According to American research, opponents of vaccines do not think like everyone else: they tend to be more negative than average.
- Anti-vaxxers often have a negative way of thinking
- In France 47% of people questioned in 2019 thought that vaccines are not safe
The World Health Organization placed anti-vaccines among the top ten threats to global health in January 2019. Refusing to get vaccinated can hamper the fight against certain diseases, or even cause some to resurface. Thus, the United States faced the return of measles in 2019, whereas it had been declared eradicated in 2000. According to the WHO, vaccination makes it possible to prevent between two and three million deaths each year in the world. How to convince people opposed to these vaccines? For researchers at Texas Tech University, we must first succeed in understanding them. In their worksthey find that anti-vaxxers tend to be more negative than average and overestimate the likelihood that certain dramatic events will occur.
A different way of processing information
In the medical journal Vaccinated, the two researchers, Mark LaCour and Tyler Davis explain that this tendency to imagine the worst is not always linked to vaccines. According to them, these people would have a different way of processing information. “It assumes that there would be cognitive or affective variables that influence anti-vaccines,” explains Tyler Davis. To reach these conclusions, the researchers first conducted a survey of 158 people. They asked them to estimate the mortality rate associated with certain events, such as a bite by an animal, cancer or even a flood. The people most opposed to vaccines obtained worse results than those who were more favorable to vaccination: that is to say, they attributed higher mortality to the events. They also tended to overestimate the frequency of very rare things.
An altered understanding of probability
The researchers then carried out a second survey, this time asking participants to also estimate the frequency of events considered positive or neutral: a concert by a star, a visit by the Pope to the United States or the fact of give birth to triplets. Anti-vaxxers always tended to overestimate the frequency of negative events, even though their estimates of the frequency of positive events were more or less accurate. “Anti-vaccines don’t have the best understanding of the likelihood of certain events occurring, analyzes Mark LaCour, they could be more easily influenced by anecdotal horror stories. For example, thinking that their child can make a epileptic seizure from a vaccine, which is extremely rare.” On the other hand, the study finds no link between level of education and adherence to anti-vaccine theories.
“It is possible that these people have an attention bias towards negative things and those associated with death, which makes them remember much more of this information in particular”, suggests Tyler Davis. According to him, anti-vaccines would tend to seek biased or non-representative information, in particular to confirm their ideas.
The French, largely suspicious of vaccines
In 2019, the Gallup polling institute conducted a study for the English NGO Wellcome on anti-vaccines. In total, more than 140,000 people, spread over more than 140 countries, responded to the survey. According to the results, France is the first anti-vaccine country: nearly 47% of those questioned believe that vaccines are not safe.
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