A few weeks ago, I thought I’d do a demonstration of the wisdom of crowds. I was at a bat mitzvah reception and, as a game, the hosts asked each table to guess the number of Skittles in a big Tupperware bowl. I got everyone at our table to write down a guess and then averaged the results. Based on what social scientists have been saying, our collective answer should have been spot-on. Each of us had a vague hunch about how to pack small objects into big boxes, subject to much uncertainty. Taken together, though, our scraps of erudition should have accumulated while the individual errors cancelled out. But my experiment was an abject failure. Our estimate was off by a factor of two. Another table won the cool blinking necklace.
Wisdom of crowds is an old concept. It goes back to Ancient Greek and, later, Enlightenment thinkers who argued that democracy is not just a nice idea, but a mathematically proven way to make good decisions. Even a citizenry of knaves collectively outperforms the shrewdest monarch, according to this proposition. What the knaves lack in personal knowledge, they make up for in diversity. In the 1990s, crowd wisdom became a pop-culture obsession, providing a rationale for wikis, crowdsourcing, prediction markets and popularity-based search algorithms.