David Eagleman

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.

You can learn how to kiteboard or parachute or do any, you can learn all kinds of new stuff, take up a pogo stick if you want at any age.

But things like your visual system, that gets less and less plastic with time because it says, okay, I got it.

This is what the world looks like.

And it sort of hardens into place.

Yeah, well, so it turns out that we've got these sensors like our eyes, which are these two spheres in the front of your skull that pick up on photons.

And they have chemical reactions.

They pick up on photons and they send electrical signals back into the darkness of the brain.

And you've got your ears, which are picking up on air compression waves.

And it's a very sophisticated little machine.