People’s actions towards a competitive outgroup can be motivated not only by their perceptions of the outgroup, but also by how they think the outgroup perceives the ingroup (i.e., meta-perceptions). Here we examine the prevalence, accuracy, and consequences of meta-perceptions among American political partisans. Using a representative sample (N = 1056) and a longitudinal convenience sample (N = 2707), we find that Democrats and Republicans equally dislike and dehumanize each other, but think that the levels of prejudice and dehumanization held by the outgroup party are approximately twice as strong as actually reported by a representative sample of Democrats and Republicans. Overestimations of negative meta-perceptions were consistent across samples, over time and between demographic subgroups, but were modulated by political ideology: more strongly liberal Democrats and more strongly conservative Republicans were particularly prone to exaggerate meta-perceptions. Finally, we show that meta-prejudice and meta-dehumanization are independently associated with desire for social distance from members of the outgroup party and support for policies that harm the country and flout democratic norms to favor the ingroup political party. This research demonstrates that partisan meta-perceptions are subject to a strong negativity bias, with Democrats and Republicans agreeing that the shadow of partisanship is much larger than it actually is, which fosters mutual intergroup hostility.

Two studies (one preregistered) of Americans (N = 2,200) drawn from a nationally representative panel show that both Democrats and Republicans personally value core democratic characteristics but severely underestimate opposing party members’ support for those same characteristics. In turn, the tendency to believe that political ingroup members value democratic characteristics more than political outgroup members is associated with support for anti-democratic practices. Results suggest biased and inaccurate intergroup “meta-perceptions”—beliefs about what others believe—may contribute to democratic erosion in the United States.