Yet the idea of a wealth effect doesn't stand up to economic data. The stock market boom in the late 1990s helped increase the wealth of Americans, but it didn't produce a significant change in consumption, according to David Backus, a professor of economics and finance at New York University. Before the stock market reversed itself, "you didn't see a big increase in consumption," says Backus. "And when it did reverse itself, you didn't see a big decrease."
Just another example of a popular notion that turns out to be wrong. Beware of simple explanations for complex topics.