A Longitudinal Test of Political Self-Effects on Social Media

Abstract

ABSTRACT This registered report details a longitudinal experiment testing political self-effects – changes in issue-related attitudes and indicators of political self-concept – resulting from political expression on social media. We also tested whether such effects were due to the composition or release of political messages on social media over time. American adults (N = 576), logged on to a fictional social media platform and engaged with discussions involving one of two political issues at three time points over a week. We examined whether participants who wrote a comment about the issue publicly (on the social media platform) or privately (in a text box) experienced changes in their issue-related attitudes or political self-concepts (compared to a control condition). Overall, we did not find consistent main effects of message composition or release at individual timepoints. Instead, message composition sustained issue-related attitudes over time (vs. control). Interaction analyses found that among those with high baseline issue interest, expression (vs. control) led to decreased issue interest and importance over time. Among those high in baseline political interest, message release (vs. control) increased positive issue-related attitudes. We outline an agenda for studying political self-effects that addresses, a) their cumulative nature, b) conditional effects, and c) the challenge of endogeneity.