"why we routinely trust non-kin (an evolutionary puzzle, to be sure), how the majority of us are honest, and that a minority of us are dishonest. That dishonest minority are the free riders of societal systems, and security is how we protect society from them. I will model the fundamental trade-off of societal security -- individual self-interest vs. societal group interest -- as a group prisoner's dilemma problem, and use that metaphor to examine the basic mechanics of societal security."

Some of these ideas remind me of a book I read recently: "The Selfish Gene". In it, Richard Dawkins approaches these same questions from the gene standpoint, and uses game theory to explain how good / bad behavior evolves in an ecosystem, and why free-riding is not always the evolutionarily stable strategy.

http://en.wikipedia.org/wiki/Evolutionarily_stable_strategy