The Psychological Roots of Anti-Vaccination Attitudes: A 24-Nation Investigation

"In sum, the notion of attitude roots allows for a fresh perspective on what the barriers to vaccination uptake might be: away from beliefs and concerns, and toward the underlying factors that motivate those beliefs and concerns. However, there is only a small body of work that has examined the empirical case for whether these attitude roots are implicated in antivaccination attitudes"

Many programmes seeking to deal with vaccine refusals work from a model of science communication that assumes vaccination skeptics lack the ability to access or understand information/evidence. However, interventions focusing on the debunking of vaccine-related myths have proven to be either nonproductive or counterproductive, as these researchers explain. Using a data set of participants from 24 countries around the world, they examine the psychological factors that might motivate people to reject scientific consensus around vaccination and present implications for communicators.

As outlined in the paper, the low effectiveness of information campaigns that address vaccine hesitancy can be explained through the lens of motivated reasoning. "The principle of explication assumes that evidence drives attitudes. But increasingly researchers understand that the path also works the other way around: people develop an attitude - often through intuitions, emotions, and 'gut' responses that are difficult for them to articulate... - and are motivated to search for evidence to support their attitude....Weak, circumstantial or hearsay evidence is embraced to the extent that it reinforces the conclusion that one is motivated to reach. In contrast, scholarly evidence that is inconvenient or inconsistent with one's preferred conclusion can be discarded as corrupt, incorrect or irrelevant. Repeating evidence is not going to be effective for these people because it fails to address the underlying reason why they are processing the information in a biased way in the first place."

The "attitude roots" model of science rejection that is described in this paper seeks to elucidate these underlying motivations. The authors use a tree metaphor to explain this process. Above the surface - the leaves and branches in the metaphor - are the beliefs, myths, and concerns that people hold (e.g., about vaccination). It is these "surface attitudes" that people see and hear, and that are the targets of information campaigns and other such interventions described above. But according to the attitude roots model, it is what is underneath the surface that is most important: the underlying fears, identity issues, and worldviews that motivate people to embrace the surface attitudes. Four of the attitude roots discussed in that theory paper form the basis for this paper: conspiratorial beliefs, disgust sensitivity, reactance (skepticism of consensus views and intolerance of people telling someone how to think), and individualistic/hierarchical worldviews.

Data were collected between March 31 and May 11 2016 and were gleaned from a survey of 5,323 people in 24 countries. For each of the four criteria - belief in conspiracies, non-conformist behaviour, dislike of needles and blood, and individuality of thought - participants were asked to choose a response from a range between 1 to 5, where 1 meant "I strongly disagree" and 5 meant "I strongly agree". For example, individualism-communitarianism was measured with 17 items such as "The government interferes far too much in our everyday lives", and hierarchy-egalitarianism was measured with 13 items including "We have gone too far in pushing equal rights in this country". Sentences used to assess anti-vaccine attitudes included "Children get more vaccinations than are good for them" and "A vaccine might not prevent the disease". The researchers then correlated the degree of agreement with each statement and combined the four elements into a single scale in order to produce an average measure of attitude per citizen in each country.

In short, in order of magnitude, antivaccination attitudes were highest among those who (i) were high in conspiratorial thinking, (ii) were high in reactance, (c) reported high levels of disgust toward blood and needles, and (d) had strong individualistic/hierarchical worldviews. In contrast, demographic variables (including education) accounted for nonsignificant or trivial levels of variance.

The strongest antivaccination attitudes tended to be in Asia, and the weakest antivaccination attitudes tended to be in the West. Citizens of each of the four Latin American countries included in the survey (Argentina, Brazil, Chile, and Mexico) showed higher levels of belief in conspiracies and anti-vaccine attitudes than the average across the 24 nations surveyed. But the relationship between both these criteria turned out to be lower in Latin America than in other industrialised countries such as Canada, Germany, and New Zealand. "It is possible that this relationship could be stronger in 'rich' countries since they have better Internet access, and [that is where] conspiracy communities live and prosper," surmised Matthew Hornsey, lead author of the study.

In discussing the results, the authors note that the particularly strong role of conspiratorial beliefs that the study revealed can explain why corrective information and myth-busting about vaccinations has tended to be either ineffective or counterproductive. For most people, official health messages asserting a scientific consensus about vaccination are reassuring. But for those who have a conspiratorial worldview, these same official pronouncements that imply a lack of dissent can be inverted to be proof of a conspiracy. According to the attitude roots model, one should work with people's underlying worldviews: to acknowledge the possibility of conspiracies, but to show how vested interests can conspire to obscure the benefits of vaccination and to exaggerate the dangers. Similar methods might be possible for the other two predictors identified in this paper (the fourth predictor - individualistic/hierarchical worldviews - explained only a small amount of variance).

In short, creating change is possible when one identifies underlying motives for rejecting the science on immunisation, and then tailors interventions that are congenial to those underlying motivations (the so-called jiu jitsu approach). Given that no single message can canvass all of the possible underlying motivations for rejecting science, jiu jitsu persuasion relies on diverse messages delivered through multiple channels to appeal to different segments of the population.

On the question of communication strategy, they note that, although conspiratorial beliefs share a reliable and significant relationship with antivaccination attitudes across all 25 samples, inspection of Figure 1 shows that the effects in some cultures (particularly in Asia and South America) are modest in size. This suggests that conspiracy-related interventions may be less of a priority in these cultures than in the industrialised West. However, some of the relationships are relatively large: In Australia, Canada, Germany, New Zealand, United Kingdom, and the United States, knowing people's beliefs about conspiracies in general helps account for 17-27% of variance in antivaccination attitudes. This is a nontrivial amount of explanatory power.

In conclusion, these results suggest that understanding underlying motivations can open up new possibilities in terms of promoting more vaccination uptake - interventions that work in alignment with (rather than against) the effects of motivated reasoning on people's ability to embrace counterattitudinal information.