Partisan Identity and Political Decision Making
Authors: Bankert Alexa 
Published: June 2020

Democracy depends upon citizens’ ability and motivation to make political decisions: the decision to turn out and vote, to protest, or simply to support or oppose certain policies. Political scientists have dedicated significant attention to the study of individual political decision-making. This type of research was primarily shaped by the rational choice paradigm, which assumes the individual acts as a rational agent and attempts to explain and predict political behavior by examining the costs and benefits associated with it. This approach, however, does not account for people’s decision to become politically active in the face of high costs and low returns. Whereas some researchers have tried to further develop rational choice theory by expanding its parameters, political psychologists have explored alternative avenues including genetics, neuroscience, and personality and social psychology. Social psychology in particular has gained recognition among political scientists as the concept of social identity has spread throughout the discipline.

Social identity theory focuses on the part of an individual’s self-concept that is derived from perceived membership in a social or political group. In the political realm, race, religion, and ethnicity, as well as ideology and partisanship, represent some of the most consequential identities for people’s political preferences. In particular, an abundance of research has shown partisanship to be one of the strongest predictors of political attitudes, turnout, and voting behavior. Notably—and breaking with some of the axioms of rational choice—this string of research demonstrates that partisanship is not necessarily grounded in ex-ante political preferences and carefully considered party platforms but instead drives people’s political attitudes and behaviors. From that vantage point, the social identity approach reverses the causal arrow that was originally posited by rational choice: Rather than being the outcome of stable political preferences, partisanship serves as their origin.

To explain this reversed causation, social identity researchers postulate that partisans utilize their group membership as an anchor to navigate the political word. Motivated by the desire to be good team players and advance the party’s status, partisans fall in line with their party, thereby aligning their political attitudes with the party’s platform. Using surveys and field experiments, political psychologists have provided convincing evidence for the validity of these psychological dynamics. Especially in the United States, partisan identity is a key factor in explaining mass political polarization and interparty hostility. Contrary to many expectations, however, the social identity approach’s utility goes beyond the United States’ two-party system and extends to European multiparty systems despite the substantial variations across political systems. In addition to its value for empirical political behavior research, Social identity theory also comes with heavy normative implications. If partisans blindly follow their party’s stances on crucial political decisions, how can one ensure accountability, increase citizens’ understanding of complex political issues, and encourage partisans to reach across the aisle and engage with their political rivals?