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.

Critics of consumer capitalism like to think that consumers are manipulated and controlled by those who seek to sell them things, but for the most part it's the other way around: companies must make what consumers want and deliver it at the lowest possible price.

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

Speculators get a bad rap. In the popular imagination they're greedy, heedless, and amoral, adept at price manipulations and dirty tricks. In reality, they often play a key role in making markets run smoothly.

Being unemployed is even more disastrous for individuals than you'd expect. Aside from the obvious harm - poverty, difficulty paying off debts - it seems to directly affect people's health, particularly that of older workers.

Of course, politicians always say they're just describing their opponents' positions, even if they are in fact offering absurd caricatures, if not outright lies.

Publishers, naturally, loathe used books and have developed strategies to depress the secondhand market. They bring out new, even more expensive editions of popular textbooks every three to four years, in a classic cycle of planned obsolescence.