International Society of Political Psychology

Conference Abstracts

The polarizing effect of partisan-ideological sorting

Lilliana Mason, Stony Brook University

Conference: ISPP 2011
Affiliation: Stony Brook University
Research Area: Electoral behavior and public opinion

Political scientists are deeply divided over whether political polarization is occurring at the mass level.  This debate has been limited by imprecise definitions and a lack of theoretical underpinnings.  In this paper I offer a clear definition of polarization and a theory-based explanation of the mechanism by which polarization has increased over the last few decades.  Specifically, I view polarization in terms of political behavior, not issue positions, and I believe that it has been increasing over the last 50 years as a result of partisan-ideological sorting.  This theory is informed by work in social psychology that makes concrete predictions about the psychological results of group membership.  Using this theoretical background, I argue that political identity is able to drive political participation, political bias, and political anger, even when issue positions are moderate.  Furthermore, and crucially, individuals can hold multiple political identities, and the more these identities overlap, the stronger the effects of identity on political behavior and anger.  The partisan-ideological sorting that has been observed to occur over the last 50 years has caused the nation as a whole to hold more overlapping political identities, which has strengthened partisan identity and the activism, bias and anger that result from strong identities.  I examine data from the American National Election Study and find that identity strength and identity overlap both explain a substantial amount of the year-to-year increase in polarized behavior above and beyond the effect of issue position extremity, and that the size of this effect changes over time.