Diversity does not produce “bad race relations,” Putnam says. Rather, people in diverse communities tend “to withdraw even from close friends, to expect the worst from their community and its leaders, to volunteer less, give less to charity and work on community projects less often, to register to vote less, to agitate for social reform more, but have less faith that they can actually make a difference, and to huddle unhappily in front of the television.” Putnam adds a crushing footnote: his findings “may underestimate the real effect of diversity on social withdrawal.”
Neither age nor disparities of wealth explain this result. “Americans raised in the 1970s,” he writes, “seem fully as unnerved by diversity as those raised in the 1920s.” And the “hunkering down” occurred no matter whether the communities were relatively egalitarian or showed great differences in personal income. Even when communities are equally poor or rich, equally safe or crime-ridden, diversity correlates with less trust of neighbors, lower confidence in local politicians and news media, less charitable giving and volunteering, fewer close friends, and less happiness.
Putnam does say that these harms are across the short and mid-term, and in the long-run diversity remains an overall benefit. Still, these are findings to give one pause.
I first came across the study at MvdG's place (this is an expansion of the comment I left there), and have seen it in several other locales since then. As I blog rather frequently on the perks of diversity, and consider myself a cheerleader for its benefits, I feel it's only fair to blog on this study as well.
The Putnam study is indeed distressing. The one variable I didn’t see him control for (and he may have, I'm relying on a summary) was comparing people who grew up in diverse surroundings versus those who moved in at adulthood. Most of the research I’ve seen as indicated that childhood is a crucial time for getting people to accept and thrive in diverse environments–and that they experience performance leaps as a result. Putnam’s study might indicate that these benefits don’t accrue if you start too late (this is also buttressed by his findings of long-term gains to offset the short- and mid-term losses). If Putnam's study is to be synthesized with the studies that do find long-term benefits for children who grow up and are educated in diverse environments, it would suggest that integrating schools is a "try-or-die" situation--if you don't catch kids early enough, simply putting them in diverse situations later on will blow up in your face.
That being said, Putnam's study does impress that diversity is not a panacea. It has benefits, especially along the axis of racial distributional justice. But its pursuit can have costs as well, and it is unfair not to take those costs into account. Ultimately, I think the best use of our brightest minds, confronting Putnam's work, is to figure out how to eliminate the relationship he's finding. More than the study itself, I am worried by the people reacting to it with satisfaction bordering on glee. Regardless of what you think about various state-incentivized plans to encourage diverse living, everybody is hurt when simply living next door to someone of another culture risks lowering your quality of life--not because of increased crime or worse schools, but because of psychological discomfort and distress. Putnam's study doesn't just describe a finding, it describes a problem.
It's a problem--but I don't believe that it is an immutable one. People can grow comfortable around those who previously thought to be inscrutably, exotically different. It's a problem, but one that we can solve. So, let's solve it.