People who believe Princess Diana was murdered or that John F Kennedy’s assassination was an elaborate plot are more likely to think that vaccines are unsafe, despite scientific evidence to the contrary, according to research published by the American Psychological Association.
“Vaccinations are one of society’s greatest achievements and one of the main reasons that people live about 30 years longer than a century ago,” said lead researcher Dr Matthew Hornsey, of the University of Queensland. “Therefore, it is fascinating to learn about why some people are so fearful of them.”
The study is the first to test the relationship between conspiracy beliefs and anti-vaccination attitudes among a global sample, according to Hornsey.
Hornsey and his co-authors surveyed 5,323 people from 24 countries on five continents using online questionnaires between 31 March and 11 May, 2016, measuring anti-vaccination attitudes and belief in four conspiracy theories: that Princess Diana was murdered; that the US government knew about the 9/11 attacks in advance and chose to let them happen; that a shadowy group of elites exist to plot a new world order; and that John F Kennedy was murdered as part of an elaborate plot.
Those with strong beliefs in conspiracies were most likely to hold anti-vaccination attitudes regardless of where they lived. For example, the more people believed that Princess Diana was murdered, the more negative attitudes they had about vaccinations.
In contrast, level of education had a very small impact on anti-vaccination attitudes. “People often develop attitudes through emotional and gut responses,” Hornsey said. “Simply repeating evidence makes little difference to those who have anti-vaccination attitudes.”
Large pharmaceutical companies, which profit from selling vaccines, are often targets for conspiracy theorists, said Hornsey. “For many conspiracy theorists, profits gained are a sign that the system is broken and the truth is being covered up by vested interests.”
“Trying to reduce people’s conspiracy beliefs is notoriously difficult,” Hornsey said. “An alternative possibility is to acknowledge the possibility of conspiracies, but to highlight how there are vested interests on the other side too; vested interests that are motivated to obscure the benefits of vaccination and to exaggerate their dangers.”
Anti-vaccination attitudes were also associated with intolerance of those who limit their freedom, disgust toward blood and needles and an individualistic worldview, according to the study.
Objective: Strengthening of antivaccination movements in recent decades has coincided with unprecedented increases in the incidence of some communicable diseases. Many intervention programs work from a deficit model of science communication, presuming that vaccination skeptics lack the ability to access or understand evidence. However, interventions focusing on evidence and the debunking of vaccine-related myths have proven to be either nonproductive or counterproductive. Working from a motivated reasoning perspective, we examine the psychological factors that might motivate people to reject scientific consensus around vaccination. To assist with international generalizability, we examine this question in 24 countries.
Methods: We sampled 5,323 participants in 24 countries, and measured their antivaccination attitudes. We also measured their belief in conspiracy theories, reactance (the tendency for people to have a low tolerance for impingements on their freedoms), disgust sensitivity toward blood and needles, and individualistic/hierarchical worldviews (i.e., people’s beliefs about how much control society should have over individuals, and whether hierarchies are desirable).
Results: In order of magnitude, antivaccination attitudes were highest among those who (a) were high in conspiratorial thinking, (b) 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.
Conclusions: These data help identify the “attitude roots” that may motivate and sustain vaccine skepticism. In so doing, they help shed light on why repetition of evidence can be nonproductive, and suggest communication solutions to that problem.
Matthew J Hornsey, Emily A Harris, Kelly S Fielding