Uncertainty and inoculation: Instilling resistance to anti-vaccination conspiracy propaganda

Abstract

ABSTRACT Employing inoculation theory as a theoretical framework, we conducted an independent-groups experiment (N = 150), comparing the effects of an inoculation treatment to a control condition and examining uncertainty as a mediator of inoculation effects. To test inoculation effectiveness, we used an excerpt from an anti-vaccination conspiracy film Vaxxed as a counterattitudinal attack message. The results indicated that inoculation roused motivational defenses to protect initial attitudes and, subsequently, was effective at conferring resistance to conspiracy propaganda. Furthermore, relative to the control condition, inoculation treatment decreased attitudinal uncertainty. Importantly, and as predicted, within the inoculation condition, attitudinal uncertainty emerged as a mediator of the resistance process: For inoculated participants, an increase in motivational threat to defend one’s attitudes fostered by the inoculation treatment reduced uncertainty, and attitudinal certainty, subsequently, facilitated resistance against the message advocated in the conspiracy film, damaging to public health. These results have theoretical implications for research on inoculation and offer practical import for attempts at mitigating conspiratorial ideation.