Does Attitudinal Inoculation Confer Resistance to Violent Extremist Propaganda? Assessing Mechanisms, Long-Term Effects, and the Advantage of Visuals

Previous research suggests that attitudinal inoculation can confer resistance to violent extremist propaganda. The present study aimed to strengthen and extend this rather scant evidence base. First, we conceptually replicated Braddock (2022) and investigated whether attitudinal inoculation reduces intentions to support a violent extremist group (VEG) by eliciting higher levels of anger and counter-arguing. Advancing the literature, we examined as well if the effect of attitudinal inoculation on violent extremist behavioural intentions lasted for up to 1 week and if message-relevant emotionally evocative visuals enhanced the influence of inoculation stimuli. We conducted a multi-phase longitudinal online experiment with two waves (N_wave1 = 498; N_wave2 = 399). Participants read the inoculation treatment (or control message) and were then exposed to the propaganda of a fictional VEG. Outcomes were measured immediately and again after 1 week. Partially supporting Braddock (2022), inoculated participants who were less strongly ideologically aligned with the VEG reported (compared to the control condition) lower violent extremist behavioural intentions. Inoculation had no impact on the behavioural tendencies of individuals who were strongly ideologically aligned with the VEG. Crucially, contesting Braddock (2022), inoculated participants felt less (not more) anger towards the violent extremist group. After 1 week, no direct effect of attitudinal inoculation on violent extremist behavioural intentions but an indirect effect mediated by counter-arguing was confirmed. The modality of the inoculation stimulus did not moderate its influence. In summary, attitudinal inoculation conferred resistance to violent extremist propaganda for a short period and for individuals who are perhaps less at risk of being persuaded by VEGs. Further research is needed to replicate the exploratory findings and to investigate the role of anger as well as means to boost the long-term influence of attitudinal inoculation treatments. Please refer to the Supplementary Material section to find this article's Community and Social Impact Statement.