Agenda Setting through Social Media: The Importance of Incidental News Exposure and Social Filtering in the Digital Era

Conventional models of agenda setting hold that mainstream media influence the public agenda by leading audience attention, and perceived importance, to certain issues. However, increased selectivity and audience fragmentation in today’s digital media environment threaten the traditional agenda-setting power of the mass media. An important development to consider in light of this change is the growing use of social media for entertainment and information. This study investigates whether mainstream media can influence the public agenda when channeled through social media. By leveraging an original, longitudinal experiment, I test whether being exposed to political information through Facebook yields an agenda-setting effect by raising participants’ perceived importance of certain policy issues. Findings show that participants exposed to political information on Facebook exhibit increased levels of issue salience consistent with the issues shared compared with participants who were not shown political information; these effects are strongest among those with low political interest.