David Eagleman

And occasionally you'll find a child who's locked up by their parents and they're not talked to and they have terrible –

cognitive development.

They just don't develop correctly as in they can never get language.

They don't even know how to chew.

They can't see very far.

It's just a half-baked brain that never gets cooked all the way.

And they have real IQ deficits.

It turns out there are these things in brain development called critical periods.

And one of those is if you don't get enough exposure to language, lots of language in your first several years, you can never get language.

So often these children are rescued at some point and a whole horde of psychologists move in and give them lots of love and lots of training and language and things like that.

But it turns out it's too late.

You just can't even teach language at that point.

Plasticity diminishes with age, and it doesn't do it smoothly.

It does it with these sort of punctuated moments.

So you've got, yeah, these critical periods for lots of different things.

So for example—

learning language you have to do in the first, let's say four or five years.

If you're not exposed to language, you just can't get it.

But, but, but, but other things like, let's say accent.

Um, if you move to a new country before the age of 13, you typically won't have any accent in, you know, in the new country.