David Eagleman

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.

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

And they have real IQ deficits everywhere.

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 at that point.

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.

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 other things, like let's say accent, if you move to a new country before the age of 13, you typically won't have any accent in the new country.

But if you move after the age of 13, it's very difficult to sonically morph into that culture.

You'll always retain an accent.

So I use in the book an example of Mila Kunis and Arnold Schwarzenegger, both of whom were born

outside of america but they you know mila kunis moved here when she was um seven from ukraine she'd never spoken english before but she doesn't have you can't tell that she has any accent to her american english but arnold schwarzenegger moved here when he was 20 so it was too late for him to get rid of his accent so anyway the point is there are many critical windows that happen here with learning that said there are many things where you retain plasticity your entire life so

For example, your body as controlled by your motor system and your sensory system from your body, this is plastic your whole life.