[civilian]

The personality metrics they're using are the Big-5. The Big 5 has good test-retest scores (if you take the test a month apart, you're likely to get the same scores). Big 5 is used in a ton of psychological studies now.

If I had to bet on nature vs nurture, I'd place bets on nature. Separated twin studies seem to suggest genes are a strong determiner. And if you've ever met a kid who stubbornly prefers to be introverted or extroverted-- it often has nothing to do with how adults are treating them.

[jokoon]

https://en.wikipedia.org/wiki/Big_Five_personality_traits#Cr... quite a lot of critics in there

I don't dismiss it entirely, and humans don't really know enough about how the brain works on the mechanical level. The big 5 doesn't look very insightful.

[RoyalHenOil]

>And if you've ever met a kid who stubbornly prefers to be introverted or extroverted...

My mom says she had an inkling I would be introverted (like my dad) and my sister would be extraverted (like her) just based on our behavior in the womb. I was very calm and nonreactive, while my sister was a big kicker and very reactive to external stimuli. Those personality traits have indeed persisted through adulthood.

[Jach]

Most people are unaware of the separated twin studies and it shows.