Perceived similarity and its consequences: Political misperceptions and intergroup attitudes in the U.S.

How similar do American partisans believe they are to their political opposition? Do theyaccurately estimate these beliefs, and have these perceptions changed over time? What are theconsequences of believing in political similarity? This investigation explored these questionsboth cross-sectionally and longitudinally using data from a three nationally representativesamples and one large sample of U.S. partisans. We find that a substantial portion of the U.S.population perceives a high degree of similarity between political groups. These beliefs shiftedslightly between 2021 and 2024, and partisans showed modest inaccuracies in estimating them.Importantly, those who perceived greater similarity across party lines reported lessdehumanization, less justification of political violence, and more positive intergroup attitudesoverall. When examining perceptions of political violence and intergroup attitudes, partisansacross the spectrum believed their own group to be more prosocial than the opposition, withDemocrats showing a stronger ingroup bias. Taken together, these findings reveal subtle butmeaningful misperceptions in beliefs about similarity and violence, and underscore how thesebeliefs relate to broader patterns in intergroup attitudes across large, representative U.S. samples.