Taking SIDEs: The Cognitive and Communicative Processes of Political Polarization

Abstract

The social identity model of deindividuation effects (SIDE) and the hyperpersonal model are used in this study to investigate how political discourse via computer-mediated communication (CMC) influences political polarization. The SIDE model explains how visual anonymity and social identity salience affect social influence and adherence to group norms. The hyperpersonal model explains how CMC can enhance interpersonal relationship outcomes relative to face-to-face communication. This study extends the SIDE model using the hyperpersonal model to better understand how visibility or visual anonymity, political group affiliation, and social identity salience during online discussions affect political polarization. Results of an online experiment showed that when discussing political issues, the political party identity of individuals in a dyad affected political polarization. Talking with an in-group political party member led participant attitudes to become more extreme and increased intergroup differentiation. The interaction effect between the party identity of interlocutors and visibility also affected intergroup differentiation such that when participants were visible to one another, intergroup differentiation was significantly higher for in-group political discussions relative to out-group political discussions. Intergroup differentiation was also significantly higher following visually anonymous out-group political discussions relative to visible out-group discussions. Finally, two message effects were observed. The use of positive emotion words and the use of words reflecting in-group connection were related to political polarization. Participants who used more positive emotion words expressed more extreme attitudes, and those who used more in-group connection words expressed more in-group attraction. The implications for the SIDE model, online political discourse, and political polarization are discussed.