5 - Prisoners Dilemma

A prisoner’s dilemma is a paradoxical situation in which individuals appearing to choose for their self-interest, will not have an optimal outcome as a group. In a classic prisoner’s dilemma, individuals have the greatest payoffs if they betray the group instead of cooperating with the others. While choosing self-interest is incentivized, in repeating the game, players can devise a strategy that would actually rewards cooperation.

In the classic prisoner’s dilemma two bank robbers, arrested and interrogated in separate rooms, have a choice to cooperate (not betray each other by remaining silent) or to defect (betray the other by testifying). The authorities can only prove the case if they can convince at least one of them to betray the other and testify. Both robbers can minimize total jail time by cooperating and remaining silent, but they are better off individually if they defect (i.e. betray the other). The best-case scenario in terms of shorter jail time for both is when they both cooperate and remain silent.

In society, this is often shown as the “tragedy of the commons”, where it is in the collective interest not to deplete collective natural resources (e.g., a grassland for grazing), but it appears to be in the individual interest to take “as much as possible” from the collective resources. In society, people are often taught to take the best interest of society in mind, and there are often incentives in place to do so. Also, people reciprocate behavior, and for instance reward kindness and collaboration.