Sign in with your favourite social login to share, comment and pin your favourites.
Win at rock-paper-scissors
Rock-Paper-Scissors has been played for thousands of years, and the chance of winning has always thought to be one in three. Now scientists in China have discovered a strategy for winning the game.
Predictable patterns emerge
Popular opinion has suggested that the game adheres to the Nash equilibrium, as reported in Technology Review, in which every player chooses their weapon at random with equal probability of winning at the start of each new round. However, Zhijian Wang and friends, of Zhejiang University in China, think there’s more to it, namely that there are predictable patterns that could help clever players gain an advantage.
Gathering 360 students from the university, Zhijian divided them into 60 groups of six players. In each group, the competitors played 300 rounds of the rock-paper-scissors with their actions recorded. Winners were paid in proportion to their number of victories to add an incentive to win.
As expected, on average everyone chose each action about a third of the time, which conforms to the Nash equilibrium. However, when analyzed more closely, Zhijian and his team found that players who win will tend to repeat the same winning action again, while those who lose will switch to the next action in a clockwise direction, where Rock → Paper → Scissors is clockwise.
This, then, is a “win-stay, lose-shift” strategy and a conditional response that has never been observed before when studying the game. When you think about it (we know, easily done now it’s all been explained for us) it’s human nature to stick with a winning strategy and make changes after losses.
We’ve always been fans of the Bart Simpson strategy – “Good ol’ rock. Nuthin’ beats that!” – but it looks like we might have to up our game and start paying more attention.