Narrator: This is Science Today. You've heard that the gap between rich and poor is getting wider -- and Michael Hout can tell you why. Hout, a sociologist at the University of California, Berkeley, was on a team of sociologists who found that since the 1970s, several traditional means of spreading the wealth have disappeared.

Hout: In particular, what's been going on is corporations in response to overseas competition and other sorts of things have begun to move. First they move to other communities within the United States, now they've moved outside the United States. The tie between the corporation and its local community is completely ruptured now.

Narrator: Labor unions have lost strength too.

Hout: They used to be representing over 30 percent of American workers, they now represent only 11 percent of the private sector.

Narrator: Meanwhile, executive salaries have risen -- to an average of 225 dollars for every dollar the average worker makes.

Hout: Compare that to Germany where it's in the 20s, Japan where the CEO of a big Japanese firm will make 16 dollars for every dollar that his employees make -- it's an unbelievable difference.

Narrator: For Science Today, I'm Steve Tokar.