Re-examining the effect of inoculation messages on anti-vaccine conspiracy attitudes: A conceptual replication of Banas et al (2023)

This is the first study to attempt replication of Banas et al (2023) on inoculation messages. The original experiment demonstrated that inoculation messages could stimulate resistance to anti-vaccine conspiracy theories. However, a gap was identified in this study where exposing participants with inoculation scripts did not stimulate motivational threat, the key component that drives the attitude to defend specific beliefs. In this replication study, we also included conspiracy mentality as the moderator variable that might influence the strength of the association between inoculation scripts and anti-vaccine conspiracy theories. Findings from this study shows that logic-based and fact-based inoculation scripts were perceived differently by participants. Logic-based scripts were perceived as the script that exposed more evidence (fact) compared to fact-based and baseline scripts. Contrary to the original findings, the study failed to replicate the effect of inoculation treatments on anti-vaccine conspiracy attitudes. Instead, prior attitudes on anti-vaccine conspiracy theories, involvement and conspiracy mentality were shown as the significant predictors.