Exposure to misinformation on social media : the role of contextual factors beyond motivated reasoning

American democracy is built on the ideal that citizens are informed and that this knowledge allows them to participate as members of an engaged citizenry. The presence of misinformation presents a threat to that ideal, especially with the ability of false content to flow quickly across social media platforms. This dissertation explores effects of misinformation on American democracy, specifically how Americans believe information and how they distance themselves from political others in their online networks through their attitudes and actions. Despite the attention given to misinformation, little is known about how the features of social media itself may exacerbate or mitigate possible effects. This dissertation uses three novel experiments to test the role of motivated reasoning in the relationships between exposure and belief, affective polarization, and unfriending or blocking on social media. The results indicate that people are not universally swayed by misinformation and further, that motivated reasoning may not be the best theoretical framework for understanding misinformation as it exists on social media. Additionally, people do not polarize because of seeing misinformation nor do they sever ties with others after being exposed to a false story. Rather, contextual factors like partisanship, whether people turn to social media more for news, and weak likeminded social ties play more influential roles in misinformation effects. This dissertation emphasizes the features of social media and the who of misinformation consumers. There are distinct groups of people who might be slightly more susceptible to false information. Partisans, people who use social media for news, and weak social ties reveal a great deal about how misinformation is processed and its effects. Numbers of likes and shares on a social media post and the political leaning of false content reveal considerably less. I argue that understanding the identities and characteristics of individuals who are targeted recipients of false content can better help scholars and professionals combat misinformation. Identifying these groups of people for whom, or scenarios in which, misinformation effects might be stronger seems a much more achievable goal than attempts by social media to deplatform problematic accounts or selectively censor individual pieces of content.