Prisoner's Dilemma

In a standard prisoner’s dilemma, each player does better by defecting whatever the other does, yet both would be better off if both cooperated. The puzzle concerns the structure of incentives, not a general claim that people are selfish. Individually rational choices can produce a collectively worse outcome.

The crucial feature is that defection looks preferable to each player regardless of what the other chooses. If the other cooperates, defecting obtains the benefit without contributing; if the other defects, cooperating only adds a personal cost. Yet mutual cooperation would leave both better off than mutual defection. This structure distinguishes the dilemma from simple mistrust, a coordination problem, or a conflict in which one player must lose for the other to gain.

Imagine two neighbors maintaining a shared garden. Each enjoys it even if only the other works, but neither enjoys it if both stop. List the benefits and effort costs for every combination of choices before deciding whether this really has the prisoner’s-dilemma structure.

Repeated interaction, observation, and credible commitments can change the game. They do not guarantee cooperation: mistakes, power differences, and an approaching final encounter matter. Moral reasons may also favor contribution independently of personal gain, so distinguish the strategic question of stability from the ethical question of what each owes.

In the garden example, a shared maintenance agreement can change incentives by making commitments observable. But enforcement itself raises ethical questions: who sets the workload, who excuses illness, and what happens to a resident unable to pay? A successful cooperation scheme needs a practical explanation of stability and a moral explanation of its terms. A rule can keep people contributing while still distributing burdens unfairly, so those two assessments should remain visible.