In 1907, Sir Francis Galton asked 787 villagers to guess the weight of an ox. None of them got the right answer, but when Galton averaged their guesses, he arrived at a near perfect estimate. This is a classic demonstration of the “wisdom of the crowds”, where groups of people pool their abilities to show collective intelligence. Galton’s story has been told and re-told, with endless variations on the theme. If you don’t have an ox handy, you can try it yourself with beans in a jar.

To Iain Couzin from Princeton University, these stories are a little boring. Everyone is trying to solve a problem, and they do it more accurately together than alone. Whoop-de-doo. By contrast, Couzin