Dr. David Eagleman

Why?

That's because as you get to be an adult, you've got a better and better model of the world.

You don't want to change everything.

You just change like, oh, I didn't realize there was that button on the coffee machine that did this new thing or whatever.

So you just change little bits at a time here.

We're in this really interesting situation in the history of our species where now we can do things like, hey, what if we just crank up acetylcholine?

Obviously, we've done lots of things with dopamine.

We always find when we tweak these things that it's complicated.

Just as one example, with Parkinson's, people have less dopamine, and so the medications are to crank up the dopamine.

What that led to, you may know this fascinating story, it's probably 25 years ago now, where

You know, observant clinicians noted that people on these Parkinson's medications were becoming hypercompulsive gamblers.

They were blowing their family's fortune on online gambling in Las Vegas and so on.

And what they realized is when you crank up the dopamine, that changes your risk aversion such that people were taking it.

So now it's a contraindication that's listed on the model.

You know, if you notice gambling, turn down the…

the amount here.

So anyway, whenever we start dialing these around, we always find things that are a little bit out of our predictive realm.

But the general story is that your brain's trying to put together this model of what's going on.

And as it gets better and better, it's doing less and less plasticity.

I do want to point out, though, that parts of the brain become less plastic and others stay plastic your whole life.