Bowling together: sprawl and social virtue.

THE SPREAD-OUT, suburban, auto-centered way of life has been blamed for everything from anomie to obesity. The well-known sociologist Robert Putnam has even quantified his animus against sprawl, claiming that it decreases community involvement by 20 percent according to a variety of measures.

More recent research should take some of the heat off suburbia. The economists Jan K. Brueckner of the University of California at Irvine and Ann G. Largey of Dublin City University began a new study, published by Brueckner's employer, wondering if sprawl created "negative externalities"--that is, costs imposed on others. In particular, they wanted to know whether living in areas with low population densities reduced social interaction, something we might get less of when other people decide to live away from us. They found that interactions with neighbors, including invitations to visit, are actually higher in less dense areas.

The Brueckner/Largey study concerns personal social activity, not the "civic" concerns of critics like Putnam. But another paper, published last year by the Harvard Institute of Economic Research, found that measures of civic participation also "decline in dense communities and rise in the suburbs" and that "there is no evidence suggesting that discouraging medium-density, car-based living will improve social capital."

The authors, Harvard economists Edward L. Glaeser and Joshua D. Gottlieb, conclude that Putnam had it backward. Whatever caused the decline in social interaction, they say, has been somewhat offset by sprawl. Along those lines, they note that Putnam believed time spent commuting was injuring civic life. But contrary to his assumption, lower-density areas are associated with shorter commutes.