The Prisoner's Dilemma game was first proposed by Merrill Flood in 1951. It was formalized and defined by Albert W. Tucker. The name refers to the following hypothetical situation:
Two criminals are captured by the police. The police suspect that they are responsible for a murder, but do not have enough evidence to prove it in court, though they are able to convict them of a lesser charge (carrying a concealed weapon, for example). The prisoners are put in separate cells with no way to communicate with one another and each is offered to confess.
If neither prisoner confesses, both will be convicted of the lesser offense and sentenced to a year in prison. If both confess to murder, both will be sentenced to 5 years. If, however, one prisoner confesses while the other does not, then the prisoner who confessed will be granted immunity while the prisoner who did not confess will go to jail for 20 years.
What should each prisoner do?