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.

A major boom in real stock prices in the US after Black Tuesday brought them halfway back to 1929 levels by 1930. This was followed by a second crash, another boom from 1932 to 1937, and a third crash. Speculative bubbles do not end like a short story, novel, or play. There is no final denouement that brings all the strands of a narrative into an impressive final conclusion. In the real world, we never know when the story is over.

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.

Physicists have a bias to aspire to be "seers" like Einstein rather than "craftspeople" who do simple and practical research. I have seen that in economics departments. The same must be true to some extent in other departments.

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.

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

Life's meaning heavily benefits from lifelong bonds.