In the short run and for decisions unlikely to have broad impact, it may be more cost effective to use just one expert.

The good news is that, at least in economics, I've seen movement away from its overemphasis on mathematical models of purely rational behavior to a more eclectic and commonsense approach: research that is, among other things, more respectful of insights from psychology.

My father, Benjamin Shiller, told me not to believe in authorities or celebrities - that society tends to imagine them as superhuman. It's good advice. People are snowed by celebrities all the time. In academia people have this idea of achieving stardom - publishing in the best journals, being at the best university, writing on the hot topic everyone else is writing about. But that's what my father told me not to do. He taught me that you have to pursue things that sound right to you.

Economists who adhere to rational-expectations models of the world will never admit it, but a lot of what happens in markets is driven by pure stupidity - or, rather, inattention, misinformation about fundamentals, and an exaggerated focus on currently circulating stories.

Marketers know that if people you respect - perhaps laughably including entertainers and athletes - say they like a product, you're more likely to buy.

Somehow, talking to young students brings you back to reality - it should, anyway.

News media stimulate bubbles, since stories about them boost their audience.