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When It Comes To Vaccines, Science Can Run Into A Brick Wall


Public health officials in the United States are used to fighting diseases like AIDS, heart disease and cancer. Sometimes they have another enemy to fight: us, or at least our erroneous beliefs. Over the last decade, public health officials have tried to debunk a belief some parents have that vaccinating their children can lead to autism.

NPR social science correspondent Shankar Vedantam came by to talk about some research, suggesting that efforts to spread the word about scientific truths can actually backfire.

SHANKAR VEDANTAM, BYLINE: There's this new work Brendan Nyhan at Dartmouth College. And what's interesting about Nyhan, David, is that he's actually not a medical researcher, but a political scientist. And over the last several years, he's been studying why it's so hard to debunk political myths and conspiracy theories - so theories such as Barack Obama was not born in the United States, or that the 9/11 attacks were an inside job. And so now, along with his coauthors, Jason Reifler, Sean Richey and Gary Freed, Nyhan decided to take a look at the vaccine safety messages that public health officials often use. He found something very interesting.

BRENDAN NYHAN: It's much harder to change people's minds than we might have thought. Giving people corrected information is often ineffective with the people whose minds we'd like to change, and in some cases it actually can make the problem worse.

GREENE: So he's testing out, finding that people just won't change their minds about what they think they know in the public health realm. And what does he mean by this actually might make the problem worse when you try to spread a message?

VEDANTAM: Well, that's the disturbing part of the study, David. It sounds like it's not just the messages as designed, but that they might actually be counterproductive. So Nyhan and his colleagues have conducted a survey of more than 1,700 parents across the United States. They first evaluated the parents about their views on vaccine safety and then they provide the parents with the information about vaccine safety - specifically about the MMR vaccine - this is the vaccine that protects children against measles, mumps and rubella - and what they find is that the message is superficially effective. So parents who hear the message become more likely to think that the vaccine is safe. But - there's a very big but...

NYHAN: Unfortunately, giving people corrected information also made them less likely to say they would vaccinate a future child with MMR vaccine. And that effect was concentrated among those parents with the least favorable vaccine attitudes.

GREENE: Shankar, I'm struggling to make sense of this. I mean you have parents who are believing that the vaccines were safer and those parents are less likely to want to get their kids vaccinated?

VEDANTAM: Well, I think, David, what Nyhan seems to be finding is that when you're confronted by information that you don't like, at a certain level you accept that the information might be true, but it damages your sense of self-esteem. It damages something about your identity. And so what you do is you fight back against the new information. You try and martial other kinds of information that would counter the new information coming in. In the political realm, Nyhan is exploring the possibility that if you boost people's self-esteem before you give them this disconfirming information, it might help them take in the new information because they don't feel as threatened as they might have been otherwise.

GREENE: This is a matter of people not wanting to acknowledge that they may have been wrong about something for many years.

VEDANTAM: That's right. And also that if they were to acknowledge that they have been wrong, it might mean large changes in, not just their behavior, but their sense of who they are and their sense of identity.

GREENE: It's interesting. I mean, this really sounds like a difficult position for public health officials fighting somewhat of an impossible battle. But if it's a matter of improving people's self-esteem before they get information, I mean, are public health officials confident that they can find a specific way to do that?

VEDANTAM: Well, the idea that self-esteem might help in communicating these messages is something that has not yet been tested in the public health domain, David, so it would remain to be empirically validated. I think the big take-away from this study is that it's a really dangerous idea to trust our intuition about these public health messages. It's really important to test them to see whether they work, because our common sense about how effective these messages might be might actually turn out to be wrong.

GREENE: Shankar, it's always good to have you on the program. Thanks a lot.

VEDANTAM: Thanks so much, David.

GREENE: Shankar Vedantam regularly joins on the program to talk about social science research. And you can follow him on Twitter @Hidden Brain. While you're at it, you can follow this program @NPRgreene and @MORNING EDITION.


GREENE: You're listening to MORNING EDITION from NPR News. Transcript provided by NPR, Copyright NPR.

Shankar Vedantam is NPR's social science correspondent and the host of Hidden Brain. The focus of his reporting is on human behavior and the social sciences, and how research in those fields can get listeners to think about the news in unusual and interesting ways. Hidden Brain is among the most popular podcasts in the world, with over two million downloads per week. The Hidden Brain radio show is featured on some 250 public radio stations across the United States.