If you have ever had to decide on an outcome with a friend, chances are you have done it by playing rock-paper-scissors, the fun hand game where players simultaneously form one of the three shapes with an outstretched hand. Like most people, you probably thought that the game is designed for a random outcome, one in which neither player has an advantage. Turns out you were wrong. According to scientists from China's Zhejiang University, there is a method to this madness - one that can be easily mastered so that you never lose a rock-paper-scissors duel again.
The researchers whose study 'Social cycling and conditional responses in the Rock-Paper-Scissors game', was published on April 21st, in Cornell University's e-print repository, arXiv.org, began their investigation by recruiting 360 Zhejiang University students to play the game. The students were split up into 60 groups of six people, with each student playing 300 rounds against the other five group members. To encourage students to try their best, the scientists paid them for every individual victory.
In the beginning stages of each round, rock, paper, and scissors were chosen about the same number of times. However, the randomness of the results began to fade as the tournaments progressed and the scientists started to notice a pattern. Players that had won the previous round, were prone to choosing the winning option in the next round to try continue their winning streak. On the other hand those that had lost, immediately switched to a different option - usually the one that came next in the order of the game's name. That means a player who had lost with rock would likely choose paper next and then move on to scissors, if that did not work. This led the scientists to conclude that if one pays close attention to their opponent's choices, it would be easy to anticipate their next move and ensure a victory. Of course, this trend is only exploitable if the outcome is based on 'best of three' results.
Prior to this study, researchers had believed rock-paper-scissors operated on the "Nash equilibrium," a game theory principle which stipulates that players tend to choose each of the three options equally, over a period of time.
Of course, this revelation may come as no surprise to those high-skilled rock-paper-scissors players that have used this strategy for many years. The good news is that you too can now be amongst those elite few, and ensure that the decision always tilts in your favor. Good luck!
Rock-paper-scissors is an ancient game, the origins of which can be traced all the way back to the Chinese Han Dynasty (206BC-220AD). Called shoushiling or hand command, it was soon imported by Japan and by the 20th century, the rest of the world. It became so popular that in 2002, a special body - the World Rock Paper Scissors Society was established to create a set of rules for International play and also oversea the International World Championships. While those have come to a halt since the death of the society's chairman in 2010, many countries have continued the tradition with their own regional championships.
Resources: ctnews.com, huffingtonpost.com