经济学人下载:合作关系的演变 社交网络驯服欺骗者

Science and Technolgy
科技

The evolution of co-operation
合作关系的演变

Make or break?
建立还是终止？

Social networking tames cheats
社交网络驯服欺骗者

HOW people collaborate, in the face of numerous temptations to cheat, is an important field of psychological and economic research.
在无数互相欺骗的诱惑中，人们如何建立合作关系？这是心理和经济学研究的一个很重要的领域。

A lot of this research focuses on the "tit-for-tat" theory of co-operation:
关于这个领域的很多研究都集中在"以牙还牙"的合作理论：

that humans are disposed, when dealing with another person, to behave in a generous manner until that other person shows himself not to be generous. At this point co-operation is withdrawn.
那就是，一个人在处理和另外一个人的关系时，开始都会选择慷慨的态度，直到对方显露出不慷慨的迹象，这个时候也是合作关系终止的时候。

Fool me once, in other words, shame on you. Fool me twice, shame on me.
用另外一种话说，就是"欺我一回，罪过在你，欺我二回，罪过在我。"

When he encounters such a withdrawal of collaboration, the theory goes, the malefactor will learn the error of his ways and become a more co-operative individual.
当遭遇这样的一次合作终止，如理论所说，作为合作规则的破坏者，他会开始反省他处事的过错，并且开始变成更加乐于合作的个体。

And there is experimental evidence, based on specially designed games, that tit-for-tat does work for pairs of people. Human societies, though, are more complex than mere dyads.
在特殊设计的游戏基础上得出的实验证据显示，"以牙还牙"理论在两个人的关系中确实奏效。

And until recently, it has been difficult to model that complexity in the laboratory.
然而人类社会关系远比两两之间更为复杂。

But a paper published this week in the Proceedings of the National Academy of Sciences by Nicholas Christakis and his colleagues at Harvard has changed that.
直到最近，这种复杂的关系还难以在实验室中模拟出来。但在这周，哈佛大学Nicholas Christakis和他的同事在"国家科学院院刊"上发表的论文改变了这个状况。

Dr Christakis arranged for a collaboration-testing game to be played over the web, with many participants.
Christakis博士在网上安排了一场多人参与的实验测试游戏。

As a result, he and his team have gained a more sophisticated insight into the way co-operation develops.
经过这个实验，他和同事对人际合作发展方式有了更深的理解。

Dr Christakis used what is known as a public-goods game for his experiment.
Christakis博士在这个实验中采用称为"公共利益"的游戏。

At the beginning of such a game, points are doled out to each participant. During every round, players are given the opportunity to donate points to their neighbours.
游戏之初，每个参与者分发到少量的分数。在接下来每一轮游戏中，参与者都有机会赠送分数给他的邻居。

Points so donated are augmented by an equal number from the masters of the game.
赠送者的分数能够在游戏管理者那里得到与之舍出分数相等量的增长。

If everyone co-operates, then, everyone ends up richer. A "defector" who refuses to donate to his co-operating neighbours will, however, benefit at the expense of those neighbours.
如果参与者都合作的话，每个人最终分数都会比最开始的多。而拒绝赠送分数的"破坏者"却从他邻居们的损失中获益。

At the game's end, the points are converted into real money, to ensure that proper incentives are in place.
为了保证适当的奖励到位，游戏后这些分数可以变换成钱。

To play his large-scale public-goods game, Dr Christakis recruited 785 volunteers via Mechanical Turk—a service provided by Amazon, an online retailer, that works by farming out small tasks to an army of individual workers.
为了展开这个大型的"公共利益"游戏，Christakis博士通过网上零售商亚马逊提供的土耳其机器人网络服务招收了785名志愿者。这是个发包小任务给个体劳动队伍的服务网络。

Each volunteer was randomly assigned links to, on average, eight other players. Together, they played repeated rounds of one of three variations of the game.
在这个网络上，每个志愿者大约和八个随机分配的参与者连接组队，并根据三种设定的游戏模式重复开展。

In the first, participants always interacted with the same group of people.
第一种模式，参与者总是和同一组人合作。

In the second, the connections were randomly reshuffled after each round.
第二种模式，每一轮游戏后合作者都随机重组。

In the final version, one-third of the possible pairings between participants were chosen at random after each round (such pairs may or may not, therefore, have been dealing with each other in the previous round).
最后一种，每一轮后，三分之一的组合将被选中并随机重组（因此这些重组的组合中可能有人在前面的游戏中已经合作过了。)。

One player from each pair was first told or reminded of how the other had behaved in the previous round, and was then asked whether he wanted to break his connection with that player, if he already had one, or form a new connection, if he had not.
组合中一人会被告知或提醒他的合作对象在前面一轮游戏中的表现，他可以选择是否解除和这个人的合作，如果他已经有一个合作对象的话；如果他没有合作对象，他则可以选择是否建立新的合作联系。

In all versions of the game, roughly 60% of players started out co-operating.
在所有三种模式中，大约60%的参与者最开始都是遵守合作规则。

However, in the first two, this decreased over time as the pernicious influence of the freeloaders spread.
可是头两种模式中，随着吃白食恶劣影响的扩展，遵守的人数也跟着下降。

The larger the fraction of a subject's partners who defected in a given round, the less likely that person was to co-operate in the next—classical tit-for-tat.
一个参与者合作过的对象中破坏规则的人数比例越高，这个参与者在下一轮的游戏中越不可能遵守合作规则-典型的"以牙还牙"。

However, this tit-for-tat retaliation was not enough to save co-operation, and after a dozen rounds only 10-20% of the players were still willing to co-operate.
然后，这种"以牙还牙"的报复并不能拯救合作的持续，在十几轮游戏后，只有10-20%的参与者还愿意合作。

In the variant where participants had some choice over whom they interacted with, though, the amount of co-operation stayed stable as the rounds progressed.
然而在参与者可以选择合作对象的模式中，合作的人数随着游戏的进行保持稳定。

When Dr Christakis and his team looked at how the relationships between players were evolving in this third version, they found that connections between two co-operators were much more likely to be maintained than links that involved a defector.
Christakis博士和他的团队观察第三种模式中参与者的关系如何演变时，他们发现没有碰到过破坏者的组合更容易保持合作。

Over time, the co-operators accumulated more social connections than the defectors did.
在游戏中，合作者比破坏者积累了更多的合作关系。

Furthermore, as they were shunned, the defectors began to change their behaviour.
而且，被拒绝后，破坏者也开始改变他们的行为。

A defector's likelihood of switching to co-operation increased with the number of players who had broken links with him in the previous round.
在前面一轮游戏中和他中止合作的人越多，他越有可能转向合作者。

Unlike straightforward tit-for-tat, social retaliation was having a marked effect.
不像简单的以牙还牙，社会报复有一个标记作用。

The next question, then, is whether such a mechanism holds outside the laboratory.
接下来的问题是，这样的一个机制在实验室外是否可行？

To find out, Dr Christakis has forged links with some anthropologists.
为了找出答案，Christakis博士已经和一些人类学家取得联系。

They hope to report the answer soon.
他们希望能够很快得出结论。