http://onlinelibrary.wiley.com/doi/10.1111/j.1467-9477.2007.00176.x/abstract
If you are unfamiliar with Robert Putnam, here is a place to start.
His finding, which he himself suppressed for something like 10 years, is that the more diverse a neighborhood is, the less people interact, and the less they trust one another.
“Melting Pots” are schools for isolation.
All of our problems can be solved, but only if we tell the truth about them.