Glossary » prisoner’s dilemma

prisoner’s dilemma

a classic problem statement describing a situation where what is rational for an individual is in conflict with what is rational for the group (as with the commons problem). This type of problem is useful for describing problems in coordinating the use of groupware systems.

The Prisoner’s Dilemma goes like this: two criminals are arrested for a crime and placed in separate rooms. Each is given the opportunity to confess or remain silent. Each is told the following. If neither of you confess, then a minor penalty will apply to both of you. If you confess and the other prisoner does not, then you will be set free, and he will get a severe punishment. However, if both of you confess, then you will both be charged for the full crime, though some leniency will be shown because of your confession.

This challenge is typically represented in a table like the following. The problem is that individually, each prisoner reasons that it is more rational to confess regardless of what the other prisoner does. However, from the point of view of both of them, it would be most rational if neither confessed. Without the opportunity to coordinate their actions, they aren’t able to achieve the outcome that is best for the pair of them.