Dr. David Eagleman

And so by the time they retire, let's say in their mid-60s, it's not really that fun for them to go out to parties and restaurants anymore because they can't quite hear.

And so there are all these converging reasons why their social lives shrink.

But it turns out

Social life is one of the most important things that we can do for our brains because there's an expression we sometimes use in neuroscience, which is that nothing is as hard for the brain as other people.

Because you never know what the other person is going to say and do and how they'll react emotionally and so on.

So you're constantly on your toes with other people.

And if you're not doing that anymore, that ends up being a problem.

Hmm.

But this is true for many reasons, actually.

OK, so the truth is your brain peaked at two, at the age of two, because that's when you get the most connections between neurons, between these cells in the brain.

You get this – at first, you're born with these 86 billion neurons, and they connect and connect and connect, and it finally becomes like an overgrown garden at the age of two.

And from there, you're pruning.

From there, you're taking connections away.

Now, it happens that that's not a bad thing.

That's a good thing because that's how you're resonating with the world that you are in.

you know, 21st century London and LA versus, you know, 10th century Mongolia, because you're just strengthening those pathways that resonate and you're getting rid of everything else.

Okay, fine.

But over time, your brain cells die.

You know, every time you hit your head on something or whatever, your brain cells are going down.

So in that sense, you've peaked, but your crystallized intelligence that you've been building your whole life,