supersadface Wrote:
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>
> I have a theory that I think I came up with about
> a person’s character. It seems to me that once
> you hit about 25 or so, most (but not all)
> people’s character is pretty much set. I think of
> it a bit like drying concrete - when you’re young,
> your character is pliable and you’re still
> learning lots and lots every day, and there’s time
> to change who you want to be. When you exit
> college, your character is hardening rapidly - you
> can change it, but you’re starting to decide who
> and how you want to be. Past a certain point, I
> think most people have decided to accept their
> character and aren’t interested in changing it
> anymore.
>
Yes, I’ve long had this theory too, with about the same age cutoff. Up to about age 25, people can “try on” different personalities a bit like they are changing their outfits and seeing what works. After about 25 or 26, the main values have set, and don’t really change nearly as often.
There is an exception, though. People can change through personal crises: deaths, health scares, career crisis, the collapse of a major relationship, creating another major relationship like marriage, parenthood, etc.. But it doesn’t change nearly as easily as before 25.
There is now brain research that suggests that the brain’s physiological adolescent period doesn’t actually end until - wait for it - 25 years of age. Which lines up fairly nicely with yours and my observation. After that, brain formation isn’t as rapid and the brain isn’t quite as plastic (in the adaptive sense).
Given that - for much of human evolution - most humans did not live much longer than 30-35 years (even in the US in 1900, it was only about 47-48), one can think that the brain did not need to evolve much past 25. The adaptive advantages gained by being permanently pliable may have been outweighed by the physiological cost of maintaining that adaptivity. Brain activity uses approximately 25% of total calorie intake. Making it more adaptive would require even more, because the neurons have to be more active and make new connections.
Now that we live substantially longer, it would be nice to be able to reprogram our brains to continue to adapt, but, alas, all we have is cannabis and LSD for that… ;-)