title: Social cycling and conditional responses in the Rock-Paper-Scissors game.
abstract: How humans make decisions in non-cooperative strategic interactions is a big question. For the fundamental Rock-Paper-Scissors (RPS) model game system, classic Nash equilibrium (NE) theory predicts that players randomize completely their action choices to avoid being exploited, while evolutionary game theory of bounded rationality in general predicts persistent cyclic motions, especially in finite populations. However as empirical studies have been relatively sparse, it is still a controversial issue as to which theoretical framework is more appropriate to describe decision-making of human subjects. Here we observe population-level persistent cyclic motions in a laboratory experiment of the discrete-time iterated RPS game under the traditional random pairwise-matching protocol. This collective behavior contradicts with the NE theory but is quantitatively explained, without any adjustable parameter, by a microscopic model of win-lose-tie conditional response. Theoretical calculations suggest that if all players adopt the same optimized conditional response strategy, their accumulated payoff will be much higher than the reference value of the NE mixed strategy. Our work demonstrates the feasibility of understanding human competition behaviors from the angle of non-equilibrium statistical physics.
authors: 1] Experimental Social Science Laboratory, Zhejiang University, Hangzhou 310058, China [2].
authors: Zhijian
authors: Z
authors: Wang
authors: 1] Public Administration College, Zhejiang Gongshang University, Hangzhou 310018, China [2] Experimental Social Science Laboratory, Zhejiang University, Hangzhou 310058, China [3].
authors: Bin
authors: B
authors: Xu
authors: State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors: Hai-Jun
authors: HJ
authors: Zhou
mesh_terms: D003214:Conditioning, Classical; D003299:Cooperative Behavior; D003657:Decision Making; D005260:Female; D005716:Game Theory; D006801:Humans; D008297:Male; D008960:Models, Psychological; D008962:Models, Theoretical; D055815:Young Adult