A lot of this is covered in the excellent book "The Cheating Culture", which I recommend. "Bowling Alone", as the article mentions, covers the "stay home and do your own thing" part of it, but the economic system we've set up, I believe, is far a far stronger influence. We've set up a system that's dog-eat-dog, every man for himself, "everything that happens to you is your own fault", "lift yourself up by your bootstraps" and approaching hypercompetition. When it feels like you're one medical emergency, job loss, or bad debt away from homelessness, and have only pathetic (and painted as only for life's losers) safety nets there for you, you're out of necessity going to have to trust less. Add in the fact that many areas in this country have to deal with the daily threat of violence, and you get a toxic brew of distrust.

This is sad for more than sentimental reasons, as the article mentions. The "Economics of Trust" is important for easy dealmaking, credit, and other things. More here:

http://trustedadvisor.com/trustmatters/software-programming-...