John Luik has some thoughts on the recent study by Robert Putnam of Harvard:

For at least the last twenty years the cultural and political elites of the United States have championed the cause of multiculturalism by claiming that diversity was something that made all of us better. Little effort was ever made to define precisely just what was meant by diversity, difference or most crucially "better." Nor was there any significant research that provided empirical support for the claim that multiculturalism and diversity translated into better people, better communities, better organizations and businesses or a better country.

But now a considerable amount of solid evidence about multiculturalism is in, and it suggests that far from something positive, it is a corroding and corrupting influence on just about everything that it comes in contact with, from social capital, trust, and community spirit to altruism, volunteering, friendship and even happiness.

That's the startling conclusion from Harvard's Robert Putnam best known as the author of Bowling Alone. According to Putnam a variety of research from the United States, Canada, Australia and Europe shows that ethnic diversity is associated with lower social trust, lower "investment in public goods," less reciprocity, and less willingness to contribute to the community. In workplace situations diversity is associated with "lower group cohesion, lower satisfaction and higher turnover."