Psychology of the anti-vax movement

21 May 2019

Interview with 

Sander van der Linden, University of Cambridge


Cartoon of switch turning on a person's head


Rates of vaccination around the world have dropped. This has let diseases like measles make a comeback. In 2017, 110,000 people died from measles, most of them children, a 22% increase on 2016. And in the first three months of this year, there was a 300% increase on measles cases compared with the same period in 2018. But why are people turning away from vaccines, and what can we do to best convince them that vaccines are safe? Adam Murphy spoke to Sander van der Linden, from the University of Cambridge Department of Psychology, about where this distrust comes from.

Sander - Well, I think it's really complicated. I think with the vaccines there are several causes. Some are political, so people see it as a threat to their individual freedom. Some are based around religion and values that people carry on within their culture and religious circles. And sometimes people are just confused by misinformation that's being spread on the internet, often deliberately, that causes vaccine hesitancy.

I think it's useful to distinguish between people who are vaccine resistant, and you can think of this as being people who are high on the conspiracy spectrum and totally immune, so to speak, to the idea of vaccines; people who are hesitant about vaccines or are just on the fence and may have been misinformed; and people who are currently not receiving vaccinations but who might consider doing so. So I think it's useful to try to consider different audiences because it's a complex issue and people have very differing motivations to not get vaccinated or to not trust the medical community.

Adam - So there's going to be some people we’re really going to struggle to reach and others that we can convince more easily?

Sander - Exactly. If you think about, for example, how people become vaccine hesitant, there's a lot of misinformation on the internet and on social media. People hear about it in social circles, and so on and those are instances you might be able to correct and intervene. But when you talk about anti-vax communities, so communities that are isolated from the rest of society that are very difficult to penetrate with factual information or scientific information. Communities who have become so entrenched where they are only receiving information from opinion leaders, or religious leaders, or even cult leaders, even when you get the facts in they're not going to do much because people look around and they follow norms and they see what the norm is, and the norm is not to vaccinate. Research shows it’s physically painful for people to deviate from what the norm is, often, and so even when these people are acquainted with the facts there might not just be enough to convince people. So I think that this idea of anti-vaccine communities that are isolated and marginalised are a separate issue from the vaccine hesitancy as a result of misinformation.

Adam - Now with the media and with social media we see these views all the time, so are they really as widespread as they appear? How widespread are these views?

Sander - I think it's difficult to quantify. But vaccine hesitancy is on the rise in most countries and vaccination rates have dropped in Europe and elsewhere, and that is partly attributed to the vaccine hesitancy. We've seen some instances in the United States in New York and California where certainly misinformation has played an important role in fuelling this and to some extent it's deliberate.

During the presidential election in the United States there were Russian bots, this was called the Internet Research Agency, who were deliberately starting disinformation campaigns on vaccines so floating pro- and anti-vaccine information to try to get people confused on this very issue, and these were bots retweeting things on the internet. I think that does play a role in heightening this particular issue and when people are concerned, uncertain about a variety of things it's a good moment to try to drive a wedge between a lot of these issues. And not just vaccines but also other issues people are unsure about, GMOs and things that are related to science and mistrust and so on. So I do think it's on the rise and that's concerning.

Adam - So that makes it even more important to try and change people's minds but we don't want to do that and make things worse, so how do we debunk these myths effectively?

Sander - Yeah, use an interesting word there - debunk. So what we've been trying to do is find a new approach which we call prebunking. We know that debunking isn’t as effective, just because of the way the human memory works. When you’ve been exposed to a myth, that's what sticks in your memory and every time you try to debunk it, you repeat it and you correct it, but what people remember is the myth and they forget about the correction. It's very difficult to effectively debunk these sorts of issues. So we tried to essentially prebunk these things and surprisingly, or perhaps unsurprisingly, we followed a vaccination metaphor with the idea of prebunking, so it's called psychological inoculation, so it works the same way. You expose people to a weakened dose of the myth, of the misinformation. Not so strong that you persuade people, weak enough to not overwhelm your psychological immune system, but weak enough that it sounds ridiculous for people. And that you can allow people to build mental antibodies to the misinformation so that when they're actually exposed to it they're much more resistant to actually believing it. And we do this in a variety of settings, for example we've done this in the context of climate change.

We do it by exposing the techniques that underlie most misinformation including the vaccine, so things like conspiracies and polarisation. And what we do is we preemptively try to acquaint people in a controlled environment with the main techniques that are being used so that people learn about them, and when it actually happens people can hopefully spot the techniques that are being used and recognise misinformation when it's being deployed, and be less resistant to it. And we’ve tried to test that online through a game we've developed, a social impact game to help try to educate people and engage audiences and we found some positive results with that so far. So the idea is to prevent is better than cure and I think the same is true for misinformation. If you can get ahead of it that's better than trying to correct things after the fact.

Adam - Now when we talking about vaccines, we’re talking about children's health. It's a more emotive issue than, say, climate change, does that change how we have to approach these issues?

Sander - Well certainly. What we know from experiments is that if I tell you that vaccines are safe or if a doctor tells you that vaccines are safe, but then subsequently you come across a picture on the internet of a child, a doctored image of a child that’s suffering from a side-effect of vaccines, it totally trumps your sense of science and your belief in scientific consensus. So I think that is an extremely important factor to think about, is that emotions do play a very big role when people think about their children and putting their children at risk. And I think communicating ways that resonate with people, other than just cold facts, is what's needed here. When you talk to parents about vaccines, I think you also have to talk about safety in experiential terms for people and not just facts because otherwise one side is just relating cold facts to people and the other side is trying to appeal to people's emotions, and that is an unfair debate.

Adam - There's been some talk lately of making vaccines compulsory and undercutting this whole distrust issue, where do you stand on that? Do you think that's a good idea?

Sander - I think it's a really complex idea. I mean I'm a psychologist, not a politician of course, but what we do know is that when you start making people do things they don't necessarily want to do or consent to, it can actually backfire and decrease trust and marginalise people further. I understand there's an important balance here to try to protect people's lives and to save lives and to not let other groups of people put others at risk. But then there's also the very real risk of having people further entrenched in their beliefs, further marginalised in their communities and lower trust of government further because you're making people do things. So I think maybe one thing to think about is the best way of going about this and how to communicate this and how to get people on board within those communities that will approve these mandatory plans that are currently being discussed.


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