Kyle Harper

Infectious disease imposes a huge burden on the body.

the immune system is extremely metabolically expensive.

And so if your childhood is spent just fighting infectious diseases, you're going to struggle to invest energy and growth.

So there's a massive increase in the size of populations over the last 250 years.

And even though it's an even more complicated trait,

This improves people's cognitive abilities.

People are smarter.

Like, may not feel like it.

But – and I think it has rapidly leveled off.

But –

You know, people are more intelligent today than they were 100 years ago.

Their brains are better nourished and their bodies spend less time fighting pathogens.

So I think there's no doubt that pre-industrial populations, and again, populations, so you still have, you know, you still have your Isaac Newtons who whatever infected him as a kid didn't slow him down.

But at the population level, I think there's no doubt that not only were pre-industrial populations

This is just a total fact that we know from their bones.

But they probably also on average had sort of a lower distribution of cognitive abilities but with a big distribution.

Yeah, I mean obviously it didn't keep them from discovering some pretty amazing things.

So it couldn't have been completely destructive.

But that's one of the things that's interesting about the early modern period and the 17th, 18th century in particular is it's sort of this between period where –

where you have sort of the pre-industrial and the modern that are still like mixed together in these really interesting ways.