Throwing science at anti-vaxxers just makes them more hardline

Since the uptick in outbreaks of measles in the United States, those arguing for the right not to vaccinate their children have come under increasing scrutiny. There is no journal of “anti-vax psychology” reporting research on those who advocate what seems like a controversial, “anti-science” and dangerous position, but if there was we can take a good guess at what the research reported therein would say.

Look at other groups who hold beliefs at odds with conventional scientific thought. Climate skeptics, for example. You might think that climate skeptics would be likely to be more ignorant of science than those who accept the consensus that humans are causing a global increase in temperatures. But you’d be wrong. The individuals with the highest degree of scientific literacy are not those most concerned about climate change, they are the group which is most divided over the issue. The most scientifically literate are also some of the strongest climate skeptics.

A driver of this is a process psychologists have called “biased assimilation” — we all regard new information in the light of what we already believe. In line with this, one study showed that climate skeptics rated newspaper editorials supporting the reality of climate change as less persuasive and less reliable than non-skeptics. Some studies have even shown that people can react to information which is meant to persuade them out of their beliefs by becoming more hardline — the exact opposite of the persuasive intent.

For topics such as climate change or vaccine safety, this can mean that a little scientific education gives you more ways of disagreeing with new information that does not fit your existing beliefs. So we shouldn’t expect anti-vaxxers to be easily converted by throwing scientific facts about vaccination at them. They are likely to have their own interpretation of the facts.