Businesses that have gone through an episode of hyperinflation become understandably alert to the threat of it: at the first hint of inflation, they're likely to increase prices, since they've learned that if they don't, and inflation hits, their businesses will be wrecked.

Popular as Keynesian fiscal policy may be, many economists are skeptical that it works. They argue that fine-tuning the economy is a virtually impossible task, and that fiscal-stimulus programs are usually too small, and arrive too late, to make a difference.

Behavioral economists have shown that a sizable percentage of people are willing to pay real money to punish people who are taking from a common pot but not contributing to it. Just to insure that shirkers get what they deserve, we are prepared to make ourselves poorer.

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

Pop music thrives on repetition. You know a song's a hit when you've heard it so often that you'll be happy never to hear it again.

Academics, who work for long periods in a self-directed fashion, may be especially prone to putting things off: surveys suggest that the vast majority of college students procrastinate, and articles in the literature of procrastination often allude to the author's own problems with finishing the piece.

Intellectual-property rules are clearly necessary to spur innovation: if every invention could be stolen, or every new drug immediately copied, few people would invest in innovation. But too much protection can strangle competition and can limit what economists call 'incremental innovation' - innovations that build, in some way, on others.