"We found that interaction goes down as population density goes up. So, turning it around, it says that interaction is higher where densities are lower," says Jan Brueckner, an economics professor at UC Irvine who led the study. "What that means is suburban living promotes more interaction than living in the central city."
Makes sense to me. When I lived in apartments, I never met anyone. People, people everywhere, but not a familiar face to greet. Now that I live in a house, I know my whole neighborhood. (And they know me - I'm the eccentric who wears shorts and flip-flops in the winter).
P.S. I've long thought that most foreign tourists to the U.S. get a deeply misleading picture of American life because they mostly visit big cities like NYC. To see the clean, convenient, spacious life most Americans enjoy, you've got to leave the cities and explore suburbia.