Preventing extreme polarization of political attitudes

Abstract

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, Polarization: What Everyone Needs to Know, 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.

The dynamics of political polarization

“…They show that small polarization differences in public opinion can influence selfreinforcement of relevant attitudes among the elites, that tipping points can occur at which polarization speeds up, and that Republicans seem to have already passed the critical threshold while Democrats are approaching it. Such tipping points also occur elsewhere in this volume, for example in the paper of Axelrod et al already discussed (6), and in Macy et al (9), which also focuses on political elites.…”

“…Macy et al ( 9) develop an agent-based model of polarization, focusing on a phase analysis of elite opinion. Their model of opinion dynamics, following from that of Axelrod's 1997 paper (12) and Axelrod et al in the current volume (6), shows that tipping points can emerge and, even in the face of significant external threats, prevent any return to an earlier equilibrium. Agents following rules of positive and negative influence and homophily interact to produce different levels of polarization.…”

“…Axelrod et al (6) set the stage by highlighting the threats that polarization presents to democracies, and ask via an agentbased model whether the dynamics of polarization can reach a threshold level at which it becomes a runaway process, and whether interventions can stem the tide. Their model is based on the assumption that interactions between similar actors will reduce their differences, and that the opposite is true for interactions between dissimilar actors.…”

“…Each model in the Special Feature makes specific assumptions, and then is set in motion to see how it evolves, thereby showing what can happen to polarization under varying circumstances. The Axelrod et al paper (6), for example, looks at how a number of different conditions shape the trajectory of polarization when guided by the standard attraction-repulsion model. Notably, they show that more attention to economic self-interest and less exposure to opposing views reduces the likelihood of extreme polarization trajectories.…”

“…Past a critical threshold, the polarization process can reach extremes and can become very asymmetric. Macy et al ( 9) also show how the political systems can be driven into extreme polarization and, like Axelrod et al (6), find that even large common shocks-such as a pandemic, economic collapse, attack by a foreign adversary, or impending climate catastrophe-are often unable to stop the dynamics of accelerating polarization.…”