Unlike many species, humans have had to adapt to living in large crowds. Yet in many ways, our crowds are as predictable as animals’.

Question: What are the similarities and differences between animal and human crowds?

Iain Couzin: Well, in many of the animal groups that we're looking at, you know, I mentioned ants, and they're a sort of special genetic sort of closeness, so we can exclude them for now. But even when we look at selfish organisms like the fish, you know, they're all locusts, you know, they've evolved to live within incredibly large groups and incredibly large societies. Now, we humans haven't. You know, we're thrown into these large cities now, but that's not actually how we evolved. And so we don't have sort of specific rules to optimize our situation here. And furthermore, you know, our mode of communication, verbal communication and written communication, is relatively slow compared to the sort of the mass media and all of the information that we have now. So there's some sort of fascinating challenges from a biological perspective to our societies.

But what we do find is that people are good at learning how to behave in crowds. For example, if you were to take people from, I don't know, the center of America, who have never been to a large city and pop them in the middle of Manhattan, not only would this be a sort of cultural shock, it would actually be difficult for them to behave within these crowds. These are sort of learnt behaviors that you sort of try things out and you eventually kind of optimize how to behave within these environments.

And then we film and we track people within crowds, what sort of astonishes me is how predictable, from a statistical perspective, how predictable crowds are. And so each individual, we can't necessarily predict, you know, whether you're going to go left or right, but when we start getting large groups of individuals, we can predict properties like how many lanes will form or, you know, what are certain times of day who will generally tend to move where. And we can also make predictions about congestion in these environments, and so forth.

Recorded on December 15, 2009
Interviewed by Austin Allen