In Brief: How to Win at Rock Paper Scissors

By Norman Chan

It's all about psychology.

MIT Technology Review has details about a recent study carried out at the Zhejiang University in China on rock-paper-scissors strategy. Conventional thinking was that the best strategy for not losing in the long run was to choose your play at random--as defined by the Nash equilibrium mixed strategies solution of game theory. But the research done with 360 students at the university indicated that play choices were conditional and patterns emerged. Specifically, winners of one round tend to stick with the same action, while losers switch to the next action in a sequence (in the order of rock, paper, scissors). The researchers are preparing future studies to determine whether this type of conditional response is a basic decision-making mechanism or a byproduct of fundamental neural mechanism. Gambit play was not taken into consideration.