Exploring the correlation between conspiracy theories and vaccine intentions: Characteristics, dynamics, and strategies to generate resistance to it

Conspiracy theories are considered as one of the factors that influence vaccine propensity. Not only specific vaccine conspiracy theories, those who endorse conspiracy theories in general or having conspiracy mindsets, for instance: “The government agencies monitor all citizens” can influence vaccine evaluation. During the COVID-19 pandemic, conspiracy theories became a prominent issue, gaining a significant amount of attention from psychology and public health scholars. Numerous studies have demonstrated a significant association between conspiracy theories and vaccine hesitancy where increases in conspiracy theories correspond to higher levels of vaccine hesitancy. Why do conspiracy theories influence vaccine hesitancy? What possible factors might strengthen or weaken the correlation between variables? What are potential strategies to generate resistance to anti-vaccine conspiracy beliefs? This thesis will address these by testing specific hypotheses to explore the correlation between conspiracy theories and vaccine intentions, providing current evidence to understand the association between them. By relying on cross sectional and longitudinal data, four studies were conducted to provide evidence to explore the association between the study variables. The first study examined the confirmation bias hypotheses where anti-vaccine conspiracy beliefs were presumed as an expressive responding-an intention to accept misinformation to reinforce their pre-existing beliefs. This hypothesis suggests that those who endorse conspiracy theories may not genuinely believe in the conspiracy proposition. Unfortunately, study 1 failed to test this hypothesis due to non-significant effects of the experimental treatments. We continued to follow up this hypothesis in study 2 using the the data from the Trust in Scientists & Science-Related Populism (TISP) project initiated by Harvard University. Here, we tested the confirmation bias hypotheses from study 1 using non-experimental approaches and found that correlation between vaccine conspiracy beliefs and vaccine intentions was stronger in those who mistrust scientists. In study 3, we explored the correlation between conspiracy mentality and vaccine intentions with longitudinal panel data from the COVID-19 Psychological Research Consortium (C19PRC) project initiated by University of Sheffield, Ulster University, University College London, University of Liverpool and Royal Holloway University of London. This study extended the correlational analysis between conspiracy mentalities and vaccine intentions and found social events as the possible moderator where the correlation between conspiracy mentalities and vaccine intentions were stronger during the initial introduction of COVID-19 vaccines in December 2021. For the final study (study 4), we replicated Banas et al. (2023) to re-examine the effect of inoculation messages on anti-vaccine conspiracy attitudes. Although we failed to replicate the significant effect of the original study, this replication provided a valuable contribution for the inoculation theory.