Wednesday, February 23, 2022

Maturity At 25

Scott Alexander at Astral Star Codex, as usual, is the public intellectual who decides to look at whether this rather universally-held idea that the brain does not fully mature until age 25 is in fact true. As Alexander often does when developing his case, he tries rather obviously to force himself not to draw premature conclusions.  But you can tell quickly it has occurred to him that this idea is a myth and he wonders whether he will be proved out. I appreciate the effort he makes, telling himself not so fast. 

I believe we like the idea because it accords with what we see, or think we do.  A boy will run up and leap over a fence if his brain gives the assessment "I can make it nine times out of ten.  It'll be cool." After a few falls and failures that slides back to "I can make it 99 times out of 100" and eventually 999 times out of 1000, which we call better judgement. Eventually one gets to the point of "Wait.  Why am I jumping over fences at all, unless there is some need (or perhaps for training, or to test oneself for an upcoming trek across terrain.  Better to learn that here where the ground is softer and I'm closer to the car.)?"

But the data Alexander references shows that the brain parts of development are complete at about age 15 and then steadily decline throughout the lifespan, with no identifiable peaks or breaks at 25. As we don't think of 15-year-olds as showing the best judgement among us, that seems odd. We take fewer risks from that point on at a steady pace, as with jumping over fences. We do not hit some optimum of survival-based judgement at age 25 and then hold that until senility. At least, our brains don't.

Let me propose that our perceptions are guided by something else: the optimal level of risk-taking in our current culture occurs a few more years after the end of puberty than it did fifty or a hundred years ago, and as complicated and technological civilization has developed, the number has been slowly rising for a long time.  For the bulk of human existence, the amount of risk-taking we show at 15 has been about the right amount for perpetuating ourselves. If that's the case, then getting them "safely" married off by that time is a good strategy, fully acknowledging their sexual impulsivity while also insisting on an awareness that they must "use their Wise Minds," as the DBT phrase goes, rather than just do whatever comes into their...uh, heads.

It's a fun article to contemplate, as mythbuster articles by objective people usually are.


james said...

While "young hotheads" have been the bane of councils for-nearly-ever, most times and places have shoveled real responsibilities on their young. Mowing the lawn isn't quite as important as chasing the birds out of the rice field or taking care of the baby while mother is sick. We seem to have done less of that.
In our household we had chores, and once we had a yard we had a garden, with chores in that, but nobody was going to die if the chore didn't get done.

Christopher B said...

In regard to your explanation of the myth's origin, I wouldn't discount demographics. Eighty-odd years ago we were handing very technically sophisticated equipment for the time to men in their late teens to early twenties and expecting them to use it in extremely stressful situations. Similarly, some very young men were given enormous command responsibility. Francis Gabreski, the WWII and Korean war fighter ace, was a squadron commander and leading group level combat missions in WWII before he was 25 years old. The Boomer generation created an enormous overhang of people that made it possible to extend adolescence for some up to their mid-twenties in a way that we couldn't before, and may not be able to in the near future. As james alluded, stories of pre-teens performing responsible tasks in the 19th and early 20th centuries is likely because everybody else was doing something even harder and more dangerous. Anecdotally, driver's ed for my class in the late 1970s was largely a formality because most everybody had been operating vehicles and farm machinery since their early teens, or before. That might still be common now but the number of kids involved is much lower.

Grim said...

I think the problem is the assumption that excellence of the brain is related to a reduction of risk-taking. My guess it that risk taking is one of those bell-curve features, where high risk-taking is a feature of the tails and low risk-taking of the bell.

A person of moderate intelligence learns the prevailing theories of the wise, and is pleased then to stick to them. They allow him or her to appear intelligent by repeating what intelligent people say, and not to appear foolish by never veering from these things. A person of low intelligence may be incapable of understanding the theories, or ready to reject them for poor reasons; they may also take risks that are unwise, such as drug use and such.

It is the most intelligent, though, who take the biggest risks. Having understood the theories, they look for flawed assumptions or failures to grasp reality; and then they take the risks of rejecting the theories and trying to formulate a better way. Einstein famously did this by, having noticed that the basic physics of his day was not really working, returning to Plato and reconsidering the whole problem anew. Aristotle generally begins by laying out what the wise have said about a problem, explaining why each approach is wrong, and then trying to chart a new course.

I would say that the issue with maturity is much more one of having weight put on one's shoulders, or not. I noticed in China that young people in their 20s seemed almost infantile, carrying plush toys around and so forth; but their Confucian system concentrates power and authority among the old. A man of twenty here might be a Marine, or on his own learning a trade; or he might be living in his parents' house, but contributing to the family income. Alternatively, they might drift aimlessly through college and grad school, and not really assume any responsibility of weight until their 30s, 'putting off marriage and kids until I've finished school' and dragging school out as long as possible.

Now I haven't yet applied more than empirical observation to that theory, but if I were going to try the case that's where I'd look. The brain may be formed at 15, but it is the character that matures, and it is bearing weight that matures it.

Assistant Village Idiot said...

Just to reassert what my view is, reduction in risk-taking is not necessarily a brain excellence. Raven's Matrices IQ peaks at 16-17. Less physical risk is a brain excellence for the individual in the sector of this society that becomes the elites (though the tech wizards and entrepreneurs are outliers as well). Playing by the (new) cultural rules is the way to general UMC money and success. But it has its own risks, as those who hew too closely to those cautions can wash out entirely. They don't get shot or break their necks or starve, but the risk that didn't pay off turns out as you describe: dependent, unsuccessful, low status. And those trained on higher risk tolerance begin to pass them.

I would offer that a major problem for women in this generation - because as women's rights and opportunities have increase the risks and benefits change a little every decade, and not everyone catches on - is that the concept of finding a niche that has reliable food, shelter, and an approving community, yet still being regarded as mostly a failure to your family and the culture you grew up with, is brand new in the feminine experience. No one was trained for that. It began in my generation, of women earning disapproval for not "making something of themselves" despite great potential. I think it is full force now, perhaps even affecting the women of the elite classes more than the men. Unexpected.