Coruscation

The notion of housing as an investment first began to blossom after World War II, when the nesting urges of returning soldiers created a construction boom. Demand was stoked as their bumper crop of children grew up and bought places of their own. The inflation of the 1970s, which increased the value of hard assets, and liberal tax policies both helped make housing a good bet. So did the long decline in mortgage rates from the early 1980s.

Despite all these tailwinds, prices rose modestly for much of the period. Real home prices increased 1.1 percent a year after inflation, according to Mr. Shiller's research.

By the late 1990s, however, the rate was 4 percent a year. Happy homeowners were taking about $100 billion a year out of their houses, which paid for a lot of good times.

"The experience we had from the late 1970s to the late 1990s was an aberration," said Barry Ritholtz of the equity research firm Fusion IQ. "People shouldn't be holding their breath waiting for it to happen again."