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The Impenetrable Bulwark of Vaccination Lies

2014 March 3
by Eric Horowitz

America has a problem. Some people are spouting the lie that vaccines can cause autism and other people are believing them.

This has led to some unfortunate false-equivalence when the issue is discussed, and wouldn’t you know it, that false equivalence makes people less likely to believe the truth. Sometimes there’s no false equivalence; people who lie about vaccines are just handed a platform to broadcast their destructive beliefs.

Once people believe vaccines can cause autism, those beliefs may be very hard to change. For example, research (pdf) by Dartmouth’s Brendan Nyhan and the University of Exeter’s Jason Reifler has shown that information aimed at correcting false beliefs is often useless. They found that not only does corrective information fail to make people believe the truth on issues ranging from the war in Iraq to tax policy, but if the new information runs counter to an ideological belief there can be a “backfire effect” wherein people strengthen their incorrect belief.

So what about specific attempts to correct misperceptions about vaccines? A new study by Nyhan, Reifler, Sean Richey of Georgia State, and Gary Freed of the University Michigan paints a bleak picture.

In the study, which is set to be published in Pediatrics, 1759 parents with a child under the age of 18 were surveyed about their attitudes on vaccines. A few weeks later they were surveyed again, but this time participants were divided into a control group and four different treatment conditions.

Each treatment condition was aimed at improving perceptions of the risks and benefits of the measles-mumps-rubella (MMR) vaccine: There was 1) an “autism correction” condition, in which participants were presented with a CDC explanation debunking the link between vaccines an autism, 2) a “disease risk” condition, in which participants were told about the adverse consequences of having MMR, 3) a “disease narrative” condition, in which participants where presented with a mother’s account of her child’s hospitalization for measles, and 4) a “disease images” condition, in which participants were presented with pictures of a child who had one of the diseases. Participants in the control group were presented with additional information about bird feeding. After receiving one of the five types of additional information parents reported their attitudes about vaccine side effects and the likelihood that they would vaccinate a future child.

What Nyhan and his collaborators discovered is mostly bad news. While parents in the autism correction condition were less likely to agree with the statement “some vaccines cause autism in healthy children,” they did not have fewer concerns about MMR side effects and they were not more likely to vaccinate their child. In fact, parents in the autism correction condition with less-favorable attitudes toward vaccines (attitudes in the lower third of the sample) were less likely than other participants to say they would vaccinate their child in the future.

As for the other conditions, none of them increased the likelihood of vaccination either. The “disease narrative” condition even appeared to make parents more likely to believe that the MMR vaccine could have serious side effects.

The lesson is that, at best, throwing together an information-based plan to increase vaccinations probably won’t work, and at worst, it will be counterproductive. We tend to think about the necessity and risk-free nature of vaccinations as facts – that telling somebody vaccinations don’t cause autism is like telling them that the body needs oxygen. But evidence is building that attitudes about vaccinations may be more like an ideological belief. For some people, hearing that vaccines don’t cause autism is like hearing that tax cuts for the wealthy aren’t good for the economy. They’re probably not going to be convinced to change their mind in an afternoon.

The question then, is where do we go from here? At this point it feels like the only good answer is “the drawing board.”

Addendum: For a good example of the harmful false-equivalence described above take a look at NBC’s coverage of the study. Despite the fact that the study has nothing to do with the actual efficacy or side effects of vaccinations, the article quotes two anti-vaccine activists as saying that the study somehow vindicates their position, and it does this before quoting a single medical expert.

Here’s the most aggravating section:

“It is a big mistake for public health officials to assume that those resisting public health messaging about vaccines and diseases are ignorant, uneducated, ‘anti-science’ and that they lack social conscience,” said Barbara Loe Fisher, president of the National Vaccine Information Center and a frequent critic of vaccines.

Michael Belkin, 60, a Seattle vaccine critic whose infant daughter died in 1998 after recommended shots, said parents want to make up their own minds.

“People are skeptical about drug companies. Why should they not be skeptical about vaccines?” he said.

Actually, if you define “ignorant” and “uneducated” as “not believing true things are true,” those resisting public health messaging about vaccines are ignorant and uneducated. The fact that it’s hard to make these people change their minds does nothing to vindicate their position.

There’s been enough of a focus on false-equivalence in the media that you would think NBC would be more careful about it, especially when dealing with an issue like vaccination, where false-equivalence is much more harmful than in political domains. It’s truly a shame that NBC chose to re-litigate a faux-debate in a story about a study that doesn’t even profess to shed light on the facts relevant to the debate.
Nyhan, B., Reifler, J., Richey, S., & Freed, G.L. (2014). Effective Messages in Vaccine Promotion: A Randomized Trial Pediatrics

2 Responses leave one →
  1. Nathan permalink
    March 16, 2014

    Hmmm. This is really interesting research. I wonder if there would have been a different result if one condition was told that the majority of scientists didn’t believe vaccines cause autism. In effect, this would be influencing participants via an argument from authority instead of from fear.

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