更改

The '''prisoner's dilemma''' is a standard example of a game analyzed in [[game theory]] that shows why two completely [[Rationality#Economics|rational]] individuals might not cooperate, even if it appears that it is in their best interests to do so. It was originally framed by [[Merrill Flood]] and [[Melvin Dresher]] while working at [[RAND Corporation|RAND]] in 1950. [[Albert W. Tucker]] formalized the game with prison sentence rewards and named it "prisoner's dilemma",<ref>Poundstone, 1992</ref> presenting it as follows:

The '''prisoner's dilemma''' is a standard example of a game analyzed in [[game theory]] that shows why two completely [[Rationality#Economics|rational]] individuals might not cooperate, even if it appears that it is in their best interests to do so. It was originally framed by [[Merrill Flood]] and [[Melvin Dresher]] while working at [[RAND Corporation|RAND]] in 1950. [[Albert W. Tucker]] formalized the game with prison sentence rewards and named it "prisoner's dilemma",<ref>Poundstone, 1992</ref> presenting it as follows:

The prisoner's dilemma is a standard example of a game analyzed in game theory that shows why two completely rational individuals might not cooperate, even if it appears that it is in their best interests to do so. It was originally framed by Merrill Flood and Melvin Dresher while working at RAND in 1950. Albert W. Tucker formalized the game with prison sentence rewards and named it "prisoner's dilemma", presenting it as follows:

The prisoner's dilemma is a standard example of a game analyzed in game theory that shows why two completely rational individuals might not cooperate, even if it appears that it is in their best interests to do so. It was originally framed by Merrill Flood and Melvin Dresher while working at RAND in 1950. Albert W. Tucker formalized the game with prison sentence rewards and named it "prisoner's dilemma", prensenting it as follows:

囚徒困境是博弈论分析的一个标准例子，它揭示了为什么两个完全理性的个体可能不会合作，即使这样做似乎对他们最有利。它最初是由 Merrill Flood 和 Melvin Dresher 于1950年在兰德公司工作时构建的。塔克将这个游戏正式化为监狱判决奖励，并将其命名为“囚徒困境” ，提出如下观点:

囚徒困境是博弈论分析的一个代表性例子，它揭示了为什么两个完全理性的个体可能不会合作，即使这样做似乎对他们最有利。它最初是由 Merrill Flood 和 Melvin Dresher 于1950年在兰德公司工作时构建的。Albert W. Tucker将这种博弈以囚徒的方式加以阐述，并将其命名为“囚徒困境” ，具体阐述如下：

{{quote|Two members of a criminal gang are arrested and imprisoned. Each prisoner is in solitary confinement with no means of communicating with the other. The prosecutors lack sufficient evidence to convict the pair on the principal charge, but they have enough to convict both on a lesser charge. Simultaneously, the prosecutors offer each prisoner a bargain. Each prisoner is given the opportunity either to betray the other by testifying that the other committed the crime, or to cooperate with the other by remaining silent. The possible outcomes are:

{{quote|Two members of a criminal gang are arrested and imprisoned. Each prisoner is in solitary confinement with no means of communicating with the other. The prosecutors lack sufficient evidence to convict the pair on the principal charge, but they have enough to convict both on a lesser charge. Simultaneously, the prosecutors offer each prisoner a bargain. Each prisoner is given the opportunity either to betray the other by testifying that the other committed the crime, or to cooperate with the other by remaining silent. The possible outcomes are:

{{引号 | 一个犯罪团伙的两名成员被捕入狱。每个囚犯都被关在禁闭室里，没有任何与其他囚犯沟通的方式。检察官缺乏足够的证据来定罪这两人的主要指控，但他们有足够的证据来定罪两个较轻的指控。同时，检察官向每个犯人提供了一个交易。每个囚犯都有机会出卖对方，作证说对方犯了罪，或者与对方合作，保持沉默。可能的结果是:

{{引号 | 一个犯罪团伙的两名成员被捕入狱。每个囚犯都被关在各自的禁闭室里，没有任何与其他囚犯沟通的方式。检察官缺乏足够的证据来定罪这两人的主要指控，但有足够的证据来定罪两人较轻的指控。同时，检察官向每个犯人提供了一个交易。每个囚犯都有机会出卖对方，证明对方犯下罪行，或者他们可以进行合作，保持沉默。可能的结果是:

* If A and B each betray the other, each of them serves two years in prison

* If A and B each betray the other, each of them serves two years in prison

 

* If A betrays B but B remains silent, A will be set free and B will serve three years in prison

* If A betrays B but B remains silent, A will be set free and B will serve three years in prison

 

* If A remains silent but B betrays A, A will serve three years in prison and B will be set free

* If A remains silent but B betrays A, A will serve three years in prison and B will be set free

 

* If A and B both remain silent, both of them will serve only one year in prison (on the lesser charge).}}

* If A and B both remain silent, both of them will serve only one year in prison (on the lesser charge).}}

 

 

It is implied that the prisoners will have no opportunity to reward or punish their partner other than the prison sentences they get and that their decision will not affect their reputation in the future. Because betraying a partner offers a greater reward than cooperating with them, all purely rational self-interested prisoners will betray the other, meaning the only possible outcome for two purely rational prisoners is for them to betray each other.<ref>{{cite web|last=Milovsky|first=Nicholas|title=The Basics of Game Theory and Associated Games|url=https://issuu.com/johnsonnick895/docs/game_theory_paper|accessdate=11 February 2014}}</ref>  In reality, humans display a [[systemic bias]] towards cooperative behavior in this and similar games despite what is predicted by simple models of "rational" self-interested action.<ref name = Fehr>{{cite journal | last1=Fehr | first1= Ernst | last2=Fischbacher | first2=Urs  | date= Oct 23, 2003 | title=The Nature of human altruism |journal=Nature | volume=425 | pages=785–91 | doi=10.1038/nature02043 | url=http://www.iwp.jku.at/born/mpwfst/04/nature02043_f_born.pdf | accessdate=February 27, 2013 | pmid=14574401 | issue=6960|bibcode = 2003Natur.425..785F }}</ref><ref name = Amos>{{cite book | title=Preference, belief, and similarity: selected writings. | publisher=Massachusetts Institute of Technology Press | first1= Amos | last1=Tversky | first2=Eldar | last2=Shafir | url=http://cseweb.ucsd.edu/~gary/PAPER-SUGGESTIONS/Preference,%20Belief,%20and%20Similarity%20Selected%20Writings%20(Bradford%20Books).pdf  | year=2004 | isbn=9780262700931 | accessdate=February 27, 2013}}</ref><ref name="Ahn">{{cite journal |last1 = Toh-Kyeong|first1 = Ahn|last2 = Ostrom|first2 = Elinor|last3 = Walker|first3 = James|date = Sep 5, 2002|title = Incorporating Motivational Heterogeneity into Game-Theoretic Models of Collective Action|journal = Public Choice|volume = 117|issue = 3–4|pages = 295–314|doi =10.1023/b:puch.0000003739.54365.fd |url = http://www.indiana.edu/~workshop/seminars/papers/ahnostromwalker_092402.pdf|accessdate = June 27, 2015|hdl = 10535/4697}}</ref><ref name="Hessel">{{cite journal|last1 = Oosterbeek|first1 = Hessel|last2 = Sloof|first2 = Randolph|last3 = Van de Kuilen|first3 = Gus|date = Dec 3, 2003|title = Cultural Differences in Ultimatum Game Experiments: Evidence from a Meta-Analysis|journal = Experimental Economics|volume = 7|issue = 2|pages = 171–88|doi = 10.1023/B:EXEC.0000026978.14316.74|url = http://www.econ.nagoya-cu.ac.jp/~yhamagu/ultimatum.pdf|accessdate = February 27, 2013|url-status = dead|archiveurl = https://web.archive.org/web/20130512175243/http://www.econ.nagoya-cu.ac.jp/~yhamagu/ultimatum.pdf|archivedate = May 12, 2013}}</ref> This bias towards cooperation has been known since the test was first conducted at RAND; the secretaries involved trusted each other and worked together for the best common outcome.<ref>{{Cite book | url=https://books.google.com/?id=WIhZlB86nJwC&pg=PT96&lpg=PT96&dq=rand+secretaries+prisoner%27s+dilemma#v=onepage |title = Why Most Things Fail|isbn = 9780571266142|last1 = Ormerod|first1 = Paul|date = 2010-12-22}}</ref> The prisoner's dilemma became the focus of extensive experimental research.<ref>Deutsch, M. (1958). Trust and suspicion. Journal of Conflict Resolution, 2(4), 265–279. https://doi.org/10.1177/002200275800200401</ref> <ref>Rapoport, A., & Chammah, A. M. (1965). Prisoner’s Dilemma: A study of conflict and cooperation. Ann Arbor, MI: University of Michigan Press.</ref>

It is implied that the prisoners will have no opportunity to reward or punish their partner other than the prison sentences they get and that their decision will not affect their reputation in the future. Because betraying a partner offers a greater reward than cooperating with them, all purely rational self-interested prisoners will betray the other, meaning the only possible outcome for two purely rational prisoners is for them to betray each other.<ref>{{cite web|last=Milovsky|first=Nicholas|title=The Basics of Game Theory and Associated Games|url=https://issuu.com/johnsonnick895/docs/game_theory_paper|accessdate=11 February 2014}}</ref>  In reality, humans display a [[systemic bias]] towards cooperative behavior in this and similar games despite what is predicted by simple models of "rational" self-interested action.<ref name = Fehr>{{cite journal | last1=Fehr | first1= Ernst | last2=Fischbacher | first2=Urs  | date= Oct 23, 2003 | title=The Nature of human altruism |journal=Nature | volume=425 | pages=785–91 | doi=10.1038/nature02043 | url=http://www.iwp.jku.at/born/mpwfst/04/nature02043_f_born.pdf | accessdate=February 27, 2013 | pmid=14574401 | issue=6960|bibcode = 2003Natur.425..785F }}</ref><ref name = Amos>{{cite book | title=Preference, belief, and similarity: selected writings. | publisher=Massachusetts Institute of Technology Press | first1= Amos | last1=Tversky | first2=Eldar | last2=Shafir | url=http://cseweb.ucsd.edu/~gary/PAPER-SUGGESTIONS/Preference,%20Belief,%20and%20Similarity%20Selected%20Writings%20(Bradford%20Books).pdf  | year=2004 | isbn=9780262700931 | accessdate=February 27, 2013}}</ref><ref name="Ahn">{{cite journal |last1 = Toh-Kyeong|first1 = Ahn|last2 = Ostrom|first2 = Elinor|last3 = Walker|first3 = James|date = Sep 5, 2002|title = Incorporating Motivational Heterogeneity into Game-Theoretic Models of Collective Action|journal = Public Choice|volume = 117|issue = 3–4|pages = 295–314|doi =10.1023/b:puch.0000003739.54365.fd |url = http://www.indiana.edu/~workshop/seminars/papers/ahnostromwalker_092402.pdf|accessdate = June 27, 2015|hdl = 10535/4697}}</ref><ref name="Hessel">{{cite journal|last1 = Oosterbeek|first1 = Hessel|last2 = Sloof|first2 = Randolph|last3 = Van de Kuilen|first3 = Gus|date = Dec 3, 2003|title = Cultural Differences in Ultimatum Game Experiments: Evidence from a Meta-Analysis|journal = Experimental Economics|volume = 7|issue = 2|pages = 171–88|doi = 10.1023/B:EXEC.0000026978.14316.74|url = http://www.econ.nagoya-cu.ac.jp/~yhamagu/ultimatum.pdf|accessdate = February 27, 2013|url-status = dead|archiveurl = https://web.archive.org/web/20130512175243/http://www.econ.nagoya-cu.ac.jp/~yhamagu/ultimatum.pdf|archivedate = May 12, 2013}}</ref> This bias towards cooperation has been known since the test was first conducted at RAND; the secretaries involved trusted each other and worked together for the best common outcome.<ref>{{Cite book | url=https://books.google.com/?id=WIhZlB86nJwC&pg=PT96&lpg=PT96&dq=rand+secretaries+prisoner%27s+dilemma#v=onepage |title = Why Most Things Fail|isbn = 9780571266142|last1 = Ormerod|first1 = Paul|date = 2010-12-22}}</ref> The prisoner's dilemma became the focus of extensive experimental research.<ref>Deutsch, M. (1958). Trust and suspicion. Journal of Conflict Resolution, 2(4), 265–279. https://doi.org/10.1177/002200275800200401</ref> <ref>Rapoport, A., & Chammah, A. M. (1965). Prisoner’s Dilemma: A study of conflict and cooperation. Ann Arbor, MI: University of Michigan Press.</ref>

It is implied that the prisoners will have no opportunity to reward or punish their partner other than the prison sentences they get and that their decision will not affect their reputation in the future. Because betraying a partner offers a greater reward than cooperating with them, all purely rational self-interested prisoners will betray the other, meaning the only possible outcome for two purely rational prisoners is for them to betray each other.  In reality, humans display a systemic bias towards cooperative behavior in this and similar games despite what is predicted by simple models of "rational" self-interested action. This bias towards cooperation has been known since the test was first conducted at RAND; the secretaries involved trusted each other and worked together for the best common outcome. The prisoner's dilemma became the focus of extensive experimental research.  

It is implied that the prisoners will have no opportunity to reward or punish their partner other than the prison sentences they get and that their decision will not affect their reputation in the future. Because betraying a partner offers a greater reward than cooperating with them, all purely rational self-interested prisoners will betray the other, meaning the only possible outcome for two purely rational prisoners is for them to betray each other.  In reality, humans display a systemic bias towards cooperative behavior in this and similar games despite what is predicted by simple models of "rational" self-interested action. This bias towards cooperation has been known since the test was first conducted at RAND; the secretaries involved trusted each other and worked together for the best common outcome. The prisoner's dilemma became the focus of extensive experimental research.  

这意味着，除了判处监禁之外，囚犯没有机会奖励或惩罚他们的伴侣，他们的决定将来不会影响他们的声誉。因为背叛一个合作伙伴比与他们合作能得到更大的回报，所有纯粹理性的、自私自利的囚犯都会背叛对方，这意味着，对于两个纯粹理性的囚犯来说，唯一可能的结果就是他们相互背叛。在现实中，人类在这个和类似的博弈中对合作行为表现出一种系统性的偏见，尽管“理性”自利行为的简单模型已经预测到了这一点。自从兰德首次进行这项测试以来，这种对合作的偏见就已经为人所知; 参与测试的秘书们相互信任，为了最佳的共同结果而共同努力。囚徒困境成为广泛的实验研究的焦点。

这意味着，除了监禁刑罚之外，囚犯没有机会奖励或惩罚他们的同伴，他们的决定也不会影响他们未来的声誉。因为背叛一个同伴比与他们合作能得到更大的回报，所以所有纯粹理性的、自私自利的囚犯都会背叛对方，这意味着，对于两个纯粹理性的囚犯来说，唯一可能的结果就是他们相互背叛。在现实中，尽管“理性”自利行为的简单模型已经预测到了这一点，人类在这种和类似的博弈中对合作行为依然表现出一种系统性的偏见。自从在兰德公司首次进行这项测试以来，这种对合作的偏见就已经为人所知; 参与测试的秘书们相互信任，为了最佳的共同结果而共同努力。囚徒困境成为大量实验研究的焦点。

An extended "iterated" version of the game also exists. In this version, the classic game is played repeatedly between the same prisoners, who continuously have the opportunity to penalize the other for previous decisions. If the number of times the game will be played is known to the players, then (by backward induction) two classically rational players will betray each other repeatedly, for the same reasons as the single-shot variant. In an infinite or unknown length game there is no fixed optimum strategy, and prisoner's dilemma tournaments have been held to compete and test algorithms for such cases.

An extended "iterated" version of the game also exists. In this version, the classic game is played repeatedly between the same prisoners, who continuously have the opportunity to penalize the other for previous decisions. If the number of times the game will be played is known to the players, then (by backward induction) two classically rational players will betray each other repeatedly, for the same reasons as the single-shot variant. In an infinite or unknown length game there is no fixed optimum strategy, and prisoner's dilemma tournaments have been held to compete and test algorithms for such cases.

一个扩展的“迭代”版本的游戏也存在。在这个版本中，经典的游戏在同一个囚犯之间重复进行，他们不断有机会因为以前的决定而惩罚另一个。如果玩家知道游戏的次数，那么(到2010年逆向归纳法)两个经典理性的玩家就会因为和单杆变体相同的原因反复背叛对方。在无限长或未知长度的博弈中，没有固定的最优策略，囚徒困境竞赛被用来竞争和检验这种情况下的算法。

一个扩展的“迭代”版本的博弈由此衍生出来。在这个版本中，经典博弈会在在同一组囚犯之间重复进行，他们不断有机会因为以前的决定而惩罚另一个。如果参与者知道博弈的次数，那么(通过逆向归纳法)两个经典理性的玩家就会因为和在单次博弈相同的原因反复背叛对方。在无限次或未知次数的博弈中，没有固定的最优策略，囚徒困境竞赛因而能被用来竞争并且检验这种情况下的算法。

The prisoner's dilemma game can be used as a model for many real world situations involving cooperative behavior. In casual usage, the label "prisoner's dilemma" may be applied to situations not strictly matching the formal criteria of the classic or iterative games: for instance, those in which two entities could gain important benefits from cooperating or suffer from the failure to do so, but find it difficult or expensive—not necessarily impossible—to coordinate their activities.

The prisoner's dilemma game can be used as a model for many real world situations involving cooperative behavior. In casual usage, the label "prisoner's dilemma" may be applied to situations not strictly matching the formal criteria of the classic or iterative games: for instance, those in which two entities could gain important benefits from cooperating or suffer from the failure to do so, but find it difficult or expensive—not necessarily impossible—to coordinate their activities.

囚徒困境博弈可以作为许多现实世界中涉及合作行为的模型。在临时用法中，”囚徒困境”一词可适用于不严格符合传统或迭代游戏的正式标准的情况: 例如，两个实体可以从合作中获得重要利益或因未能合作而遭受损失，但发现协调其活动很困难或代价昂贵ー不一定不可能。

囚徒困境博弈可以作为许多现实世界中涉及合作行为的模型。在非正式用法中，”囚徒困境”一词可适用于不严格符合传统或迭代博弈的正式标准的情况: 例如，两个实体可以从合作中获得巨大利益或者会因为不能合作而遭受损失，但却发现协调其活动很困难或代价昂贵（并非不可能存在这种情况）。