Paper-Rock-Scissors: an exploration of the dynamics of players’ strategies

Abstract

This research contributes to the understanding of dynamic decision making behavior in adversarial repeated interactions. Using a well-known competitive game, Rock-Paper-Scissors in a two-player experiment, we collected data of repeated play in pairs over many trials. We design a payoff matrix that allows us to distinguish the optimal (Nash) behavior from random behavior. Our analyses indicate that participants do not play in agreement with Nash or random. We also do not find evidence of the cyclic behavior suggested in the literature. Interestingly, human behavior is very heterogeneous. While some players follow the common “Win-Stay/Lose-Shift” heuristic, many others also follow a "Win-Shift/Lose-Stay” heuristic. We summarize our conclusions for the study of the dynamics of behavior in adversarial situations.