But a massive new study, based on detailed interviews of nearly 30,000 people across America, has concluded just the opposite. Harvard political scientist Robert Putnam -- famous for "Bowling Alone," his 2000 book on declining civic engagement -- has found that the greater the diversity in a community, the fewer people v**e and the less they volunteer, the less they give to charity and work on community projects. In the most diverse communities, neighbors trust one another about half as much as they do in the most homogenous settings. The study, the largest ever on civic engagement in America, found that virtually all measures of civic health are lower in more diverse settings.

Putnam claims the US has experienced a pronounced decline in "social capital," a term he helped popularize. Social capital refers to the social networks -- whether friendships or religious congregations or neighborhood associations -- that he says are key indicators of civic well-being. When social capital is high, says Putnam, communities are better places to live. Neighborhoods are safer; people are healthier; and more citizens v**e.

The results of his new study come from a survey Putnam directed among residents in 41 US communities, including Boston. Residents were sorted into the four principal categories used by the US Census: black, white, Hispanic, and Asian. They were asked how much they trusted their neighbors and those of each racial category, and questioned about a long list of civic attitudes and practices, including their views on local government, their involvement in community projects, and their friendships. What emerged in more diverse communities was a bleak picture of civic desolation, affecting everything from political engagement to the state of social ties.

http://archive.boston.com/news/globe/ideas/articles/2007/08/05/the_downside_of_diversity/