The current studies investigated the potential impact of anti-vaccine conspiracy beliefs, and exposure to anti-vaccine conspiracy theories, on vaccination intentions. In Study 1, British parents completed a questionnaire measuring beliefs in anti-vaccine conspiracy theories and the likelihood that they would have a fictitious child vaccinated. Results revealed a significant negative relationship between anti-vaccine conspiracy beliefs and vaccination intentions. This effect was mediated by the perceived dangers of vaccines, and feelings of powerlessness, disillusionment and mistrust in authorities. In Study 2, participants were exposed to information that either supported or refuted anti-vaccine conspiracy theories, or a control condition. Results revealed that participants who had been exposed to material supporting anti-vaccine conspiracy theories showed less intention to vaccinate than those in the anti-conspiracy condition or controls. This effect was mediated by the same variables as in Study 1. These findings point to the potentially detrimental consequences of anti-vaccine conspiracy theories, and highlight their potential role in shaping health-related behaviors.

Amid increased acts of violence against telecommunication engineers and property, this pre‐registered study ( N = 601 Britons) investigated the association between beliefs in 5G COVID‐19 conspiracy theories and the justification and willingness to use violence. Findings revealed that belief in 5G COVID‐19 conspiracy theories was positively correlated with state anger, which in turn, was associated with a greater justification of real‐life and hypothetical violence in response to an alleged link between 5G mobile technology and COVID‐19, alongside a greater intent to engage in similar behaviours in the future. Moreover, these associations were strongest for those highest in paranoia. Furthermore, we show that these patterns are not specific to 5G conspiratorial beliefs: General conspiracy mentality was positively associated with justification and willingness for general violence, an effect mediated by heightened state anger, especially for those most paranoid in the case of justification of violence. Such research provides novel evidence on why and when conspiracy beliefs may justify the use of violence.

This research experimentally examined the effects of exposure to intergroup conspiracy theories on prejudice and discrimination. Study 1 ( N = 166) demonstrated that exposure to conspiracy theories concerning immigrants to Britain from the European Union (vs. anti‐conspiracy material or a control) exacerbated prejudice towards this group. Study 2 ( N = 173) found the same effect in a different intergroup context – exposure to conspiracy theories about Jewish people (vs. anti‐conspiracy material or a control) increased prejudice towards this group and reduced participants’ willingness to vote for a Jewish political candidate. Finally, Study 3 ( N = 114) demonstrated that exposure to conspiracy theories about Jewish people not only increased prejudice towards this group but was indirectly associated with increased prejudice towards a number of secondary outgroups (e.g., Asians, Arabs, Americans, Irish, Australians). The current research suggests that conspiracy theories may have potentially damaging and widespread consequences for intergroup relations.