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.

It amazes me how people are often more willing to act based on little or no data than to use data that is a challenge to assemble.

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

Can a controlled experiment explain why people like Kewpie dolls in one year, Beanie Babies in another, and American Girl dolls this year? Yet social scientists are asked to answer analogous questions. We economists and perhaps psychologists shouldn't overreact to the derision. That is, we shouldn't try to overlay a false sense of precision on our admittedly squooshy work.

In the longer run and for wide-reaching issues, more creative solutions tend to come from imaginative interdisciplinary collaboration.

Stock prices are likely to be among the prices that are relatively vulnerable to purely social movements because there is no accepted theory by which to understand the worth of stocks....investors have no model or at best a very incomplete model of behavior of prices, dividend, or earnings, of speculative assets.

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.