Working Memory and Community
[todo: just publishing old drafts, this one might be worth thinking for human geography]
Working memory is limited. To remind oneself of the community, one must experience it, often. For this reason, living physically close to the community increases physical visibility, which in turn increases physical interaction.
Repeat this and it may become habit.
[I think I was getting at how habit of physical interaction is somewhat required for socialization, maintaining a community]