# How to Win At Rock, Paper, Scissors With Science

physics.soc-ph. Mathematical modelling of Rock-Paper-Scissors.(A) Matrix of outcomes (B) Non-transitive dominance relations. (C) The social state plane for population N=6 transitions at game rounds t = 1, 2, 3
A study of common strategies playing Rock, Paper, Scissors has provided advice on the best way to win, at least as long as your opponent has not read the same study.

Rock, Paper, Scissors might once have been a game for children, but these days there are leagues for serious money and even a “world championship”. Meanwhile male lizards have been discovered to be playing the same game. If everyone was random in the way they played the game it would simply be a matter of chance who won. While people will throw away fortunes on games of chance, one with only three options would probably not hold attention. However, humans are not random number generating machines. There are patterns in how we play, and someone who can pick such patterns can gain an advantage.

There are already advice pages on the web for beating common strategies, but it is unclear how reliable their recommendations are, other than those that are simply logic. Now peer reviewed science has something to offer.

A study of 300 volunteers, paid extra if they win to ensure effort, found patterns which have been reported in the unlikely sounding choice of Physics and Society. Players were filmed over repeated rounds, swapping opponents as they went. Players were slightly more likely to repeat a winning throw, and if they lost too many times with a particular choice they would give up on it. So the best thing to do after losing was to use choose the option that would have beaten the winner, while after winning it was advisable to go with a choice that would beat one of the options the loser had not used.

Psychologically this is hardly surprising, at least for new players. We are geared to continue strategies that succeed and change those that haven't worked, even if we rationally know that circumstances might be different this time. Nobel Prize winning economist Paul Krugman pointed out that the same tendencies drive stock market bubbles and may have roots in what worked for our paleolithic ancestors.

Nevertheless, some people might anticipate such strategies and adjust their game accordingly. Others might observe, consciously or not, the way others play and adapt. Zhijian Wang, Bing Xu and Hai-Jun Zhou of Zheijang University, China, found that if either of these were happening among the group they studied it was rare enough to be outweighed by those going with their reflexes.

However, while the authors suggest their work provides an advantageous strategy for players the group they studied were selected from students at the university and some behaviors may be culturally specific. Moreover, experienced players may act differently from those volunteering for a few yuan, so take care before trying these moves out against a shark.