| Tit-for-tat |
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Information AboutTit-for-tat |
| CATEGORIES ABOUT TIT FOR TAT | |
| non-cooperative games | |
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OVERVIEW This strategy is dependent on four conditions that has allowed it to become the most prevalent strategy for the Prisoner's Dilemma: # Unless provoked, the agent will always cooperate # If provoked, the agent will retaliate # The agent is quick to forgive # The agent must have a good chance of competing against the opponent more than once. In the last condition, the definition of "good chance" depends on the Payoff Matrix of the prisoner's dilemma. The important thing is that the competition continues long enough for repeated punishment and forgiveness to generate a long-term payoff higher than the possible loss from cooperating initially. A fifth condition applies to make the competition meaningful: if an agent knows that the next play will be the last, it should naturally defect for a higher score. Similarly if it knows that the next two plays will be the last, it should defect twice, and so on. Therefore the number of competitions must not be known in advance to the agents. Against a variety of alternative strategies, tit for tat was the most effective, winning in several annual automated tournaments against (generally far more complex) strategies created by teams of computer scientists, economists, and psychologists. Game theorists informally believed the strategy to be optimal (although no proof was presented). It is important to know that tit for tat still is the most effective strategy if you compare the average performance of each competing team. The team which recently won over a pure tit for tat team only outperformed it with some of their algorithms because they submitted multiple algorithms which would recognize each other and assume a master and slave relationship (one algorithm would "sacrifice" itself and obtain a very poor result in order for the other algorithm to be able to outperform Tit for Tat on an individual basis, but not as a pair or group). Still, this "group" victory illustrates an important limitation of the Prisoner's Dilemma in representing social reality, namely, that it does not include any natural equivalent for friendship or alliances. The advantage of "tit for tat" thus pertains only to a Hobbesian world of rational solutions, not to a world in which humans are inherently social. EXAMPLE OF PLAY
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| When The Variables Face Off Against Each Other, Each Refrains From Giving Evidence In All 6 Games 6 3 | 18 points, the final score being Variable(1) - 18 Variable(2) - 18 |
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| When The Defectors Face Off, Each Gives Evidence Against The Other In All 6 Games 6 1 | 6 points, the final score being Defector(1) - 6 Defector(2) - 6 |
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