Prisoner's Dilemma?
I have the basic concept of the Prisoner's Dilemma, but I need to find more info and need to obtain a better understanding of the Iterated Prisoner's Dilemma (IPD), can anyone better explain IPD or link me to some sites that can help?
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Two men are arrested, but the police do not have enough information for a conviction. The police separate the two men, and offer both the same deal: if one testifies against his partner (defects/betrays), and the other remains silent (cooperates with/assists his partner), the betrayer goes free and the one that remains silent gets a one-year sentence. If both remain silent, both are sentenced to only one month in jail on a minor charge. If each 'rats out' the other, each receives a three-month sentence. Each prisoner must choose either to betray or remain silent; the decision of each is kept secret from his partner. What should they do? If it is assumed that each player is only concerned with lessening his own time in jail, the game becomes a non-zero sum game where the two players may either assist or betray the other. The sole concern of the prisoners seems to be increasing his own reward. The interesting symmetry of this problem is that the optimal decision for each is to betray the other, even though they would be better off if they both cooperated.
There is also an extended "iterative" version of the game, where the classic game is played over and over, and consequently, both prisoners continuously have an opportunity to penalize the other for previous decisions. If the number of times the game will be played is known, the finite aspect of the game means that (by backward induction) the two prisoners will betray each other repeatedly.