Dr. David Eagleman

Because you're doing so much fine motor activity with your fingers, with both hands.

In contrast, if you're a violinist,

You're only really doing that kind of detailed activity with one hand.

The other hand is just bowing.

And so you only get that activity here in one half of the brain for violinists.

So I can look at a brain and tell, hey, is the person a pianist or a violinist or neither?

I can tell just by looking at the visual cortex because you see changes in the brain based on...

What you do, for example, jugglers, people who play music, even you can tell us with medical students who study for final exams, you actually see changes in the distribution of their cortex.

Why would it be getting bigger?

The reason is the brain's devoting more real estate to that.

In this case, let's say we're talking about fingers on a piano or a violin.

The brain is devoting more.

There's more relevance to that.

And so more real estate.

So that you can do it better in the future?

Exactly.

The key about the cortex, this wrinkly outer part, is that it is a one-trick pony.

This is often overlooked because even this brain that I'm holding here is color-coded so that we think, oh, okay, that's clearly labeled this, that's clearly labeled that, and so on.

But in fact, it's all the same stuff and it can change.

So for instance, if you are born blind...