A Win in the Hand: New Study Identifies Rock-Paper-Scissors Trends
May 8, 2014
A group of scientists has gotten serious about Rock-Paper-Scissors.
Applying a good amount of observation to the ancient hand-based game, researchers from Zhejiang University in Hangzhou, China, crunched the numbers from 300 rounds of 360 university students trying their hands at the three-outcomes game and found that it was possible to more accurately predict what move players should make in subsequent games, based on what moves the other player had made before.
The researchers split the students into 60 groups of 6, and each student played each of the 300 rounds only against the other five players in his or her group. The researchers paid each student a small sum of money for each "win," to encourage the students to give their best efforts.
The study showed that players who won a round were more likely to stick with their choice for the following round and that players who lost a round were more likely to switch choices. For example, a player who chose "rock" and won would be more likely to choose "rock" again the following round, to stay with the winning option; on the flip side, a player who chose "scissors" and lost would be more likely to choose "rock" or "paper" the following round, to avoid the losing option of the previous round.
This is not the first study to come to such a conclusion. Research a few years ago found that rhesus monkeys employed the same strategy to a limited extent, copying the winning option in subsequent rounds. Many studies on humans have found the same results. This latest study went one further, though.
The Zhejiang University scientists also found that players who lost one round and then switched options for the next round were more likely to choose the option that came next in the traditional order of the name of the game, so a player who chose "rock" and lost was more likely to choose "paper" than "scissors" in the round immediately following the round in which "rock" was the losing option. Further, a player who chose "rock" and lost and then "paper" and then lost was much more likely to choose "scissors" in the round right after that.
The game itself is thought to have originated in ancient China, during the Han Dynasty.
The study is in the e-print repository of Cornell University at arXiv.org.