Rock-paper-scissors is generally considered to be a game of chance, but a new study analyzing the play of 360 students at a rock-paper-scissors tournament at Zhejiang University in China has revealed subtle patterns that players exhibit which can be anticipated. Taking these results into consideration, scientists believe they have uncovered the ideal rock-paper-scissors winning strategy, reports the BBC.
According to classical game theory, or the mathematical study of strategic decision making, players maximize their odds of winning by playing rock, paper or scissors totally randomly, to prevent their opponents from anticipating any patterns. Most competitors in rock-paper-scissors tournaments do this instinctually, and scientists found that players tended to follow this strategy in the Chinese tournament as well.
But while players tended to choose each of the three actions about a third of the time, researchers noticed a surprising pattern of behavior emerge. When players won a round, they tended to repeat their winning rock, paper or scissors more often than would be expected at random. Meanwhile, losers tended to switch to a different action. Even more startling, the action that losers tended to switch to followed the most obvious pattern of all-- the order of the name of the game.
In other words, if a player lost with rock, it increased the likelihood that they would play paper in the next round. If they lost with paper, they would switch to scissors. Researchers believe that this "win-stay, lose-shift" strategy may be hard-wired into the human brain.
"Whether conditional response is a basic decision-making mechanism of the human brain or just a consequence of more fundamental neural mechanisms is a challenging question for future studies," wrote the study's authors.
A player aware of these patterns could potentially game the system. Of course, though, the game would probably collapse right back into a game of chance among professional players. That is, if both players are aware of how to employ this "winning" strategy, then they'd both be better off just going back to playing randomly.
The Chinese scientists next plan to investigate the seemingly irrational choices that players make when competing, with the hope of revealing the underlying psychological patterns that underlie them.
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