Testing Psychological Correlates of Ambiguity Aversion in the Context of COVID-19 Vaccination: Evidence for Motivated Reasoning and the Appraisal-Tendency Framework

Perceiving ambiguity—a specific type of uncertainty—can lead to ambiguity aversion. In the context of vaccination, ambiguity aversion can manifest as vaccine hesitancy. We tested various correlates of ambiguity aversion in the context of COVID-19 vaccination to better understand how and why ambiguity about COVID-19 vaccines is associated with COVID-19 vaccine hesitancy. Two studies regarding beliefs about COVID-19 were conducted among 330 college students in the US and 204 college students in Israel during March to June 2023. Participants completed a survey assessing perceived ambiguity about COVID-19 vaccines, COVID-19 risk perceptions (i.e., likelihood, severity, and worry), emotions about COVID-19 vaccines, vaccination intentions, and information seeking about vaccination. Overall, key findings include higher levels of anger among individuals who report higher perceived ambiguity about COVID-19 vaccination, as well as possible engagement in motivated reasoning processes when considering COVID-19 vaccination. More specifically, consistent with motivated reasoning, Americans who perceived higher ambiguity about COVID-19 vaccines reported lower worry about and lower perceived severity of COVID-19, which were each associated with lower vaccination intentions and lower information seeking about COVID-19 vaccines. In line with the Appraisal-Tendency Framework, Americans who perceived higher ambiguity about COVID-19 vaccines reported higher anger about COVID-19 vaccines, which was associated with lower perceived severity of COVID-19. Consistent with conceptualizing ambiguity as an aversive experience, Americans who perceived higher ambiguity about COVID-19 vaccines reported lower happiness about COVID-19 vaccines, which was associated with both lower worry about and lower perceived severity of COVID-19. These relationships were not present in the Israeli sample. Further, both Americans and Israelis who perceived higher ambiguity about COVID-19 vaccines reported lower feelings of relaxation from the COVID-19 vaccine, which was associated with lower perceived severity of COVID-19. These results can improve our understanding of processes involved in ambiguity aversion. Findings also provide greater insight into vaccine hesitancy and have practical implications for creating culturally appropriate vaccine health communications and interventions that consider the phenomenon of ambiguity aversion. Indeed, if motivated reasoning does play a role in responses to ambiguity, incorporating strategies to reduce motivated reasoning may contribute to vaccine uptake.