David Eagleman

It's called apoptosis, where it's not that they're dying because of injury or something and releasing inflammatory chemicals.

It's that they're saying, okay, I'm done here.

And they fold up shop and they carefully kill themselves.

And so this is a majorly important part of how the brain develops.

So it turns out that in the brain, no territory lies fallow.

Everything is going to get used.

And so we think about this area at the back of the head.

We think of that as the visual cortex.

But yes, if you go blind, it's no longer the visual cortex.

It gets taken over by hearing, by touch, by memorization of words, by lots of things.

because it's perfectly good territory.

Now, the territory I'm talking about is called the cortex, which is the outer wrinkly bit of the brain.

We have more of it in relation to our body size than anybody in the animal kingdom.

This is sort of the magical stuff that makes us really good at what we're doing.

So...

It turns out that cortex is a one-trick pony, which is to say it's not that this is fundamentally visual and that's fundamentally auditory and for touch and for controlling the motor system, but instead any of it can trade off with any other of it.

And so the really special thing with humans being live-wired is that we drop into the world half-baked,

And we absorb everything around us.

That's how you absorb your language, your neighborhood, your culture, your parents, your way of acting, your way of acting in the 21st century, and so on.

In other words, if you were born with exactly your DNA 1,000 years ago, you'd be a really different person.