Precautionary Reasoning and Vaccination: An Empirical Test of the Precaution Rule

Background. Humans have cognitive abilities that enable them to decide about taking precautions, such as avoiding predators, detoxifying food, and possibly taking vaccinations. By hypothesis, these cognitive abilities include reasoning about and applying precaution rules, such as taking precautionary actions conditional upon being exposed to a hazard (i.e., perceived threat) and belief that the precautionary action protects against the hazard (i.e., coping appraisal). Whereas standard health psychology models typically treat the perceived threat and coping appraisal as two separate factors, the precaution rule entails that they should be treated in conjunction. In this study, we tested (i) whether people’s stated vaccination intentions are in line with reasoning according to the precaution rule, (ii) under which circumstances they reason according to the precaution rule, and (iii) how the perceived threat and coping appraisal are associated with individual differences in worldviews. Method. We used a cross-sectional survey (Study 1, N = 923–1,575) and a mixed-subject experiment (Study 2, N = 811) with respondents from the Netherlands. Results. While threat and coping appraisals were related to vaccination intentions, respondents did not reason according to the precaution rule, irrespective of the circumstances. The threat and coping appraisals were associated with participants’ worldviews and partially mediated the association between these worldviews and vaccination intentions. Conclusion. Vaccination intentions are related to appraisals about threat and coping, but people do not use these appraisals in the normative manner proposed by the precaution rule.