Department of Psychology, University of Guelph, 50 Stone Road E., Guelph, ON, Canada, N1G 2W1.
Department of Anthropology, Pennsylvania State University, PA, USA.
Philos Trans R Soc Lond B Biol Sci. 2021 Nov 22;376(1838):20200292. doi: 10.1098/rstb.2020.0292. Epub 2021 Oct 4.
Social organisms often need to know how much to trust others to cooperate. Organisms can expect cooperation from another organism that depends on them (i.e. stake or fitness interdependence), but how do individuals assess fitness interdependence? Here, we extend fitness interdependence into a signalling context: costly helping behaviour can honestly signal one's stake in others, such that those who help are trusted more. We present a mathematical model in which agents help others based on their stake in the recipient's welfare, and recipients use that information to assess whom to trust. At equilibrium, helping is a costly signal of stake: helping is worthwhile for those who value the recipient (and thus will repay any trust), but is not worthwhile for those who do not value the recipient (and thus will betray the trust). Recipients demand signals when they value the signallers less and when the cost of betrayed trust is higher; signal costs are higher when signallers have more incentive to defect. Signalling systems are more likely when the trust games resemble Prisoner's Dilemmas, Stag Hunts or Harmony Games, and are less likely in Snowdrift Games. Furthermore, we find that honest signals need not benefit recipients and can even occur between hostile parties. By signalling their interdependence, organisms benefit from increased trust, even when no future interactions will occur. This article is part of the theme issue 'The language of cooperation: reputation and honest signalling'.
社会生物经常需要知道要信任多少人才能合作。生物体可以期望依赖于它们的另一个生物体进行合作（即利益或适应度相互依存），但个体如何评估适应度相互依存？在这里，我们将适应度相互依存扩展到信号传递的背景中：有代价的帮助行为可以诚实地表明一个人对他人的利益的投入，从而使那些帮助他人的人更受信任。我们提出了一个数学模型，其中代理人根据对接受者福利的利益来帮助他人，而接受者则利用这些信息来评估信任谁。在均衡状态下，帮助是利益投入的昂贵信号：那些重视接受者（因此会回报任何信任）的人会觉得帮助是值得的，但那些不重视接受者的人（因此会背叛信任）则不会觉得帮助是值得的。当接受者对信号发送者的重视程度较低且被背叛的信任成本较高时，他们会要求信号；当信号发送者更有动机违约时，信号成本会更高。当信任博弈类似于囚徒困境、 stag hunt 或和谐博弈时，信号系统更有可能发生，而当信任博弈类似于 snowdrift game 时，信号系统不太可能发生。此外，我们发现，诚实的信号不一定对接受者有利，甚至可能发生在敌对双方之间。通过发出他们相互依存的信号，生物体受益于信任度的提高，即使没有未来的相互作用发生。本文是主题为“合作的语言：声誉与诚实的信号”的一部分。
