Ichinose Genki, Sayama Hiroki
1] Anan National College of Technology, 265 Aoki Minobayashi, Anan, Tokushima 774-0017, Japan [2] Collective Dynamics of Complex Systems Research Group, Binghamton University, State University of New York, Binghamton, NY 13902-6000, USA.
Collective Dynamics of Complex Systems Research Group, Binghamton University, State University of New York, Binghamton, NY 13902-6000, USA.
Sci Rep. 2014 May 29;4:5104. doi: 10.1038/srep05104.
The Ultimatum Game (UG) is an economic game where two players (proposer and responder) decide how to split a certain amount of money. While traditional economic theories based on rational decision making predict that the proposer should make a minimal offer and the responder should accept it, human subjects tend to behave more fairly in UG. Previous studies suggested that extra information such as reputation, empathy, or spatial structure is needed for fairness to evolve in UG. Here we show that fairness can evolve without additional information if players make decisions probabilistically and may continue interactions when the offer is rejected, which we call the Not Quite Ultimatum Game (NQUG). Evolutionary simulations of NQUG showed that the probabilistic decision making contributes to the increase of proposers' offer amounts to avoid rejection, while the repetition of the game works to responders' advantage because they can wait until a good offer comes. These simple extensions greatly promote evolution of fairness in both proposers' offers and responders' acceptance thresholds.
最后通牒博弈（UG）是一种经济博弈，其中两名参与者（提议者和响应者）决定如何分配一定数量的金钱。虽然基于理性决策的传统经济理论预测提议者应提出最低报价，而响应者应接受该报价，但人类受试者在最后通牒博弈中往往表现得更公平。先前的研究表明，在最后通牒博弈中，公平性的演变需要诸如声誉、同理心或空间结构等额外信息。在这里，我们表明，如果参与者进行概率决策，并且在报价被拒绝时可能继续互动，公平性可以在没有额外信息的情况下演变，我们将其称为不完全最后通牒博弈（NQUG）。不完全最后通牒博弈的进化模拟表明，概率决策有助于提高提议者的报价金额以避免被拒绝，而博弈的重复对响应者有利，因为他们可以等到一个好的报价出现。这些简单的扩展极大地促进了提议者报价和响应者接受阈值方面公平性的演变。
