The age old game of rock-paper-scissors has led to so many decision in my life! The game is as ancient as the Chinese Han Dynasty around 220 B.C., and is usually used as a tiebreaker and in the event of inability to come to a decision more logically.
But a new research suggests that the game might not be as random as we have thought. Scientists from Zhejiang University in China has conducted a revealing study about the mathematical logic behind the game of rock-paper-scissors.
In a large-scale laboratory experiment, the scientists observed patterns of decision-making of the 360 students broken into six groups. The study yielded a microscopic model for the win-lose-tie conditional response, and the players were even paid to win the game just to make sure they were playing seriously.
The study concluded an interesting phenomenon of positive reinforcement, as the player tended to repeat their previous move if they won because of it, while the loser moved on to play a different hand leading to a ‘persistent cyclic motion‘.
This persistent cyclic motion is defined in the paper with an example,
“Players A and B both begin a round by going for a random hand. If player A uses rock and B uses paper, A is the loser. Playing in a second round, A can assume that B will use paper again and intuitively go for scissor in order to win which makes player B the loser. Playing again for a third round, player A can assume that B will use the next strategy in the cycle – scissors – and A will then use rock and wins the game again.”
Mathematically, choosing any move gives you 1/3 chance of winning, since you can either win, a lose, or a tie. But the repeated cycle explained above, also known as Nash’s equilibrium, is based on human being’s tendency to keep repeating or following a winning technique despite the clear evidence of correlation not being the explanation for causation.
This phenomenon can be seen in wearing the “lucky ” hat for your team’s football match to make them win and thinking that uttering a certain prayer way will help you achieve something etc. just because it happened that one random time. This is also known as classical conditioning in the world psychology. The Chinese scientists’ believe this to be the natural instinct of the brain, but say they require further research and experiments to confirm this.
Rock-Paper-Scissors game’s social cycling and conditional responses was published in Nature Research Journal.