Research has found that vaccine-promoting messages can elicit state reactance (i.e., negative emotions in response to a perceived threat to behavioral freedom), especially among individuals with high trait reactance (i.e., proneness to experiencing reactance). This can result in a lower willingness to accept vaccines. We investigated whether inoculation against reactance - that is, forewarning individuals about potentially experiencing reactance - can reduce the effects of trait reactance on vaccination willingness. Participants (N = 710) recruited through Facebook were randomly allocated to be either inoculated or not. They were then shown a message promoting a fictitious vaccine, which included either a low, medium, or high threat to freedom. Contrary to research on other health topics, inoculation was ineffective at reducing state reactance toward the vaccination message. Inoculation also did not mitigate the effects of trait reactance on vaccination willingness, and was even counterproductive in some cases. High-reactant individuals were less willing to get vaccinated than low-reactant ones, especially at high freedom threat. Conversely, high freedom threat resulted in increased vaccination willingness among low-reactant individuals. Further research is needed to understand why inoculation against reactance produces different results with vaccination, and to develop communication strategies that mitigate reactance to vaccination campaigns without compromising the positive effects of vaccine recommendations for low-reactant individuals.
Anti-science attitudes can be resilient to scientific evidence if they are rooted in psychological motives. One such motive is trait reactance, which refers to the need to react with opposition when one's freedom of choice has been threatened. In three studies, we investigated trait reactance as a psychological motivation to reject vaccination. In the longitudinal studies (n = 199; 293), we examined if trait reactance measured before the COVID-19 pandemic was related to people's willingness to get vaccinated against COVID-19 up to 2 years later during the pandemic. In the experimental study (n = 398), we tested whether trait reactance makes anti-vaccination attitudes more resistant to information and whether this resistance can be mitigated by framing the information to minimize the risk of triggering state reactance. The longitudinal studies showed that higher trait reactance before the COVID-19 pandemic was related to lower willingness to get vaccinated against COVID-19. Our experimental study indicated that highly reactant individuals' willingness to vaccinate was unaffected by the amount and framing of the information provided. Trait reactance has a strong and durable impact on vaccination willingness. This highlights the importance of considering the role of trait reactance in people's vaccination-related decision-making.
Individually tailored vaccine hesitancy interventions are considered auspicious for decreasing vaccine hesitancy. In two studies, we measured self-reported format preference for statistical vs. anecdotal information in vaccine hesitant individuals, and experimentally manipulated the format in which COVID-19 and influenza vaccine hesitancy interventions were presented (statistical vs. anecdotal). Regardless of whether people received interventions that were in line with their format preference, the interventions did not influence their vaccine attitudes or vaccination intentions. Instead, a stronger preference for anecdotal information was associated with perceiving the material in both the statistical and the anecdotal interventions as more frustrating, less relevant, and less helpful. However, even if the participants reacted negatively to both intervention formats, the reactions to the statistical interventions were consistently less negative. These results suggest that tailoring COVID-19 and influenza vaccine hesitancy interventions to suit people's format preference, might not be a viable tool for decreasing vaccine hesitancy. The results further imply that using statistics-only interventions with people who hold anti-vaccination attitudes may be a less risky choice than using only anecdotal testimonies.
COVID-19 , Influenza Vaccines , Influenza, Human , Humans , Self Report , Vaccination Hesitancy
