A quarter of the respondents said they expected the value of their homes to increase by at least 10% a year, significantly above the historical average. However, that also was the survey in which about four in 10 said they expected a bubble to burst in the next three years.
Shiller, who earned a national reputation by calling the 2000 tech stock bubble shortly before it burst, is hedging his bets.
He bought a second house on Long Island a few years ago, despite his view that a psychological frenzy was gripping housing that matched the earlier mania for tech stocks. The house is worth a lot more now. He's not selling but said, "I pulled back on my real estate portfolio a bit. I don't see any sense of immediate urgency."
Millions of people still have to change their thinking, Shiller said. "That's a gradual thing."
It's a human temptation to stay in the game until the last moment. But Duncan, the economist for the mortgage bankers, doesn't seem to feel it. Workmen are prepping his home now for a sale, he said.
Acting on his gut has served him well before. In 1988, as the economist was moving to Washington, he went to look at a house that was for sale. Three couples were already there. They started a bidding war in the living room.
"This is irrational behavior," Duncan remembers thinking. He decided to rent. Shortly afterward, the market crashed.
In 1993, he decided it was a good time to own. The price he paid for his house was about a third less than the previous owner, who had lost it in a foreclosure sale.
