Sometimes 1,000 Heads Aren’t Better Than One

We are in the midst of an explosion of interest in collective intelligence, sometimes described as “the wisdom of crowds.” The basic idea is that if you aggregate the knowledge of a lot of people, you are likely to come up with the correct answer. If two heads are better than one, then a hundred heads are even better, and once we are dealing with thousands, a good answer starts to look inevitable. This idea has major implications for business decisions, stock markets, political movements and democracy itself.

In 1907, Francis Galton provided a memorable example. He asked about 800 people to guess the weight of an ox. None of them gave the correct answer (1,198 pounds), but the mean response was eerily accurate (1,197 pounds). Many experiments have replicated Galton’s finding, showing that if a large group is asked to make some numerical estimate, the mean answer (and sometimes the average) is remarkably good.