. I think that it's risky, but I think it gets a better response.

CONAN: David Dobbs, you can read his article on the front cover of this month's National Geographic. Our thanks as well to Dr. B.J. Casey and Dr. Jay Giedd and to the audience here on Grosvenor Auditorium at National Geographic. I'm Neal Conan. It's the TALK OF THE NATION from NPR News.

(SOUNDBITE OF APPLAUSE) Transcript provided by NPR, Copyright National Public Radio.

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