John Leo. “Bowling With Our Own Robert Putnam’s sobering new diversity research scares its author.” City Journal. June 25th, 2007 – “Harvard political scientist Robert Putnam, author of Bowling Alone, is very nervous about releasing his new research, and understandably so. His five-year study shows that immigration and ethnic diversity have a devastating short- and medium-term influence on the social capital, fabric of associations, trust, and neighborliness that create and sustain communities. He fears that his work on the surprisingly negative effects of diversity will become part of the immigration debate, even though he finds that in the long run, people do forge new communities and new ties.
Putnam’s study reveals that immigration and diversity not only reduce social capital between ethnic groups, but also within the groups themselves. Trust, even for members of one’s own race, is lower, altruism and community cooperation rarer, friendships fewer. The problem isn’t ethnic conflict or troubled racial relations, but withdrawal and isolation. Putnam writes: ‘In colloquial language, people living in ethnically diverse settings appear to ‘hunker down’—that is, to pull in like a turtle.'”