The question of how to win at rock-paper-scissors has, believe it or not, plagued mathematicians¹ and game theorists for some time. While they previously² had devised a theoretical answer to the question, an experiment by Zhijian Wang at Zhejiang University in China (PDF) that used real players has revealed an interesting wrinkle to the original theory.

如何在石头剪刀布的游戏中取得胜利？这个问题长久以来一直困扰着数学家和博弈论理论家，信不信由你。前人已经就这个问题建立了一套理论，而中国浙江大学一位名叫王志坚的研究员则通过一项真人实验对前人的理论进行了十分有趣的拓展。

In the experiment, Zhijian noticed that winning players tended to stick with their winning strategy, while losers tended to switch to the next strategy in the sequence of rock-paper-scissors, following what he calls "persistent³ cyclic flows".

在实验过程中，王志坚发现，在石头剪刀布的游戏中，取胜的一方往往会坚持自己的求胜策略，而失败的一方则往往会在新一轮中变换自己的游戏策略，其中起作用的是一种“惯性循环”意识。

While the Nash Equilibrium⁴ should be the best strategy in real life, Zhijian found a decidedly different pattern when he and some other researchers recruited 72 students to play the game. They divided the students into 12 groups of six players and had them each play 300 rounds of rock-paper-scissors against each other. Zhijian also added a payout in proportion to the number of victories.

人们往往认为“纳什均衡原理”是现实生活中玩石头剪刀布的最佳策略，而王志坚和自己的研究伙伴挑选了72位学生进行试验，结果发现了一个与纳什均衡具有明显差异的致胜模式。他们将这些学生分成12个组，每组6人，让每组的组员一对一玩300回合的石头剪刀布。王志坚还根据游戏获胜的几率对学生们支付奖金。

The pattern that Zhijian discovered - winners repeating their strategy and losers moving to the next strategy in the sequence - is called a 'conditional⁵ response' in game theory. The researchers have theorised that the response may be hard-wired into the brain, a question they intend to investigate with further experiments.

王志坚发现的这个规律——重复自己游戏模式的人获胜，而下一局中变换另一游戏模式的人失败——在博弈论中被称为“条件反应”。研究者们作出设想，或许这种反应模式是深植在人的大脑结构中的，这个问题他们将进一步展开实验进行研究。