Abstract for: Facing Common Threats in a Polarized Environment

When facing a common threat, conventional wisdom suggests that members of a society will be able to set aside their differences and work together towards a collective solution. However, that this axiom is universal has been disproven by the disjointed and highly polarized responses to COVID-19 and the threat of climate change in the United States. Previous research has suggested that conditions are unfavorable for collective response, citing high levels of affective polarization, i.e., partisan dislike of members of the other party, low information and subsequent overreliance on social learning, and divisive influence by political elites. We synthesize these concepts into a mathematical model of opinion dynamics and evaluate different scenarios under which feedback between affective and ideological polarization may evolve. In a scenario with a high degree of social learning and high initial polarization, a common threat can deepen existing division, even when inherent preferences are equal between two groups. When initial polarization is lower, groups can reach consensus on the common threat, and reducing reliance on social learning and increasing differences in inherent preferences yields reduced polarization on pre-existing issues. This study helps solve the puzzle of why common, existential threats like COVID-19 and climate change are not guaranteed to unite polarized groups and suggests potential high-leverage intervention points to facilitate collective problem-solving.