Neaty, seany. Mostly familiar but a nice little well-organized statement.

w/r/t the "tit-for-tat" system: In my org. theory class, we recently discussed strong and weak social bonds. Strong social bonds are those that arise from 'tit-for-tat' strategies. THey're more common in fraternities and sororities, in groups like the Mafia and the Masons, and geographically, in the American South. Strong social bonds come about when you do favors for one another to create a strong sense of obligation and when you generate knowledge about other people which you can then hang over their heads. Weak social bonds are lighter exchanges of services and information that are more common in cultures and subcultures of greater reserve. Where there are weak social bonds there tend to be more of them (because there is less fear around loyalty issues) and thus, paradoxically, a stronger community with a more reinforced social network, because the voluntary association of two individuals is the primary social unit. Because the bonds are lighter, they can be changed and broken without acrimony or fear of revenge.

The strong-bond communities have more involuntary associations in social groupings. For that reason these communities have can be broken down by destroying a few nodes or taking out a central person or ritual that generates political power.

I've always had trouble with the premise of the prisoner's dilemma: "it doesn't matter whether you or your friend did it or not." To me, that matters a whole lot - I have a lot of trouble entertaining the question as abstract. It's hard to imagine doing anything buy pleading innocent if I am innocent.