Robin Dunbar

Hello, I'm Robin Dunbar.

I'm a professor of evolutionary psychology at the University of Oxford.

And I spent most of my life studying monkeys and humans and feral goats.

And I think the most surprising thing that I've seen really with monkeys is just how Machiavellian and scheming they can actually be.

They really are like watching humans.

Yeah, it's actually much easier to define friendships in monkeys because their friendships are very similar to our kind of friendships, the way they set them up.

I guess romantic relationships...

They kind of look the same, but I mean, it does vary enormously from species to species and even within a species.

Well, just like humans, I suppose.

Different individuals, you know, have different intensities of relationships.

There are introverts and extroverts.

It's complete chaos.

Actually, to be fair, a lot of the stuff that we've spent the last 20 years doing has been on humans in order to understand monkeys better.

LAUGHTER You can do things with humans that you can't do with monkeys.

You can stick humans in neuroimaging machines and stuff like that, and you can ask them questions.

OK, so...

The number of friends you can have is limited basically by the size of your brain.

That's a generic relationship across mammals as a whole, basically.

But in primates, it takes a very quantitative form.

What we were able to do with humans originally was to look at your personal social network and tie that to the size of different bits of your brain.