Affective polarisation is the tendency for people to feel increasingly positively towards their own political group and increasingly negatively towards opposing political groups. It concerns emotional and social evaluations rather than simply differences in policy preferences. The concept is particularly associated with partisan identity and the distinction between in groups and out groups. A person can therefore be affectively polarised even if the policy distance between their preferred party and an opposing party is not exceptionally large.
Research commonly defines affective polarisation as the gap between positive feelings towards an in party and negative or less positive feelings towards out parties. It is described as a horizontal form of evaluation because it concerns citizens' feelings towards other political groups rather than simply citizens' assessments of political elites.
Affective polarisation differs from ideological polarisation because it measures social and emotional distance rather than policy distance. Ideological polarisation asks how far political positions are separated or how extreme they are, while affective polarisation asks how people feel about opposing political groups. The two can occur together, but they need not.
Citizens can disagree strongly about policy while maintaining respect and positive interpersonal relationships, or they can dislike opposing partisans even when the policy differences between their parties are relatively limited. This distinction has become important in political behaviour research because partisan identity can function as a social identity, producing evaluations of people based partly on their group membership rather than solely on their policy preferences.
Affective polarisation is often measured using questions that ask respondents to rate political parties or groups on feeling scales, warmth scales, favourability measures, trust measures, or related indicators. In a two party system, researchers can compare evaluations of a respondent's preferred party with evaluations of the opposing party. In multiparty systems, measurement is more complicated because individuals may like several parties, dislike several parties, have weak or multiple party identities, or position themselves outside the major partisan groups. European research has therefore highlighted methodological challenges in applying concepts developed in two party contexts to multiparty systems. Measurement choices can affect the apparent level and distribution of affective polarisation.
Contemporary research increasingly treats affective polarisation as multidimensional. One influential approach distinguishes othering, aversion, and moralisation. Othering concerns perceiving political identity as marking fundamental differences between groups. Aversion concerns negative feelings towards opposing partisans, including dislike or avoidance. Moralisation concerns treating one's own partisan identity as reflecting fundamental moral values, which can make political disagreement appear to involve questions of right and wrong rather than ordinary differences of preference. These dimensions can reinforce one another but are conceptually distinguishable. This broader approach shows why a single feeling thermometer cannot necessarily capture every psychological mechanism involved in affective polarisation.
Affective polarisation can affect relationships beyond explicitly political contexts. Research has associated strong partisan animosity with lower interpersonal trust and with social preferences concerning relationships, cooperation, and interaction with members of opposing partisan groups. Studies have also examined links between affective polarisation and political tolerance, including the willingness to permit disliked political groups to engage in contentious activities. Recent British research reports a strong association between affective partisan polarisation and partisan intolerance, illustrating that emotional hostility can have implications for everyday democratic tolerance. These findings do not mean that every affectively polarised person behaves intolerantly, but they demonstrate why researchers distinguish emotional partisan division from ordinary policy disagreement.
Affective polarisation can be influenced by political parties, elite rhetoric, campaign messages, media environments, partisan social identities, political sorting, and perceptions of opposing groups. Negative campaigning can increase attention to differences between groups, while partisan communication can reinforce narratives about the intentions or characteristics of opponents. Political sorting can also strengthen affective polarisation when multiple social identities become aligned with the same party divide. However, the strength and direction of these relationships differ between countries and political systems. Research therefore avoids assuming that mechanisms observed in the United States operate identically in European multiparty democracies or other political contexts.
Affective polarisation should not be equated with hatred, extremism, ideological radicalism, or political violence. A person can dislike another political party without supporting extreme policies or rejecting democratic institutions. Likewise, affective polarisation can occur among people whose ideological positions are relatively moderate. The term is analytical and concerns the structure of emotional evaluations between political groups. It should also not be confused with ordinary partisan preference. Supporting one party more than another is not necessarily evidence of affective polarisation; the concept generally concerns a meaningful difference between evaluations of one's own side and opposing sides, particularly when negative out group evaluations become pronounced.
Affective polarisation is politically important because democratic politics requires people with different political identities to coexist, deliberate, negotiate, and accept electoral outcomes. High affective polarisation can make compromise more socially difficult if opposing groups are perceived not merely as competitors but as fundamentally objectionable outsiders. Research has linked stronger affective polarisation with lower political trust, lower satisfaction with democracy, reduced interpersonal trust, and concerns about democratic norms, although the strength and causal direction of these relationships remain subjects of research. Affective polarisation should therefore be measured separately from ideological disagreement and interpreted according to the specific population, party system, period, and instrument used.
