What the investment community does like is short-term measures designed to boost share prices.

This intelligence, or what I'll call "the wisdom of crowds," is at work in the world in many different guises. It's the reason the Internet search engine Google can scan a billion Web pages and find the one page that has the exact piece of information you were looking for. It's the reason it's so hard to make money betting on NFL games, and it helps explain why, for the past fifteen years, a few hundred amateur traders in the middle of Iowa have done a better job of predicting election results than Gallup polls have.

In conditions of uncertainty, humans, like other animals, herd together for protection.

Companies have long gathered data to break down their customer base into specific segments. Now political parties have become adept at micro-targeting, too, using data on shopping habits, leisure activities, voting histories, charity donations, and so on, in order to pinpoint likely supporters and the type of appeal most likely to win them over.

The fact that cognitive diversity matters does not mean that if you assemble a group of diverse but thoroughly uninformed people, their collective wisdom will be smarter than an expert's. But if you can assemble a diverse group of people who possess varying degrees of knowledge and insight, you're better off entrusting it with major decisions rather than leaving them in the hands of one or two people, no matter how smart those people are.

I do think that procrastination evolved in humans for good reasons. If you're trying to stay alive as a human being on the savanna 20,000 years ago, worrying about what's right behind that bush is a lot more important than worrying about what might happen three weeks from now.

The important thing about groupthink is that it works not so much by censoring dissent as by making dissent seem somehow improbable.