Joseph Henrich

Why has brain size been declining?

Well, the collective brain argument suggests that at a certain size, you'll begin farming off specialists.

Because there's a store of knowledge in the society, and we can all be generalists and learn how to do all the different skills.

But at some point, it makes efficiency sense for us to specialize in different skills.

In order for that to be the case, though, we have to have social agreements of some sort that allow us to trade or exchange things like that.

But then once we're specializing, we don't necessarily need as large a brain because we distribute the overall brain power amongst the society.

So it could be that we're becoming more of a superorganism.

And you see the same thing in ants.

When ants get specialized occupational casts, their individual brains shrink.

Well, they didn't say anything about intelligence.

They did use the polygenic score for education.

Yeah.

Yeah.

So, but there was no education 8,000 years ago.

Yeah, it's correlated.

Yeah.

But then the question is, is we don't know what goes into that, right?

Is that actually computational software?

Or, I mean, people do well in school because they stick to it and they can sit in the same place for long periods of time.

Well, there are IQ.