A Social Norms Approach Intervention to Address Misperceptions of Anti-Vaccine Conspiracy Beliefs amongst UK Parents

"Given the potential dangers of anti-vaccine conspiracy beliefs for health-protective behaviours (e.g., vaccine uptake), an intervention to address conspiracy beliefs has been long-awaited."

Anti-vaccine conspiracy beliefs can reduce vaccination intentions. Parents' beliefs in anti-vaccine conspiracy theories are also related to their perceptions of other parents' conspiracy beliefs. Further, research has shown that parents hold misperceptions of anti-vaccine conspiracy belief norms: United Kingdom (UK) parents over-estimate the anti-vaccine conspiracy beliefs of other parents. This study tested the effectiveness of a brief online Social Norms Approach (SNA) intervention that corrects misperceptions using normative feedback to reduce UK parents' anti-vaccine conspiracy beliefs and increase their intentions to vaccinate their children.

As outlined here, social norms are informal, unwritten expectations about appropriate social behaviour, outlining what is acceptable and not in particular contexts. Two types of social norms are commonly implicated in health behaviours: injunctive norms, which refer to one's perception of what others approve or disapprove, and descriptive norms, which refer to one's perception of how prevalent an attitude or behaviour is. Social norms are important determinants of attitudes and behaviours.

The SNA begins with the premise that individuals are influenced by the beliefs and behaviours of others and often make misperceptions about how much others engage in certain behaviours. A consequence of such social norm misperceptions is the potential engagement in unhealthy behaviours due to a false belief that such behaviours are commonplace amongst peers. The SNA works by challenging these misperceptions of the belief and behaviours of others, reducing the perceived social pressure to engage in a problem behaviour. SNA interventions are often delivered online using computerised normative feedback to explicitly compare a) personal beliefs and behaviours to b) the perceived norms of peers and to c) the actual norms of a certain belief or behaviour.

The first phase of the study was baseline assessment, followed immediately by the intervention (or control) and immediate post-test measures (August 2020), and finally the six-week follow up (September 2020). At baseline, 202 UK parents of young children reported their personal belief in anti-vaccine conspiracy theories (e.g., "misrepresentation of the efficacy of childhood vaccines is motivated by profit"), future intentions to vaccinate, and their perceptions of other UK parents' beliefs and intentions. Participants were then randomly assigned to a normative feedback condition (n = 89) or a control condition (n = 113). Those in the former group received an online SNA intervention that compared participants' personal anti-vaccine conspiracy beliefs and perceptions of other UK parents' beliefs with actual normative belief levels (taken as an average from previous research conducted by the authors into UK parents' belief in anti-vaccine conspiracy theories).

The study found that parents receiving the normative feedback showed significantly reduced personal belief in anti-vaccine conspiracy beliefs at immediate post-test. Changes in normative perceptions of anti-vaccine conspiracy beliefs mediated the effect of the intervention. The intervention did not directly increase vaccination intentions; however, mediation analysis showed that the normative feedback increased perceptions of other parents' vaccination intentions, which in turn increased personal vaccination intentions. No significant effects remained after a six-week follow-up.

The researchers suggest various avenues for future research. For instance, studies could investigate how long the effects of the intervention on reducing anti-vaccine conspiracy beliefs can hold. Neighbors et al. (2010) concluded that a personalised normative feedback intervention to reduce alcohol use in heavy-drinking college students was more successful when administered biannually as opposed to annually.  Furthermore, one of the reasons for the lack of effect of the intervention in increasing vaccination intentions could a ceiling effect: Participants' baseline intentions to vaccinate were very high. Therefore, future research could focus SNA interventions on participants who are hesitant about vaccines. Moreover, future investigation could focus on tailoring personalised feedback about participants' perceptions of anti-vaccine conspiracy beliefs and vaccination intentions.

In conclusion: "The versatility of the approach and ease of application suggests that an online SNA using normative feedback has the potential to be applied as a practical strategy to attenuate anti-vaccine conspiracy beliefs and their consequences. Moreover, this type of intervention could be suggested for new or expectant parents as a pre-emptive approach."