Narrator: This is Science Today. There's a tendency to regard today's society as being more on the move and less rooted, geographically, than our great-grandparents were. But historical records indicate the opposite. Claude Fischer, a sociologist at the University of California, Berkeley, says the major reason people moved in the past was because of financial constraints.

Fischer: Farm failed or there were too many people trying to live off the same farm or factory closed down or somebody got flooded out - or people just had economic hard times. They would move from place to place - whether it's from Europe to the United States or within the United States.

Narrator: But Fischer says a lot of those economic pressures have eased as we've become a more affluent and mobile society.

Fischer: Back in the 19th Century, when commuting meant walking basically, if your new job was more than two miles away, you probably would move. Today somebody can change jobs, fifty miles may not make a difference one way or the other, so it's easier to go from job to job today if you stay in the same metropolitan area and stay in the same neighborhood.

Narrator: For Science Today, I'm Larissa Branin.