Affective polarization increases over time, but also as people age; age-related increases in affective polarization occur as a function of increases in partisan strength, and for Republicans, social sorting

Affective Polarization: Over Time, Through the Generations, and During the Lifespan. Joseph Phillips. Political Behavior, Mar 7 2022. https://link.springer.com/article/10.1007/s11109-022-09784-4

Abstract: The continual rise of affective polarization in the United States harms trust in democratic institutions. Scholars cite processes of ideological and social sorting of the partisan coalitions in the electorate as contributing to the rise of affective polarization, but how do these processes relate to one another? Most scholarship implicitly assumes period effects—that people change their feelings toward the parties uniformly and contemporaneously as they sort. However, it is also possible that sorting and affective polarization link with one another as a function of age or cohort effects. In this paper, I estimate age, period and cohort effects on affective polarization, partisan strength, and ideological sorting. I find that affective polarization increases over time, but also as people age. Age-related increases in affective polarization occur as a function of increases in partisan strength, and for Republicans, social sorting. Meanwhile, sorting only partially explains period effects. These effects combine such that each cohort enters the electorate more affectively polarized than the last.

Conclusion

The study of affective polarization has long recognized the weight of historical forces in shaping contemporary attitudes toward the opposing party. However, the way researchers have modeled these historical effects implicitly assume that partisans’ attitudes reflect the immediate political environment. This paper provides strong evidence that such an understanding is incomplete.

To be clear, there are strong period effects. Net of other considerations, affective polarization increases over time, and with important implications. People enter the electorate not as blank slates but as increasingly polarized products of their pre-adult environment. This increase is only slightly explained by over-time increases in ideological and social sorting in the electorate. Furthermore, least some of what we may have considered period effects are actually the result of aging-related increases in affective polarization. These aging effects, in turn, can be contextualized as increases in in-party warmth concomitant with increases in partisan strength over the lifespan.

These aging effects have important implications for the study of affective polarization. The finding that affective polarization changes throughout the lifespan suggests that interventions designed to reduce affective polarization may work among partisans in a variety of age groups. However, given their disproportionately high turnout rates (Leighley & Nagler, 2013) and increasing share of the population, making sure interventions to reduce affective polarization work among older partisans is crucial to reducing affective polarization in the American partisan population.

Sorting-based theories of affective polarization are meant to explain the rise of affective polarization among the electorate over time. However, the inclusion of individual-level measures of sorting, despite predicting individual-level affective polarization, largely fails to account for period effects among Democrats. This suggests that sorting-based theories of affective polarization need to be adjusted in scope. One possibility is that individual-level sorting does not explain aggregate patterns of affective polarization, but is still able to condition individual identity centrality and feelings towards partisan outgroups (Brewer & Pierce, 2005; Roccas & Brewer, 2002). Hence, sorting can still explain age-related changes in affective polarization among Republicans. This leaves aggregate-level features of the party system related to sorting (e.g. ideological polarization and demographic distinctiveness) as viable. Another possibility is that similar types of citizens (e.g. political sophisticates) are both well-sorted into parties and affectively polarized. Future work should tease apart these possibilities.

There are important limitations to this type of analysis. Intra-cohort trajectories are no substitute for intrapersonal variation. One cannot definitively conclude from this analysis that individuals are uniformly susceptible to age- and period-related changes in affective polarization, though individual-level panel data are consistent with what the APC models find. APC models can simulate the life span, but ultimately do so from aggregate data. Additionally, though mediation is useful to explain effects found in age-period-cohort analyses, mediation analyses using repeated cross-sectional data should be treated with caution. While reverse causality is not a threat to inferences (i.e. partisan strength cannot cause people to become 50 years old), one cannot make a definitive claim that that aging causes increases in affective polarization because it causes increases in partisan strength.

Despite these limitations, these analyses have important implications for understandings of affective polarization. Partisan prejudice is just as important to examine through the lens of the life-span as it is through history. Both are intertwined—age-related changes in attitudes occur contextually, through the social roles people inhabit, through the people they interact with, and through the historical events that unfold during their lives. Similarly, historical changes give shape to aggregate-level changes in the aggregate through affecting the attitudes of at least a subset of partisans. Future work would profit greatly from incorporating the lifespan in more nuanced ways, and with greater use of panel data.

Furthermore, despite a lack of robust cohort differences in affective polarization, aging and period effects have combined to produce a trend where citizens enter the electorate more and more affectively polarized over time. These results are consistent with Boxell et al. (2017), who, despite finding that younger cohorts are rising less quickly in affective polarization over time, find nonetheless younger people are more polarized than in the past. In other words, younger cohorts are experiencing higher levels of affective polarization in their impressionable years. Growing up in a more polarized landscape can leave an as-yet-unknown imprint on younger generations in the future such that cohort effects emerge in the future. This suggests that there is still a potential impressionable years effect with polarization among younger cohorts. These findings also suggest a need for studying political group attitudes in adolescence or earlier. National election studies only observe people over the voting age, but youth panels can be a powerful supplemental tool.

These results also draw attention to the often-overlooked role of age in public opinion beyond its use as a demographic covariate. Historically, isolating the role of age in public opinion has been difficult due to the difficulty of separating the effect of age from period and cohort. Nevertheless, it is important work. Changes in cognition and social role are widely-experienced, meaning their effects on political life are wide-ranging. Furthermore, estimating and explaining the effect of age can be done with more confidence than in the past. The social sciences have accumulated a number of high-quality repeated cross-sectional datasets that can leverage unprecedented temporal variation, which increases precision in estimates of period and cohort effects (Yang et al., 2004, 2008). Additionally, innovations in APC analysis continue to accumulate that researchers can leverage for more robust conclusions on the role of age in politics.