In a study bound to have a huge impact on debates over such topics as immigration policy and affirmative action in employment and education, Harvard political scientist Robert Putnam has reportedly found 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.” ...
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.”
