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.

Until the nineteen-seventies, Western countries paid little attention to corruption overseas, and bribery was seen as an unpleasant but necessary part of doing business there. In some European countries, businesses were even allowed to deduct bribes as an expense.

The U.S. is excellent at importing cheap products from the rest of the world. Let's try importing some human capital instead.

Campaigns fail if they waste resources courting voters who are unpersuadable or already persuaded. Their most urgent task is to find and persuade the few voters who are genuinely undecided and the larger number who are favorably disposed but need a push to actually vote.

Of course, looking tough on inflation is part of any central banker's job description: if investors believe that inflation is going to get out of control, you end up with higher interest rates and capital flight, and a vicious circle quickly ensues.

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.

The smartest groups, then, are made up of people with diverse perspectives who are able to stay independent of each other.