Cycle frequency in standard Rock-Paper-Scissors games: Evidence from experimental economics

TL;DR

This study provides experimental evidence of persistent cycles in Rock-Paper-Scissors games, supporting evolutionary game theory predictions over classical game theory, with measurable cycling frequencies explained by a non-equilibrium model.

Contribution

The paper offers the first strong experimental evidence of persistent cycles in RPS games and links these observations to a simple dynamical model, advancing understanding of evolutionary dynamics.

Findings

Strong evidence of persistent cycles in RPS games.

Measured mean cycling frequency of 0.029 periods per round.

Experimental results align with a discrete-time logit dynamical model.

Abstract

The Rock-Paper-Scissors (RPS) game is a widely used model system in game theory. Evolutionary game theory predicts the existence of persistent cycles in the evolutionary trajectories of the RPS game, but experimental evidence has remained to be rather weak. In this work we performed laboratory experiments on the RPS game and analyzed the social-state evolutionary trajectories of twelve populations of N=6 players. We found strong evidence supporting the existence of persistent cycles. The mean cycling frequency was measured to be $0.029 \pm 0.009$ period per experimental round. Our experimental observations can be quantitatively explained by a simple non-equilibrium model, namely the discrete-time logit dynamical process with a noise parameter. Our work therefore favors the evolutionary game theory over the classical game theory for describing the dynamical behavior of the RPS game.