School of Public Policy, University of Michigan, Ann Arbor, MI 48109;
Biodesign Center for Biocomputing, Security and Society, Arizona State University, Tempe, AZ 85281.
Proc Natl Acad Sci U S A. 2021 Dec 14;118(50). doi: 10.1073/pnas.2102139118.
Extreme polarization can undermine democracy by making compromise impossible and transforming politics into a zero-sum game. "Ideological polarization"-the extent to which political views are widely dispersed-is already strong among elites, but less so among the general public [N. McCarty, , 2019, pp. 50-68]. Strong mutual distrust and hostility between Democrats and Republicans in the United States, combined with the elites' already strong ideological polarization, could lead to increasing ideological polarization among the public. The paper addresses two questions: 1) Is there a level of ideological polarization above which polarization feeds upon itself to become a runaway process? 2) If so, what policy interventions could prevent such dangerous positive feedback loops? To explore these questions, we present an agent-based model of ideological polarization that differentiates between the tendency for two actors to interact ("exposure") and how they respond when interactions occur, positing that interaction between similar actors reduces their difference, while interaction between dissimilar actors increases their difference. Our analysis explores the effects on polarization of different levels of tolerance to other views, responsiveness to other views, exposure to dissimilar actors, multiple ideological dimensions, economic self-interest, and external shocks. The results suggest strategies for preventing, or at least slowing, the development of extreme polarization.
极端的两极分化可能会破坏民主，使妥协变得不可能，并使政治变成一场零和博弈。“意识形态两极分化”——政治观点广泛分散的程度——在精英阶层中已经很严重，但在普通公众中则不那么严重[ N. McCarty,, 2019, pp. 50-68]。美国民主党和共和党之间强烈的相互不信任和敌意，加上精英阶层已经很强的意识形态两极分化，可能导致公众的意识形态两极分化加剧。本文探讨了两个问题：1）是否存在一个两极分化程度的临界点，超过这个临界点，两极分化就会自我强化，形成失控的过程？2）如果是这样，有哪些政策干预可以防止这种危险的正反馈循环？为了探讨这些问题，我们提出了一个基于主体的意识形态极化模型，该模型区分了两个行为体相互作用的倾向（“接触”）和相互作用时的反应，假设相似行为体之间的相互作用会减少它们之间的差异，而不同行为体之间的相互作用会增加它们之间的差异。我们的分析探讨了不同程度的容忍其他观点、对其他观点的反应、与不同观点的行为体接触、多个意识形态维度、经济自身利益和外部冲击对极化的影响。结果表明了一些防止或至少减缓极端极化发展的策略。
