UC San Diego

Why does the competitiveness of an election affect voter turnout? Previous research has focused on elite behavior in mobilizing political participation and voters' altered assessments about the importance of their vote. However, I argue that exposure to political competition activates voters' emotions---which in turn affect the decision to turnout---and that individual differences in threat sensitivity moderate this mediated relationship. After first elaborating a theory for these relationships, I use data from the 2008 National Election Study to demonstrate that heightened electoral competitiveness is associated with stronger emotional evaluations of the presidential candidates. To further elucidate the relationships, I collect a sample of 113 million status messages posted on the online social networking site Facebook during the 2008 presidential election. Automated content analysis reveals that users living in competitive "battleground" states are more likely to express emotion when they discuss politics on the site, and that emotional activation in status messages partially mediates the relationship between exposure to competition and self-reported voting. I next explore whether a genetic sensitivity to threat conditions the way that exposure to political contention affects voter turnout. The nascent genopolitics literature theorizes that genetic, psychological, and physiological differences should be integral in interpreting political stimuli from the environment, but there have been few empirical confirmations of this expectation. I find in two distinct datasets that people who carry a version of a gene that makes them especially sensitive to social stress are more responsive to the level of contention in their political environment. I follow up on this finding with a mobilization field experiment designed to activate emotions toward political competition. My dissertation is one of the first attempts to identify the specific causal mechanisms that underlie the effects of individual biological differences on political outcomes. This research topic is relevant and timely: as our country continues to polarize and the consequences of people's emotional reactions to political disagreement intensify, it is important to understand the causal mechanisms that relate political contention to political behavior