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When we asked Robert Sapolsky what he might like to write about for the Nautilus Turbulence issue, he responded, “adolescence.” We had to laugh because the idea just seemed so perfect. Is there a more turbulent time in our lives? But is adolescence really a demarcated period in human life, biologically speaking, or just a modern cultural construct created, seemingly, by Mountain Dew? In fact, teens are their own beasts. Or their brains are. “The adolescent brain is not merely an adult brain that is half-cooked, or a child’s brain left unrefrigerated for too long,” Sapolsky said. As he explains in his Nautilus essay, “Dude, Where’s My Frontal Cortex?,” the teen brain, for all its famous downsides, such as a sullen love for Morrissey, is a necessary stage in human development’s slow dance, an incubation time for social intelligence.
Sapolsky built his career on a facet of turbulence: stress; in particular, stress-related diseases in Savanna baboons. At age 21 he ventured to Kenya to study a troop of baboons. He would return to Kenya for more than 30 years to detail the troop’s lives and families. The bookish kid from Brooklyn whose rebellion against his religious upbringing took the form of, well, “I wanted to be a mountain gorilla,” matched his fieldwork in primatology with lab work in neuroscience. Today, with best-selling science books like A Primate’s Memoir and Why Zebras Don’t Get Ulcers, as well as a MacArthur Fellows “Genius Award,” behind him, Sapolsky is a professor of biology, neurology, and neurosurgery at Stanford University.
For somebody who has happily spent a part of his life in jungles, Sapolsky lives in what has to be the most appropriate place in San Francisco, a tiny hillside neighborhood under a grove of tall redwood and eucalyptus trees. In a clearly well-lived-in dining room, near a piano on which stood a big and slightly ragged toy stuffed impala, Sapolsky sat with Nautilus for hours of conversation about turbulence, teens, and what the Internet is doing to our brains. Anybody who has read Sapolsky’s books knows him. The humane and witty writer, whose deep knowledge glides personably across the page, with just the right dash of sarcasm, is the man himself in person. Ask him a question and he loves to tell you a story.
Is there a period in human development when we have a “teenage brain?”
How would you explain teenage brain chemistry to parents?
How would you describe yourself as a teenager?
Is the intensity of teen experiences what causes them to stick with us?
What’s the evolutionary purpose of having a teenage brain?
What’s the purpose of breaking free of our genes?
Neurobiology sometimes seems so reductive. Do you worry about that?
I know this sounds like a dumb question, but what is stress?
What’s the price we pay for stress?
What is the flood of online information doing to us?
So is the Internet making us ill?
What’s the best way to manage stress?
Do online social relationships help or harm us?
What would you be if you weren’t a scientist?
Interview Transcript
Is there a period in human development when we have a “teenage brain?”
That’s a great question because there is even the issue that has been raised as to whether adolescence is “for real” in a biological sense. I mean, there’s plenty of cultures where essentially, you know, you’re married off to somebody when you’re 13 or some such thing, and all you are is like an adult with acne, that it’s not a special stage. And the suggestion that this is something that the West kind of invented, dealing with the fact that there’s now viewed as a delay between when one starts one’s main occupation, when one finishes education, and at the earlier end when the hormones start. Ah, we’ll call this magical period in between adolescence. So if it’s just an artificial construct, everything the brain is doing during development should just be in a smooth curve like this, where somewhere arbitrarily oops, that’s what we call adolescence is starting. Made-up concept. But that’s not what you see, because it is distinctive.
Parts of the brain are pretty much going full bore by the time you’re a year old, 5 years old. There’s parts of the brain, the limbic system which is involved centrally in emotion, which are pretty much all there by the time adolescence is starting. Then another distinctive feature of adolescence, which tells you it’s not just this: The hormones start. So what’s the frontal cortex doing there? The easiest picture would be if it’s the one that’s just sluggishly going on. That’s not what you see though. Interestingly, by the beginning of adolescence your frontal cortex is bigger than it’ll be as an adult.
Okay, what’s this about? This turns out to be this incredibly cool thing that mammalian brains evolved, which was, at least during fetal development, you make more neurons than you actually need. And what you do then is you run a wiring competition, and the neurons that don’t wire up optimally, you get rid of them. And during normal fetal development, a huge number of neurons are killed in this non-diseased, very controlled sort of way and clear them out of there. What are you doing? You’re pruning down to your sort of mean, lean neural circuitry. What the frontal cortex is about is, it doesn’t get to that point until you’re about 13 years old, that point of having the maximal number of neurons, and then what adolescence is about is pruning it away.
So it’s a very distinctive stage and it’s one where the problem isn’t you don’t have enough frontal cortex, you have an excessive, discombobulated, inefficient, poorly wired-up neurons in your frontal cortex. What adolescence is about is by trial and error, honing a frontal cortex that is going to be more optimal by the time you’re 25.
How would you explain teenage brain chemistry to parents?
How should one think about the chemistry of it? You’ve got the part of the brain which for a living sits there and says, “I wouldn’t do that if I were you;” “Stop and think about what happened last time;” “This is going to feel great in three seconds but you might very well regret this for the rest of your days.” It’s not fully functional yet. You’ve got this emotive part of the brain, the limbic system, that’s going full blast. You’ve got hormones thrown in there. And hormones not just in the, oh, torrents of hormones right around puberty, you’ve got a lot of oscillations of them. I mean a defining feature, if you were female, female primate, is your reproductive hormones oscillate all over the place during one’s point of ovulation, menses, back and forth. When you’re just hitting puberty, for the first couple of years of so you’re not even ovulating a certain percentage of the cycles, so you have fluctuation and then flat low and then fluctuation. So you’re having fluctuations in the fluctuations. It’s all over the place. And those hormones have tons of effects in the brain.
Probably the best way to thinking about sort of this turbulence of adolescence is this neurotransmitter dopamine. Dopamine, a totally cool neurotransmitter. It’s centrally involved in pleasure. Cocaine works on the dopamine system. What people have realized it’s not so much about pleasure; it’s about the anticipation of pleasure. It’s about the pursuit of pleasure, which is so much more addictive than the pleasure itself. Interesting neurobiology backing that up.
So what’s dopamine doing in the adolescent brain? Dopamine having to do with this reward stuff. Oh, is there is so much more of it than in an adult? No wonder they’re bonkers. Oh is there so much less and they just need that much more of an experiential oomph to get the same rise? No, the average levels are the same. What you’ve got is a different dynamic pattern. Beautiful studies. Okay, take an adult and you put them in a brain scanner and you can see how active this dopamine reward system is and you give them some task and they get a little reward and the dopamine system goes up a little bit. Give them a medium size, it goes up medium; big reward, it goes up all the way. Makes sense. Stick a teenager in the brain scanner. Give them the medium-sized reward and it goes up the same as you would see in the adult. Give them the big reward, it goes through the roof. Give them the little reward, does it not go up, quite…? It goes down and drops below where it started! For a teenager, a small reward is deprivation. The highs are higher, the lows are negatives or aversive. You’ve got the central neurochemistry there that’s just this gyroscope, completely out of control. That really central to what’s it about.
How would you describe yourself as a teenager?
Well, when I was a teenager I was terribly bookish. I was very studious. I had a pathological need to cross my Ts and get various adults to pat me on the head. My adolescent rebellions took the form of, if anything, passive aggressively doing what was asked of me but doing it ten times more than what was asked of me, so that eventually they’d have to beg me to stop. … Studying at the cost of socialization. I was raised in a very religious orthodox setting and right around the point where I decided I didn’t believe a word of this anymore, rather than refusing to do prayers, I just upped the volume of them and upped the frequency and upped the ritualism to the point that I had to be sort of suggested that, “It’s wonderful, but maybe it can get out of hand a little bit.” So I did sort of a paradoxical intervention with my parents. … Oh, if you’re like sufficiently orthodox in kind of the brand of Judaism I was raised in, there’s like prayers for everything you can do there, and if you like in the name of great devotion and honoring all the strictures you were raised in that you bring just everything to a halt every eight seconds because the rabbis suggest that… This turns out to be enormously irritating to parents and that much more so because they really can’t get you on anything there. So that’s what my adolescence was like.
Is the intensity of teen experiences what causes them to stick with us?
Well, yup. Part of it is the intensity. Adolescence amid everything else, is also characterized by, “emotions are felt more intensely,” and if you don’t believe an adolescent when they tell you or if you don’t believe it back when you were, stick someone in a brain scanner and show a picture of a scary face, a part of the brain called the amygdala activates and in an adolescent, it activates more. It activates longer. Parts of the brain having to do with responding dopamine to a pleasurable stimulus, bigger, longer, in the same sort… So the emotions are more intense and the formative aspects of it. That’s when you’re in your first window of really developing your own tastes where the most like important fact in the entire world is for you to communicate to the universe how different you are from any generation that came before you—and especially your parents—and it’s defined then.
Some misanthrope of an adolescent or early adult shows up and invents an entirely new cultural style and you’ve got a Stravinsky or you’ve got an Elvis or whatever, and your whole generation identifies with it and then 30 years later you’re sitting there and saying, “Well, if this music was good enough when we were defeating Hitler or liking Ike or sleeping together at Woodstock, it’s certainly still good enough now; and forget whatever garbage these 18-year-olds are listening to—I know what’s good music.” So a mechanism for why the novelty comes roaring in adolescence or early adulthood, and this is one of the mechanisms for why that window seems to close down afterward—this peer identification. That being said though, a rat, an adult rat, that’s not willing to try a new food is not doing it because that rat feels more connected to its fraternity bros and this is the stuff we ate back when so this is what I’m going to eat forever. There’s something much more biological going on there as well.
What’s the evolutionary purpose of having a teenage brain?
Great question. So why should it be this way? If you’re of a certain evolutionary biology bent, what you’re basically asking is what’s the adaptive advantage to adolescence, to the frontal cortex being delayed in its maturation? One possible answer is there’s no adaptive advantage, that this is an unavoidable aspect of brain development. Frontal cortex is incredibly fancy. You want to wire up your olfactory system, that one’s pretty much in place by the time you’re three days old. You want to wire up the frontal cortex, maybe that’s a 25-year building project. Maybe adolescence is just this emergent, epiphenomenal hiccup that comes from the fact that this is just the biggest building project your brain has.
I don’t find that one very convincing because the frontal cortex, you’re not using different building blocks than the rest of the brain. It’s the same types of neurons, it’s the same neurotransmitters, it’s the same layered structures in the rest of the cortex. It’s not that much harder of a building project. It shouldn’t take five times longer to wire it up than other parts of the cortex. So I don’t think it’s just baggage that emerged from how hard it is to build a frontal cortex.
So what might be the adaptive advantage? One thing that immediately comes to mind is oh, there’s something adaptive about teenage turbulence. There’s something enriching, there’s something—that’s where our new culture comes from, that’s where our new inventions came from. No doubt, you know, the person who invented the wheel had a horrible problem with acne at the time, and was 17 and figured this would get them laid or who knows what? Maybe, the advantage of adolescence has been the creativity, the generativity of adolescence. So that’s kind of cool.
I’m skeptical about that one though because the evolutionary behavior isn’t that organisms behave for the good of the species. Organisms behave to pass on more copies of their genes and adolescence is the time of life where your adolescent behavior is far more likely to have you break your neck and not pass on copies of your genes than for the adolescent turbulence to facilitate that process.
What I’ve been thinking might actually be going on is that adolescence is something unavoidable that emerges not because it’s so cool and adaptive, but because the adaptive thing is wait a long, long time before you have fully wired up your frontal cortex. Why might that be the case? Alright, so we’re born with our genome, the combination of your mother and father’s genes, that wind up in that first fertilized egg and that’s it. That’s your genetic legacy. Every cell in your body is destined to have that exact same genome. That turns out not to be true in all sorts of interesting ways, but what that also means is that when you’re thinking about what genes have to do with the brain behavior, by definition critically, if the frontal cortex is the last part of the brain to develop it’s the part of the brain least shaped by genes, and most sculpted by the environment and experience. And I think basically the only way you can have a species that is as complex and socially resilient and socially context dependent and all those amazing things we do, the only way you can pull that off is to have a frontal cortex whose development just bears the imprint of everything you experienced along the way—in effect, that’s been freed from whatever extent the genes are deterministic, which is not very. I think ironically what the evolution of the frontal cortex has been about is genetic evolution to free it as much as possible from the straight jacket of genes.
What’s the purpose of breaking free of our genes?
Well, when you look at the sociology of humans, of primate species, when you look at evolution, when you look at anthropology, cross-cultural differences, etcetera—being smart is a useful thing evolutionarily. Primates definitely have an advantage over stickleback fish in terms of the size of their nervous systems. Having a good memory is good, learning a lot, motoric coordination. When you look at the really fancy stuff about social behavior and what determines “success” in sort of the broadest sense of the term, what it’s got to do is appropriate social behavior. You know in the human realm that’s that whole world of your social intelligence is a better predictor of how you’re going to do by all sorts of measures in life than your IQ. You look at a baboon and you ask, “Okay, a male baboon. What determines whether or not you wind up being the alpha in your troop?” Mostly, your muscle mass, how sharp your canines are, how aggressive of a son of a bitch you are. Okay, that’s got tons to do with whether you attain alpha-ship. What’s the predictor of who maintains it for a long time? It’s all social intelligence. It’s who you can intimidate without actually getting into a fight. It’s which coalitions you form and which ones you don’t go anywhere near. It’s which provocations you walk away from. It’s all about impulse control. And when you look at the really complex primates, success is really not about remembering that, “Oh four valleys over there’s a tree that’s going to be fruiting at this time of year; let’s go there this morning.” It’s the social intelligence stuff and what that’s all about is the frontal cortex. If you don’t have a frontal cortex that has been shaped by the subtleties and the idiosyncrasies of your immediate social world, you’re not going to be anywhere near successful of a primate. And I think that’s why it’s got to be the part of the brain that’s the last to develop. It’s got to be shaped by all that contextual stuff.
Neurobiology sometimes seems so reductive. Do you worry about that?
Absolutely. … Well, for one thing, because there’s a certain style of ideological laziness that makes one grab onto reductive explanations for behaviors. Here is the gene that explains. Here’s the hormone, the brain chemical, the childhood experience, the… Because reductive single explanations for behavior are just ripe for ideological misinterpretation, distortion, all of that. But off that political bandwagon, because reductionism doesn’t actually tell you a whole lot about how this stuff works. I mean reductionism is perfect for like telling you why your clock is broken. What you do is you break it down to its component parts. You find the part that’s got a tooth missing from the gear. I guess there’s not a clock on earth that works this way anymore, but your Renaissance clock. You fix the missing tooth, you put it back, you add the pieces back together and it works. The way to understand a complicated system is to understand its component parts. The way in which that steps away from the ideology is the component parts of the genes and the nerve transmitters and the hormones and the early experience. Okay, so that’s a more sophisticated version of reductionism. You got to be reductive about lots of different domains. But nonetheless, even that more multidisciplinary version of reductionism isn’t going to work because that’s not how complex systems work and humans are a complex system. You got these emergent non-linear chaotic properties. What’s that another way of saying? If you knew every individual’s genome and exactly which gene was active at which point, are you going to be able to predict who’s going to do what next? Absolutely not. If you added in knowing the levels of every hormone in their body at that point, if you added in… it doesn’t work that way. The reductionism breaks down because the reductionism breaks down in the same way that like a cloud that isn’t producing enough rain during a drought or something, the solution isn’t to study half the cloud and then get a research grant to study a quarter of the cloud and smaller, smaller pieces and finally understand the reductive basis of the non-rain and add it up together. That’s not how clouds work when they don’t rain. Humans are more like clouds than they are like clocks. We’re not reductive in that way, which is the case for any complex system.
I know this sounds like a dumb question, but what is stress?
Well, it’s actually a great question and like it’s virtually guaranteed at any conference of biologists who study stress that some grand old Pooh-Bah, emeritus guy is trotted out to give the first talk of the conference and the first talk is always going to be titled, “What is Stress?” where they’re going to conclude at the end that more research is needed, send me a grant. And I haven’t reached that point yet, fortunately, but I’m sure that’s in my future.
So what is stress? The answer is, it depends. It depends on what species you are. If you’re your average, off-the-rack mammal, what stress is about is somebody is chasing you intent on eating you or you are chasing somebody very intent on eating them. It’s a short-term physical crisis and the whole point of that stress response in the vast majority of species is, you get these changes in your body, various hormones and neural systems and, you’ve got this whole set of coordinated responses and what they’re designed to do is to save your neck in that circumstance, to shut off everything that’s not essential. You’re running for your life, thicken your uterine walls some other day, to deliver energy from storage places to exercising muscle to increase blood pressure and heart rate, to turn off growth, to turn off reproductive stuff, you know all of it’s built around solving the next three minutes or the next three hours. And in that regard, what stress is about is an external challenge to your homeostatic balance and what the body does at that point is incredibly conserved evolutionarily. You get essentially the same stress response, the same hormones if you’re looking at a primate, a fish, a bird, a reptile. This is ancient, ancient wiring.
So what’s stress? Then you get a different definition when you start thinking about smart social species like us. Stress can be, yes, somebody is very intent on eating you, the short-term physical crisis, but in addition, stress can be when you think you’re just about to have a crisis. And that could be true. You can have an anticipatory stress response, which is very adaptive. On the other hand if you think you’re just about to have one of those challenging crises, and that’s not really the case, it’s not true, and you think that way all the time, you’re being neurotic, you’re being paranoid, you’re being hostile, and you’re being profoundly human. I mean, sit down a hippo and try to describe why it’s possible to increase your heart rate by thinking about the fact that someday your heart is going to stop beating and the hippo’s going to have no idea what you’re talking about. And that’s the critical thing with us as humans. We can turn on the stress response—the same stress response as an animal running for its life—we turn it on for psychological reasons. And that’s the distinctive thing that does us in; that’s not what it evolved for. It evolved for dealing with a short-term crisis, yet we turn it on for 30-year mortgages. That’s where you pay the price.
What’s the price we pay for stress?
At its worst, there’s just virtually no organ system in your body that’s not thrown out of kilter in some way by chronic psychological stress. Big dichotomy is between whether stress causes disease or stress exacerbates pre-existing disease or—actually trichotomy, whether stress changes your behaviors in a direction that put you more at risk for disease. Evidence isn’t that great for stress causing disease but what it potentiates is all sorts of other pathologies. You’re on the edge of diabetes, insulin-resistant diabetes, adult onset, and what stress does is tell your fat cells, “What a great idea, being insulin resistant; get even more so.” You suffer from hypertension due to arteries that are not particularly clear. What does stress do? “Let’s increase blood pressure even more.” It exacerbates. At the behavioral end, what stress also does is, it makes you crave foods that are not good for you. It makes your self-discipline break down. It impairs functioning of the frontal cortex. You do things that are less prudent for your health. People make imprudent decisions. Their judgment gets worse when they are stressed. So you’ve got a whole realm. Cardiovascular disease, gastrointestinal, reproductive, function, immune function, memory, mood, vulnerability to depression and anxiety—all of these are areas that are vulnerable to chronic stress.
What is the flood of online information doing to us?
Okay, so one of the sort of key findings when looking at what is it that makes psychological stress stressful, for the same external unpleasantry, you feel more subjectively stressed, and you’re more likely to turn on the stress response if you feel like you don’t have control, you don’t have predictability, you don’t have outlets, you don’t have social support. Brilliantly clear studies showing things like an individual gets a mild shock every now and then, oh, their blood pressure goes up. Individual gets the same pattern of shocks, but ten seconds before each shock, a little warning comes on. They don’t get as much of a stress response. Oh, predictability is a good thing. Predictability about an adverse event that’s coming tells you how bad it’s going to be, when is it going to happen, how long is it going to last, predictability information is good, that’s a mantra in the field.
But, what you see is, what you don’t want is the wrong kind of information. Information about stuff you can’t change; information that’s overwhelming; information that suggests the uncontrollable should be controllable; information about what’s already occurred; information that’s superfluous; information about stuff long in advance. Take somebody who’s getting the shocks and they get the warning light half a second before—there’s no benefits. Ten seconds before, it’s helpful. Thirty seconds before, it makes things worse, because you’re sitting there for 30 seconds saying, “Here it comes, here it comes, here it comes.” Information predictability is great, but within a certain narrow range. Too much information and it’s just as stressful as too little, and what we specialize in in society, of course, is inundating ourselves 24/7 with information.
So is the Internet making us ill?
Well, I don’t know if quite to that extent, but I don’t think overall it’s doing great things. Yeah, we’re inundated with more information than we need. We’re inundated with more false choices than we need because we’re suckered very often into thinking that those choices will actually make a meaningful difference. If you can only get your head straight and pick which of the 27 different versions of gluten-free breakfast cereal, your life will be…you will die a happy person. “Oh, if only I can sort through this, what’s wrong? I’m so stressed that I can’t figure out what…” You know, we’re inundated with nonsense decisions, nonsense information. That’s not stress reducing. That’s stressful.
What’s the best way to manage stress?
One of the best forms of stress management out there is social support. Rat gets shocks now and then, if it can huddle with another rat that it knows and likes and they groom each other—not as much of a stress response. Same thing with primates, including us, like person is sitting there having some unpleasant scary medical procedure, a catheterization, blood pressure goes up. They get to sit there holding the hand of somebody they know and trust, doesn’t go up as much. Yes, social support is great. Writ small it’s great; writ large, the impact of social isolation on mortality is very, very well documented by now and sort of all the behavioral medicine on a certain level is influenced by that.
Okay, so social support is great, social support is great. When is it not great? When you mistake any intimate for someone who turns out to be an acquaintance; when you mistake having sustained social support with a series of one day or one night interactions; the whole world of the versions of socialization that people look for in our society that ultimately, doesn’t quite do it. But what’s interesting, and an area I’ve gotten increasingly interested in, is sort of social support as a stress management technique in a cross-cultural setting. And social support reduces stress in different ways and different cultures.
For example, you get people in the United States and when they’re stressed it’s good for them to get together with friends and what do they mostly do? They want to get together with a friend so they can bitch and moan about how awful their situation is. You get somebody from a collectivist society, and these are typically studies of East Asian populations, when they’re stressed they seek out social support of close friends. What do they do then? They try to get the friend to talk about their life and their problems as a means of distracting, as a means of you know reifying their relationship in this. We do totally different things in different cultures.
In individualistic cultures, like ours, you ask somebody, “Tell me about times that you’ve influenced somebody else? And tell me about times that somebody else has influenced you?” Westerners come up with much longer lists of times they’ve influenced somebody else. I am the captain of my own ship. Get East Asian populations, same thing, they come up with more examples of times they have been influenced by somebody else, talking about when you’ve influenced somebody as bragging, as standing out, as not belonging all of that. Now take the westerner and say “oh, so tell me about one of those in detail?” Time they influenced somebody else, terrific. Time somebody influenced them, they turn on the stress response. Having to admit that they are influenced, they are not this autonomous John Wayne figure of western individualism. Somebody from east Asia, get them to talk about a time they’ve influenced somebody else, they turn on the stress response, so the cultural stuff works very differently amid the general theme of social support is a good thing. But people vary dramatically, and not just by culture, as to what counts as supportive.
Do online social relationships help or harm us?
Well, this is for lots of scientists a $64 question. What’s this world that’s being created by online relationships? It’s easy for me, from my generational perspective to decide this is wildly artificial, distortive, narrow, a paucity of true connectiveness there. It’s clear looking at teenagers that that’s not the case in the slightest. Handful of studies looking at, for example, adolescents when stressed about something—I think it was somebody who just had to give a public talk or something, a kid, experimental setting—they can either hear their mother’s voice or get a text from their mother. The voice works better. There’s something more real there, so that suggests an artificiality. At the same time, studies are first coming out now suggesting that marriages derived from online dating are just as stable as are ones from traditional. You know, the jury’s out on all of it. It seems weird as hell to meet people, to know people exclusively online, but nonetheless without question, the grandfathers of the sociologist studying this now were studying back when. Well, what’s this mean that you can have a telephone relationship with somebody? Somebody you can be in love with can live on the other side of the country and you interact with them daily without actually seeing their facial expressions? I suspect it’ll wind up being exactly the same.
What would you be if you weren’t a scientist?
Well, obviously I’d be a gorilla. What else would I be? Basketball’s out. I don’t know. I’ve spent such a long time knowing I was going to do this someday. When I was in high school, I took one of those “Learn It On Your Own” courses in Swahili because I knew I was going to go study primates in East Africa someday, so I’ve spent such a long time like in this mindset and being very content throughout that I really haven’t spent a whole lot of time thinking about my road not taken. I’m pretty content with this one.
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