David Reich

And some people argue that humans are not even more intelligent than chimpanzees.

at some fundamental ability to compute, and that what makes human distinctive is social learning abilities, and that that's where a lot of our ability has gone, our ability to see other people, to empathize with other people, to copy other people, to incorporate bodies of information that are learned by other people.

And so I am not an expert in this topic, but it's a very appealing group of ideas that the adaptations that humans have are ones that allow us to access a rich amount of shared knowledge and not just to rely on figuring out each thing.

So that's not obviously the same as just add more computability, but maybe it has some similarities.

So the model that—this is really outside my expertise, but ideas that have been floated, and I will summarize them possibly badly, are that in every group of human beings of hundreds of people, which is the size of a band or sometimes a thousand of people, they accumulate shared cultural knowledge, shared—

knowledge about tools, knowledge about life strategies, and they build up a shared knowledge more and more and more and more.

But if you have a limited size group of people that's not interacting with the sufficiently large group of people, either occasionally this group has an information loss, there's a natural disaster, key elders in the group,

die and knowledge gets lost and there's not a critical mass of shared knowledge.

But once it goes above some kind of critical mass, the group can get larger, the amount of shared knowledge becomes greater, and then you have a runaway process where an increasing body of shared knowledge of how to make particular tools, how to innovate, patterns of innovation,

and so on, language, conceptual ideas run amok.

So an example that I've heard talked about in this context is what happened with, for example, indigenous Tasmanians.

You probably know this story, but

About 10,000 years ago, the ancestors of people in Tasmania, which is this large island south of Australia, were continuous with the aboriginal populations of Australia.

They had fire.

They lost it.

And they lost fire because it got forgotten somehow, and it's a cold place.

And they just forgot it.

The cultural knowledge lost it.

So what you actually have in the world is—50,000 years ago is tens or hundreds—

thousands or tens of thousands of different human groups, each of them possessing local knowledge, rarely exchanging with each other.