Two criminals were put in prison and could not communicate with each other. If two people don't expose each other, everyone will go to jail for a year because of uncertain evidence; If one person exposes and one person is silent, the whistleblower will be released immediately because of meritorious service, and the silent person will be imprisoned for ten years because of non-cooperation; If they expose each other, they will be sentenced to eight years in prison because the evidence is conclusive.
Because prisoners can't trust each other, they tend to expose each other rather than keep silent together. Finally, Nash equilibrium only falls on the non-cooperative point.
Extended data:
Prisoner's dilemma is a representative example of non-zero-sum game in game theory, which reflects that the optimal choice of individuals is not the optimal choice of groups. In other words, in a group, individuals make rational choices, but it often leads to collective irrationality. Although the dilemma itself is only a model, similar situations will occur frequently in real price competition and environmental protection.
In his book The Evolution of Cooperation, Robert axelrod explored the extension of the classic prisoner's dilemma and called it "repeated prisoner's dilemma" (IPD).
The prisoner's dilemma game is the basis of some theories of human cooperation and trust. Assuming that the prisoner's dilemma can simulate the communication between two people who need trust, then the cooperative behavior of the group can be simulated by the variation of repeated games of multiple participants. This has aroused the lasting interest of many scholars.
In 1975, Grofman and Pool estimated that more than 2,000 academic articles were devoted to this research.
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