Prisoner's Dilemma

The prisoner's dilemma is a standard example in game theory of a game in which two rational participants, each acting in their own individual self interest, do not produce the outcome that would be best for the two of them jointly. In its classic formulation, two members of a criminal gang are held separately and each is offered a lighter sentence for betraying the other; if both stay silent both receive a light sentence, if both betray each other both receive a moderate sentence, but if only one betrays the other the betrayer goes free while the other receives the harshest sentence, so that betrayal is the individually rational choice for each prisoner regardless of what the other does, even though mutual silence would have produced a better outcome for both. The game was framed in its familiar prisoner narrative by Albert Tucker in 1950 based on earlier work at the RAND Corporation by Merrill Flood and Melvin Dresher, and it has since become a central model for studying cooperation and conflict in economics, evolutionary biology and political science, particularly in its iterated form, in which the same two players face the dilemma repeatedly.