1) The claimed growth of “pocket neighborhoods” (a handful of houses around a shared common yard) to reduce the necessary land for a house but still leave homeowners and children with a safe outdoor space to play in and entertain in. (See USA Today article.) This obviously could increase social interaction since there is far less private space. I haven’t seen any studies of this, but it would be hard to test, because families that move into pocket neighborhoods undoubtedly desire greater interaction than families moving into houses with private yards. So, even if there were more social capital in pocket neighborhoods, it is hard to disentangle how much is the shared yard and how much is the community-mindedness of the residents. [For more examples of pocket neighborhoods see Ross Chapin, Cottage Company, and this blog post.] A wikipedia article describes pocket neighborhoods in other areas like Boston (MA), Duluth (MN), Beloit (WI), Redmond (WA), among others. Pocket neighborhoods are somewhat related to other attempts to engineer more social capital through physical design, such as co-housing or New Urbanism.
2) Bob Putnam has written about the challenges of building social capital amidst greater diversity. One interesting approach to this challenge, is Singapore’s policy of rough ethnic quotas in public housing at the block and neighborhood level, begun in 1989, In theory this policy could be quite successful in building social cohesion and trust across the 3 major community groups in Singapore: the Malay (14%), the Indians (8%) and the Chinese (77%). Given the fact that 82-86% of the Singaporean population lives in public housing, the impact could be quite widespread. We’re not aware of good, careful studies of the social consequences of this mixing, and one should be wary of declaring victory based on the chastening US experience with HOPE VI. Mixed income housing under HUD’s HOPE VI program may be successful along some lines, but hasn’t led in general, in the studies we’re aware of (or see this report), to strong cross-class mixing in these neighborhoods. Read this Singapore Online Citizen piece for an update on Singapore’s Housing Integration (2/17/11).