What makes the mannerisms of precocious child actors so adult-like?

I’m watching an 11-year-old actor on The Tonight Show right now, and it’s just plain creepy how adult-like his mannerisms are; there’s not even a hint of “kid” in the way that he talks, gestures, moves, carries himself, and so on. I’ve noticed this among most child actors in the past - current it-kid Dakota Fanning displays this in spades in interviews, and has since as far back as I am Sam.

Why? Is it something that’s cultivated in these kids through acting lessons and by acting coaches? Is it an inherent trait that causes these kids to be selected/cast in the first place? Is it the result of them constantly being around older people instead of socializing with kids their own age?

More likely it has to do with them not socializing with condescending adults. There’s a tendency to infantalize juveniles that’s really only come up in the last century or so.

If you’ve ever met a wee person that’s raised by parents that don’t “talk down” to them, you’ll note that their communication and deportment is way more sophisticated than your average kid. It’s nurture, not nature. It only seems creepy because we’ve been socialized to generally expect young people to be intellectually stunted.

Ever read the Alice books? The way Alice talked in those books was meant to represent an unremarkable Vitorian ten-year-old everygirl. She might not have all the facts, and she’s confused about trickier vocabulary sometimes, but it’s taken for granted that she’s able to engage her reason and have a sense about what is proper behavior, even when surrounded by madness.

That sort of demeanor is normal for someone that age, outside of the culture of bonsai-kiddies.

Deferred development has gotten so extreme now that we don’t blink when we see people edging up on thirty wearing short-pants, ball-caps, and pushing a skateboard. Go us!

Part of it might be that the adult behaviour and mannerisms are highlighted because you’re seeing them out of context - making it easier to scrutinise them on their own.

It might also be a touch of the uncanny valley phenomenon - it’s almost exactly what it’s supposed to be, but the small amount by which it falls short makes it more psychologically disturbing than if it had only been a poor imitation of what it’s supposed to be.

Maybe part of it is that they don’t fidget.

I totally agree its mom and dad, with perhaps a sprinkle of nature thrown in. I could see a perceptive young kid who is treated more like an adult than a child acting the way some kid actors do.

A friend of mine’s son is only 3, but already has adult mannerisms. He also loves to dress up in costumes and entertain people with skits and songs he composes on the fly (which almost sound like real songs). Nothing about how his parents raise him suggests to me that they are the source of this, and his brother (2) is clearly not like this. So based on my experience, at least some children are just naturally extremely precocious.