WASHINGTON - The wanderlust that helped define the American character has been reined in by the recession and the collapse in housing prices, according to a study showing fewer Americans changing residences than at any time since World War II.

About 12 percent of Americans moved in each of the last two years, down from 13 to 14 percent a year during the first part of this decade. Historical trends show a more precipitous drop. In any given year throughout the 1990s, 16 to 17 percent of Americans changed homes. In the 1950s and 1960s, it was one in five.

William Frey, a Brookings Institution demographer who wrote the study, said the economic slowdown has accelerated a long-term trend of people growing more rooted as homeownership has risen and society has gotten older with the aging of the baby boomers. Add the bursting of the housing bubble, the credit crisis, and the resulting recession, and many people are cemented in place.

"This triple whammy of forces made it riskier for would-be homebuyers to find financing, would-be sellers to receive good value for their home, and potential long-distance movers to find employment in areas where jobs were previously plentiful," said Frey, who analyzed statistics from the Census Bureau and the IRS for the recent study.

Frey paints a picture of an America settling into stasis. Philadelphia and other metropolises such as New York, Boston, Chicago, and Los Angeles - those that had been losing tens of thousands of residents in search of more affordable housing - held on to more people.

The phenomenon affected people across all demographics.

The young and the footlose in their 20s are usually responsible for an outsize share of those who move, and they showed the steepest decline as jobs grew scarce, prompting many to return to their parents' homes.

Even unemployed people are less mobile.

"Five years ago, they might have decided to go to Las Vegas or Orlando, whether they had a job or not, because they thought they could find something," said Frey. "Now they're stuck."

Frey said he expected people to start relocating again once the economy improves, though not to the levels of half a century ago.

"We're a country of pioneers," he said. "People moved here in the early days of the formation of the country. They were always moving, westward or suburb-ward or to the Sunbelt.

"The idea that we can improve our lot in life by migration, not by standing where we are and hoping it will get better, is in our genes."