Cooperation only happens when you iterate every time in a one-on-one fashion with the same players over and over again. For example: the relationship with your

Cooperation only happens when you iterate every time in a one-on-one fashion with the same players over and over again. For example: the relationship with your local grocer, who has a reputation to build. But it is the wrong metaphor for most real issues in social policy. Pollution is a tragedy of the commons problem.