Publication Date




Embargo Period


Degree Type


Degree Name

Doctor of Philosophy (PHD)


Communication (Communication)

Date of Defense


First Committee Member

Cong Li

Second Committee Member

Tyler Harrison

Third Committee Member

Michael Beatty

Fourth Committee Member

Soyeon Ahn


The growing global health threat of vaccine hesitancy is believed to be fueled by anti-vaccine movements around the world. Overall, the strong presence of anti-vaccination groups on the Internet, particularly social media, are important for bringing attention and attracting people to the cause. Such platforms are an ideal medium for the dissemination of anti-vaccination ideas, which often entail the spread of false or “fake” news and information questioning vaccine efficacy and safety. As this epidemic of online fake news is causing major disruptions in vaccine programs around the world, the current study employed the Heuristic Systematic model (HSM) to elucidate the effect of certain “heuristic cues” on the credibility and the subsequent sharing of anti-vaccination fake news on social media. The study is a 3 (attitude: pro-vaccine vs. anti-vaccine vs. neutral towards vaccine) ? 3 (emotion: anger vs. fear vs. control) ? 2 (social endorsements: low vs. high) between-subjects factorial design (N = 656). It was found that pro-vaccine individuals found the fake news content to be less credible than neutral or anti-vaccine individuals. Further, fear for anti-vaccine individuals lead to higher credibility perceptions (compared to anger condition), and at the same, led them to report higher self-expression motivation to share fake news (compared to anger and control condition). Anger for neutral individuals lowered credibility perceptions (compared to neutral condition), however, led to higher self-expression motivation to share fake news (compared to fear condition). In these emotional conditions for neutral and anti-vaccine individuals, a high (compared to a low) number of Facebook “likes” led to increased status-seeking motivation to share the fake news. Finally, it was found that while anger and self-expression motivation do not have a significant effect on sharing intention, both fear and status-seeking motivation significantly increase the intention to share anti-vaccination fake news. Theoretical implications are discussed in light of motivated reasoning and social influence for main effects, while interaction effects are discussed in light of media effects on implicit and explicit attitudes. Practical implications are also discussed as possible improvements to current interventions aimed at curbing the fake news issue, such as those focusing on ‘information immunization’, fake news flagging, and media literacy.


fake news; news credibility; news sharing; social media; vaccines

Available for download on Saturday, November 20, 2021