I4I Study 1: Experimentally Evaluating the Impact of Fake News on SARS-CoV-2 Vaccine Intentions
Creators: name: Bronstein, Michael
Publisher: name: Open Science Framework
Year: 2022
Subjects: subject: Social and Behavioral Sciences
subject: Psychology
subject: FOS: Psychology

description: Widespread vaccine hesitancy (Daly et al., 2021) has delayed establishment of herd immunity (Thunström et al., 2020) during the SARS-CoV-2 pandemic, causing vaccine-preventable morbidity/mortality. While it is widely assumed that the “infodemic” of online health misinformation accompanying the present pandemic (Ghebreyesus, 2020) contributed to this public health crisis, few studies have evaluated this assumption using experimental or other methods capable of supporting strong causal inferences about whether, how, and to what extent particular types of misinformation (e.g., fake news) alter willingness to vaccinate against SARS-CoV-2. Quasi-experimental (Carrieri et al., 2019) and observational studies (Roozenbeek et al., 2020; ,Montagni et al., 2021) suggest that fake news discourages vaccination. One of the only experiments examining the impact of fake news on vaccine-related outcomes found that exposure to an anti-vaccine news story reduced SARS-CoV-2 vaccine intentions by 4.5% (p=.030) (Greene &amp; Murphy, 2021). This study measured vaccine intentions using a single item, potentially limiting sensitivity and explaining why the effect of fake news was not strong enough to survive correction for multiple comparisons (Bonferroni-corrected p=.12), leaving open the possibility of Type I error. Other limitations of this experiment included that it only exposed participants to one anti-vaccine news item (calling generalizability into question) and did not measure vaccine intentions after exposing participants to a vaccine-related real news item (thereby omitting a useful benchmark against which to compare the impact of fake news). The present study addresses these limitations by exposing participants to varying ratios of fake:real news and determining how exposure influences scores on a well-validated, multi-item measure of SARS-CoV-2 vaccine intentions. The present study also extends previous work by investigating the mechanism underlying the relation between exposure to fake news and SARS-CoV-2 vaccine intentions. Research on conspiracy theories points to Health Belief Model constructs as mechanisms likely to explain this relation. Several such constructs (perceived disease risk, perceived vaccine dangerousness) mediate the longitudinal relation between belief in SARS-CoV-2 conspiracy theories and vaccine intentions (Romer &amp; Jamieson, 2020). In experiments, perceived vaccine dangerousness mediates the effect of conspiracy theories on vaccine hesitancy (Jolley &amp; Douglas, 2014; Daniel Jolley &amp; Douglas, 2017). These studies provide strong reason to suspect that exposure to misinformation (fake news, conspiracy theories) reduces SARS-CoV-2 vaccine intentions via effects on Health Belief Model constructs. Finally, the present study builds on past research by examining whether reasoning biases discourage vaccination via their effects on belief in fake news and conspiracy theories. Dual-process theories of reasoning posit that humans rely on both intuitive (largely autonomous, not requiring memory) and analytic (reliant on memory, supports hypothetical thinking) reasoning systems (Evans &amp; Stanovich, 2013). Less analytic reasoning styles are reliably related to belief in fake news (Pennycook &amp; Rand, 2019a, 2019b). This correlation likely reflects a causal relation: manipulations designed to suppress analytic reasoning increase belief in fake news (Bago et al., 2019). Similarly, bias against analytic reasoning reliably correlates with belief in conspiracy theories (Barron et al., 2018; Sadeghiyeh et al., 2020), and experimentally encouraging analytic reasoning reduces belief in these theories (Swami et al., 2014). If less analytic reasoning styles cause endorsement of misinformation, and misinformation endorsement causes vaccine intentions, then less analytic reasoning should exert an indirect effect on vaccine intentions via belief in misinformation. With this literature in mind, the present study: 1) Experimentally evaluates the impact of SARS-CoV-2 vaccine-related fake news (vs. real news) on vaccine intentions 2) Examines whether fake news exposure increases perceived vaccine dangerousness, explaining why exposure reduces vaccine intentions 3) Uses causal discovery analysis to investigate whether constructs not manipulated in our experiment (ex: less analytic reasoning styles) might cause belief in fake news and lower vaccine intentions