Bubbles and crashes are textbook examples of collective decision making gone wrong. In a bubble, all of the conditions that make groups intelligent - independence, diversity, private judgement-disappear.

I started in business journalism from the outside, so when I started writing about markets and business, I was struck by the fact that markets seemed to work well even though people are often irrational, lack good information and are not perfect in the way they think about decisions.

In the auto industry, there's one thing you can always count on: if a new environmental or safety rule is proposed, executives will prophesy disaster.

In industries where a lot of competitors are selling the same product - mangoes, gasoline, DVD players - price is the easiest way to distinguish yourself. The hope is that if you cut prices enough you can increase your market share, and even your profits. But this works only if your competitors won't, or can't, follow suit.

A consumer-finance agency is a good thing, but it would do well to teach consumers a simple lesson: if you don't understand the deal you're making, don't make it.

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.

Tough times have always lent themselves to nativist sentiments and closed-door policies. But in the case of highly skilled immigrants these policies are a recipe for stagnation.