Social, Economic and Organizational Psychology, Leiden University, Leiden, The Netherlands.
Center for Research in Experimental Economics and Political Decision Making (CREED), University of Amsterdam, Amsterdam, The Netherlands.
Philos Trans R Soc Lond B Biol Sci. 2022 May 23;377(1851):20210147. doi: 10.1098/rstb.2021.0147. Epub 2022 Apr 4.
Peaceful coexistence and trade among human groups can be fragile and intergroup relations frequently transition to violent exchange and conflict. Here we specify how exogenous changes in groups' environment and ensuing carrying-capacity stress can increase individual participation in intergroup conflict, and out-group aggression in particular. In two intergroup contest experiments, individuals could contribute private resources to out-group aggression (versus in-group defense). Environmental unpredictability, induced by making non-invested resources subject to risk of destruction (versus not), created psychological stress and increased participation in and coordination of out-group attacks. Archival analyses of interstate conflicts showed, likewise, that sovereign states engage in revisionist warfare more when their pre-conflict economic and climatic environment were more volatile and unpredictable. Given that participation in conflict is wasteful, environmental unpredictability not only made groups more often victorious but also less wealthy. Macro-level changes in the natural and economic environment can be a root cause of out-group aggression and turn benign intergroup relations violent. This article is part of the theme issue 'Intergroup conflict across taxa'.
人类群体之间的和平共处和贸易可能是脆弱的，群体间的关系经常会转变为暴力交流和冲突。在这里，我们具体说明了群体环境的外生变化以及随之而来的承载能力压力如何增加个体参与群体间冲突，特别是对外群体的攻击。在两个群体间竞争实验中，个体可以将私人资源用于对外群体的攻击（而不是对内群体的防御）。通过使未投资的资源面临被破坏的风险（而不是不面临），环境的不可预测性会产生心理压力，并增加对外群体攻击的参与度和协调性。对国家间冲突的档案分析同样表明，当主权国家在冲突前的经济和气候环境更加不稳定和不可预测时，它们更有可能发动修正主义战争。鉴于参与冲突是浪费的，环境的不可预测性不仅使群体更容易获胜，而且使群体更贫穷。自然和经济环境的宏观变化可能是对外群体攻击的根源，并使良性的群体间关系变得暴力。本文是主题为“跨物种群体冲突”的一部分。
