Joseph Henrich

So you want to see this as a dynamic pulse.

There were probably expansions and then collapses, another expansion, another collapse, right?

It's not one giant long march to victory.

Yeah, I think there's a cultural evolutionary dynamic that's part of this because languages will naturally diversify.

And then as that diversify, there's less contact.

People sometimes get inclined to marry endogamously.

And especially if there's enough people around locally, why go all the way over there?

And those people are getting more culturally different.

So they're seeming a little bit like outsiders.

And then, yeah.

Interesting.

Okay.

So the tough part that humans have always had is to stay unified because of the natural effect of geography and learning locally is going to tend to fragment us.

Yeah.

So before I get to solving the problem, I just want to sketch for the listeners that...

The question is, is why is this cumulative cultural evolutionary process that is so important for humans relatively uncommon in the natural world?

It seems like just our lineage.

I mean, there was a bunch of splinoff lineages, but now it's just us.

So to understand that is this idea that you just mentioned where you're imagining an increase in brain tissue that's going to be costly.

And I can put that towards individually figuring the problem out for myself, or I can put it into learning from others.