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 M. Sapolsky holds degrees from Harvard and Rockefeller Universities and is currently a Professor of Biology and Neurology at Stanford University and a Research Associate with the Institute of Primate Research, National Museums of Kenya. His most recent book is Behave: The Biology of Humans at Our Best and Worst.
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.
A recent study gives new meaning to the saying "fake it 'til you make it."
- The study involves four experiments that measured individuals' socioeconomic status, overconfidence and actual performance.
- Results consistently showed that high-class people tend to overestimate their abilities.
- However, this overconfidence was misinterpreted as genuine competence in one study, suggesting overestimating your abilities can have social advantages.
Is this proof of a dramatic shift?
- Map details dramatic shift from CNN to Fox News over 10-year period
- Does it show the triumph of "fake news" — or, rather, its defeat?
- A closer look at the map's legend allows for more complex analyses
Dramatic and misleading
Image: Reddit / SICResearch
The situation today: CNN pushed back to the edges of the country.
Over the course of no more than a decade, America has radically switched favorites when it comes to cable news networks. As this sequence of maps showing TMAs (Television Market Areas) suggests, CNN is out, Fox News is in.
The maps are certainly dramatic, but also a bit misleading. They nevertheless provide some insight into the state of journalism and the public's attitudes toward the press in the US.
Let's zoom in:
- It's 2008, on the eve of the Obama Era. CNN (blue) dominates the cable news landscape across America. Fox News (red) is an upstart (°1996) with a few regional bastions in the South.
- By 2010, Fox News has broken out of its southern heartland, colonizing markets in the Midwest and the Northwest — and even northern Maine and southern Alaska.
- Two years later, Fox News has lost those two outliers, but has filled up in the middle: it now boasts two large, contiguous blocks in the southeast and northwest, almost touching.
- In 2014, Fox News seems past its prime. The northwestern block has shrunk, the southeastern one has fragmented.
- Energised by Trump's 2016 presidential campaign, Fox News is back with a vengeance. Not only have Maine and Alaska gone from entirely blue to entirely red, so has most of the rest of the U.S. Fox News has plugged the Nebraska Gap: it's no longer possible to walk from coast to coast across CNN territory.
- By 2018, the fortunes from a decade earlier have almost reversed. Fox News rules the roost. CNN clings on to the Pacific Coast, New Mexico, Minnesota and parts of the Northeast — plus a smattering of metropolitan areas in the South and Midwest.
Image source: Reddit / SICResearch
This sequence of maps, showing America turning from blue to red, elicited strong reactions on the Reddit forum where it was published last week. For some, the takeover by Fox News illustrates the demise of all that's good and fair about news journalism. Among the comments?
- "The end is near."
- "The idiocracy grows."
- "(It's) like a spreading disease."
- "One of the more frightening maps I've seen."
- "LOL that's what happens when you're fake news!"
- "CNN went down the toilet on quality."
- "A Minecraft YouTuber could beat CNN's numbers."
- "CNN has become more like a high-school production of a news show."
Not a few find fault with both channels, even if not always to the same degree:
- "That anybody considers either of those networks good news sources is troubling."
- "Both leave you understanding less rather than more."
- "This is what happens when you spout bullsh-- for two years straight. People find an alternative — even if it's just different bullsh--."
- "CNN is sh-- but it's nowhere close to the outright bullsh-- and baseless propaganda Fox News spews."
"Old people learning to Google"
Image: Google Trends
CNN vs. Fox News search terms (200!-2018)
But what do the maps actually show? Created by SICResearch, they do show a huge evolution, but not of both cable news networks' audience size (i.e. Nielsen ratings). The dramatic shift is one in Google search trends. In other words, it shows how often people type in "CNN" or "Fox News" when surfing the web. And that does not necessarily reflect the relative popularity of both networks. As some commenters suggest:
- "I can't remember the last time that I've searched for a news channel on Google. Is it really that difficult for people to type 'cnn.com'?"
- "More than anything else, these maps show smart phone proliferation (among older people) more than anything else."
- "This is a map of how old people and rural areas have learned to use Google in the last decade."
- "This is basically a map of people who don't understand how the internet works, and it's no surprise that it leans conservative."
A visual image as strong as this map sequence looks designed to elicit a vehement response — and its lack of context offers viewers little new information to challenge their preconceptions. Like the news itself, cartography pretends to be objective, but always has an agenda of its own, even if just by the selection of its topics.
The trick is not to despair of maps (or news) but to get a good sense of the parameters that are in play. And, as is often the case (with both maps and news), what's left out is at least as significant as what's actually shown.
One important point: while Fox News is the sole major purveyor of news and opinion with a conservative/right-wing slant, CNN has more competition in the center/left part of the spectrum, notably from MSNBC.
Another: the average age of cable news viewers — whether they watch CNN or Fox News — is in the mid-60s. As a result of a shift in generational habits, TV viewing is down across the board. Younger people are more comfortable with a "cafeteria" approach to their news menu, selecting alternative and online sources for their information.
It should also be noted, however, that Fox News, according to Harvard's Nieman Lab, dominates Facebook when it comes to engagement among news outlets.
CNN, Fox and MSNBC
Image: Google Trends
CNN vs. Fox (without the 'News'; may include searches for actual foxes). See MSNBC (in yellow) for comparison
For the record, here are the Nielsen ratings for average daily viewer total for the three main cable news networks, for 2018 (compared to 2017):
- Fox News: 1,425,000 (-5%)
- MSNBC: 994,000 (+12%)
- CNN: 706,000 (-9%)
And according to this recent overview, the top 50 of the most popular websites in the U.S. includes cnn.com in 28th place, and foxnews.com in... 27th place.The top 5, in descending order, consists of google.com, youtube.com, facebook.com, amazon.com and yahoo.com — the latter being the highest-placed website in the News and Media category.
If you thought your mother was pushy in her pursuit of grandchildren, wait until you learn about bonobo mothers.
- Mother bonobos have been observed to help their sons find and copulate with mates.
- The mothers accomplish this by leading sons to mates, interfering with other males trying to copulate with females, and helping sons rise in the social hierarchy of the group.
- Why do mother bonobos do this? The "grandmother hypothesis" might hold part of the answer.
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