The teenage brain: Why some years are (a lot) crazier than others

Neurobiologist Robert Sapolsky explains how your first 25 years will shape the next 50.

ROBERT SAPOLSKY: Neurobiologically, the single most important fact about, say, a 20-year-old brain is the fact that almost all of it is already matured, fully wired up—myelinated, a jargon-y term for it. The reward dopamine system has been going full blast since somewhere around like early puberty. All of the brain is totally up to speed—except for the frontal cortex. Probably the most interesting fact about human development is that the frontal cortex is the last part of the brain to fully mature. It is not completely online until you're about 25 years old, which is mind-boggling to think about.

What does that explain? That explains why adolescents are adolescent in their behavior. The sensation-seeking and the risk-taking; the highs are higher and the lows are lower, because the steadying frontal cortical hand there isn't fully up to speed yet, and everything else is a gyroscope out of control. And that's where the impulsivity is from. And that's where the extremes of behavior, and that's why most crime is committed by people at a stage whose frontal cortex is not fully developed yet. That is why most people who do astonishing, wondrously self-sacrificial things don't have the frontal cortex that's fully in gear yet either, and it's not in a position to convince them yet, 'Ah, that's somebody else's problem. Look the other way.'

That's why young adults are exactly how they are. Because the frontal cortex isn't quite there yet, and what you have as a result is more adventurousness and more openness to novelty and more likelihood of seeing somebody who's very different as, in fact, not being that different after all. And more likely to grab a cudgel and smash in somebody's skull who happens to seem like a "Them". And everything, just the tone of everything, is pushed up.

One incredibly important implication of that is that if the frontal cortex is the last part of the brain to fully mature it means it's the part of the brain that is most sculpted by environment and experience—and least constrained by genes. And it's the most interesting part of the brain. Meanwhile, look at the other end of it. Look at 60-year-olds and what's going on there. If you are a 60-year-old human, or say a rat equivalent of a 60-year-old, you are far more closed to novelty than a 20-year-old, than an adolescent rat is. Take a rat, for example, and see at what points in life is it willing to try a new food. At exactly the equivalent of late teenage years, early adulthood, and then you're closed to novelty. Any species out there shows that pattern including humans. So a 60-year-old is resistant to change, is resistant to somebody else's novelty. A 60-year-old, unlike a 20-year-old, deals with stress in a very particular way. If you're 20, what stress management is about is trying to overcome the stressor and defeat it. If you're 60, what stress management is about is learning to accommodate what things you're not going to be able to change, and there's nothing you can do about the fact that your knees hurt like hell; it's accommodating, it's learning the difference between what you can change and what you can't.

If you're 20, there's nothing in the world you can't change. By the time you're 60, what intelligence is mostly about is crystallized, fact-based knowledge and crystallized strategies for dealing with that knowledge.

What a 20-year-old intelligence is about is fluid, improvising, changing of set, reversing of orders. All of that is a very, very different sort of picture. So 20- and 60-year-old brains and 20- and 60-year-old social worlds are remarkably different.

  • The human brain isn't fully developed until 25 years of age. Everything is there except for the frontal cortex, which is the last thing to mature.
  • An immature frontal cortex explains the spectrum of teenage behaviors: it's what makes adolescents adolescent, says Sapolsky. "The sensation-seeking and the risk-taking; the highs are higher and the lows are lower," he says. Teenagers are more adventurous and more heroic during this time—but can also be more violent and impulsive.
  • Because your frontal cortex is the last part to develop "it's the part of the brain that is most sculpted by environment and experience—and least constrained by genes," Sapolsky says. That's great news! Your adventure levels, openness, experience, and influences at 25 years old will shape who you are when you're 60.

VR experiments manipulate how people feel about coffee

A new study looks at how images of coffee's origins affect the perception of its premiumness and quality.

Credit: Escobar / Petit / Velasco, Frontiers in Psychology
Surprising Science
  • Images can affect how people perceive the quality of a product.
  • In a new study, researchers show using virtual reality that images of farms positively influence the subjects' experience of coffee.
  • The results provide insights on the psychology and power of marketing.
  • Keep reading Show less

    Is empathy always good?

    Research has shown how important empathy is to relationships, but there are limits to its power.

    Videos
    • Empathy is a useful tool that allows humans (and other species) to connect and form mutually beneficial bonds, but knowing how and when to be empathic is just as important as having empathy.
    • Filmmaker Danfung Dennis, Bill Nye, and actor Alan Alda discuss the science of empathy and the ways that the ability can be cultivated and practiced to affect meaningful change, both on a personal and community level.
    • But empathy is not a cure all. Paul Bloom explains the psychological differences between empathy and compassion, and how the former can "get in the way" of some of life's crucial relationships.
    Keep reading Show less

    Your body’s full of stuff you no longer need. Here's a list.

    Evolution doesn't clean up after itself very well.

    Image source: Decade3d-anatomy online via Shutterstock
    Surprising Science
    • An evolutionary biologist got people swapping ideas about our lingering vestigia.
    • Basically, this is the stuff that served some evolutionary purpose at some point, but now is kind of, well, extra.
    • Here are the six traits that inaugurated the fun.
    Keep reading Show less

    Godzilla vs. Kong: A morphologist chooses the real winner

    Ultimately, this is a fight between a giant reptile and a giant primate.

    Surprising Science

    The 2021 film “Godzilla vs. Kong" pits the two most iconic movie monsters of all time against each other. And fans are now picking sides.

    Keep reading Show less
    Quantcast