近几年，从诺贝尔奖到MBA核心课程，似乎言必称博弈论。找了一篇外刊中关于博弈论的一段文字，并斗胆去做翻译。

谢谢Howard，Renee等对我译文的指点，wisdom lies elsewhere. 我们在做一件注定要受批评的事情。但受益的肯定会包括我们自己。

Dr. Kurzban and Dr. Houser were interested in the outcomes of what are known as public-goods games. In their particular case they chose a game that involved four people who had never met (and who interacted via a computer) making decisions about their own self-interest that involved assessing the behavior of others. Each player was given a number of virtual tokens*, redeemable* for money at the end of the game. A player could keep some or all of these tokens. Any not kept were put into a pool, to be shared among group members. After the initial contributions had been made, the game continued for a random number of turns, with each player, in turn, being able to add to or subtract from his contribution to the pool. When the game ended, the value of the pool was doubled, and the new, doubled value was divided into four equal parts and given to the players, along with the value of any tokens they had held on to. If everybody trusts each other, therefore, they will all be able to double their money. But a sucker *who puts all his money into the pool when no one else has contributed at all will end up with only half what he started with.

Kurzban 和Houser博士致力于研究“公共物品博弈”的调查结果。具体说来，他们选出四个素未谋面的人，通过电脑互动，参与游戏，彼此通过揣测他人的行为作出相应决策，来谋取个人利益。游戏伊始，每个玩家都分得一定数量的代币，在游戏结束时可以兑换成现金带走。玩家可选择保留全部代币，也可自愿将部分代币放入四人共用的基金，并在游戏结束时与其他三人平分基金中的金额。游戏可以进行若干轮，各玩家按先后顺序，或收回或追加注入基金的代币。游戏结束时，基金的数目将翻番，再均分给四位玩家，再加上每个玩家手里留着的代币即为最后所得。如果每位玩家都能相互信任，那么每个人都能财富翻番。但如果有一个“傻瓜”将全部代币注入基金，而其他三人却都一毛不拔，那么这个倒霉蛋的财富最后就要减少一半。

This is a typical example of the sort of game that economists investigating game theory revel in, and both theory and practice suggests that a player can take one of three approaches in such a game: co-operate with his opponents to maximize group benefits (but at the risk of being suckered), free-riders* (i.e., try to sucker co-operators) or reciprocate (i.e., co-operate with those who show signs of being co-operative, but not with free-riders). Previous investigations of such strategies, though, have focused mainly on two-player games, in which strategy need be developed only in a quite simple context. The situation Dr. Kurzban and Dr. Houser created was a little more like a real life. They wanted to see whether the behavioral types were clear-cut in the face of multiple opponents who might be playing different strategies, whether those types were stable, and whether they had the same average pay-off.

上述案例即为研究博弈理论的经济学家们热衷的典型博弈游戏，且理论和实践上都证明，游戏玩家可在博弈过程中会采取下列三种策略之一：“合作型”（总是与对手合作以期实现最大得益，但可能被骗），“投机型”（总是试图通过欺骗合作型玩家而得益），和“互惠型”（仅与那些有合作意向的玩家合作，不与投机型为伍）。但以往的研究仅限于两人参加博弈游戏，博弈环境相对简单。Kurzban 和Houser博士设置的情景则更贴近真实生活。他们所关注的是，在多名玩家各自可能采取不同策略的博弈环境中，各玩家的行为方式是否泾渭分明，是否始终如一，不同的策略又是否会带来相同的平均得益。

The last point is crucial to the theory of evolutionarily stable strategies. Individual strategies are not expected to be equally represented in a population. Instead, they should appear in proportions that equalize their pay-offs to those who play them. A strategy can be advantageous when rare and disadvantageous when common. The proportions in the population when all strategies are equally advantageous represent the equilibrium.

平均得益是否相同，这点对于确定进化稳定策略理论至关重要。在某特定群体中，采用各博弈策略的人数不尽相同。事实上，任何个体策略的分布都应该按照某个比例，这样该策略带来的得益均分给对应数量的玩家后，各策略所获平均得益都相等。如果只有少数人采用某策略，得益自然就高，而一旦普遍采用，得益自然就低。当各策略带来的平均得益都相等时，采取这些策略的个体人数之间的比例，即代表了进化稳定均衡。

posted on 2006-05-26 16:07 昂立HR 阅读(1241) 评论(0)  编辑  收藏 所属分类: 王晓波 网摘收藏