The smartest groups, then, are made up of people with diverse perspectives who are able to stay independent of each other. Independence doesn't imply rationality or impartiality, though. You can be biased and irrational, but as long as you're independent, you won't make the group any dumber.

You can't fuel real economic growth with indiscriminate credit. You can only fuel it with well-allocated, long-term investment.

If army ants are wandering around and they get lost, they start to follow a simple rule:Just do what the ant in front of you does. The ants eventually end up in a circle. There's this famous example of one that was 1,200 feet long and lasted for two days; the ants just kept marching around and around in a circle until they died.

The Internet has become a remarkable fount of economic and social innovation largely because it's been an archetypal level playing field, on which even sites with little or no money behind them - blogs, say, or Wikipedia - can become influential.

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

On the simplest level, telecommuting makes it harder for people to have the kinds of informal interactions that are crucial to the way knowledge moves through an organization. The role that hallway chat plays in driving new ideas has become a cliche of business writing, but that doesn't make it less true.

The financial crisis of 2008 was not caused by investment banks betting against the housing market in 2007. It was caused by the fact that too few investors - including all of the big investment banks - bet too heavily on the housing market in the years before 2007.