Aug 04 2015

Convincing Antivaxxers

A new study has been published in PNAS exploring methods for changing the attitudes of those who are anti-vaccine. The results differ from a previous study published last year in Pediatrics. Let’s explore their methods and results.

Both studies questioned subjects about their attitudes toward vaccines and their willingness to vaccinate their children. The Pediatrics study was web-based and recruited 1759 parents. They divided them into four groups:

(1) information explaining the lack of evidence that MMR causes autism from the Centers for Disease Control and Prevention; (2) textual information about the dangers of the diseases prevented by MMR from the Vaccine Information Statement; (3) images of children who have diseases prevented by the MMR vaccine; (4) a dramatic narrative about an infant who almost died of measles from a Centers for Disease Control and Prevention fact sheet; or to a control group.

The PNAS study was in person, but only recruited 315 subjects. They divided people into three groups: 1) given information debunking vaccine myths, 2) told about the risks of measles and shown graphic images, 3) control group given information unrelated to vaccines.

The Pediatrics study found that, for the strongest anti-vaccine views at baseline, none of the four groups were significantly affected in terms of their willingness to vaccinate. The groups warned about vaccine-preventable diseases and shown images of sick children changed their beliefs about vaccines somewhat, but this did not translate into a significant change in intent to vaccinate (again, for the strongest anti-vaccine subjects at baseline).

The PNAS study showed the same result for the group in which vaccine myths were countered with scientific information, but they found that the group given information about measles, for example, did increase their willingness to vaccinate. This last result may contradict the Pediatrics study (it depends on how comparable the groups were).

What does this mean?

Taken together the studies indicate that simply giving people scientific information that contradicts myths they already strongly hold is ineffective in changing their beliefs. Or, even if they do change their belief, they won’t change their behavior but just find another justification. This is consistent with results from other studies which found that giving people factual information that contradicts their strongly held beliefs actually causes some to dig in their heels and strengthen their now debunked belief.

This has been termed the “backfire effect.”  Most of the research has involved political views, and suggests that when someone holds a belief strongly with emotional conviction, facts alone are unlikely to change their mind. In fact, by challenging them you engage their defense mechanisms which strengthen their convictions.

People engage in a number of strategies in order to maintain their strongly held beliefs against the evidence. Collectively these strategies are called “motivated reasoning.” They include strategies such as calling into question the power of science itself, or the power of science to address the specific topic of their beliefs (the scientific impotence argument).

Engaging in conspiracy theories, of course, is the bread and butter of motivated reasoning. Conspiracies solve all problems – they can be used to dismiss all inconvenient evidence, and explain the absence of evidence, the apparent scientific consensus, the lack of mainstream media attention, and the absence of evidence for the conspiracy itself. It is also extremely easy to twist facts and behavior to make them seem sinister.

These are all powerful psychological phenomena, that overwhelm dry scientific facts. Keep in mind, however, that this only applies to emotionally held beliefs. If we don’t particularly care about a certain conclusion, or if the science fits our world view, then we are happy to listen to the science. (You only get credit for being scientific, however, when you accept the science that goes against your strongly held or ideological beliefs.)

The two studies disagree on the effects of fear in motivating parents to vaccinate their children. The Pediatrics study found that scientific information, images, and narratives were equally ineffective. The information seemed to give the parents in the study pause, but they still held onto their fears of vaccines and did not change their willingness to vaccinate. The PNAS study found that combining scientific information with images did have an effect.

Clearly more research is needed. It seems that context and venue are likely to have a significant effect. Perhaps subjects felt more pressure to conform to information when they were present in person, rather than online. We also don’t know how long the effect will last – does it fade after a couple of days? Finally we don’t know if any intervention will actually change vaccination rates out in the world. Right now we only have data from contrived study situations.

There is good reason to suspect, however, that countering fear with fear is likely to be more effective than countering fear with dry science. Of course this all depends on how strongly held the anti-vaccine beliefs are. For the most ardent vaccine deniers, I doubt anything with have a significant effect.

Where do we go from here?

The one thing that is clear from all of this scientific evidence is that humans as a species are rather pathetic on average. We are emotional creatures that, by default, can easily render ourselves immune to logic and facts whenever our emotions are at stake. It is hard not to feel that this is the source of endless mischief and sorrow for humanity. How do we fix it?

The ultimate solution, in my opinion, is to promote scientific skepticism. The skeptical outlook is to consciously remove oneself from any emotional investment in any particular belief. Instead we align our identity with the process of science, listening to facts, and following valid logic and sound arguments.

Part of this is being transparent and engaging intellectually with others. The critical analysis of others will keep us honest. We must be our own harshest skeptic, for if not others will expose any flaws in our process. We will then be under pressure to examine our methods and change our conclusions if necessary. Essentially being a skeptic and being part of a community of skeptics harnesses inherent human psychology toward being logical and scientific, rather than irrational and emotional.

As a skeptic my primary motivation is getting it right (not defending any particular position), and if I don’t I know that other skeptics will point out my error, and if I don’t properly engage with their criticism, or if I dig in my heels, I will lose credibility.

Further, it’s important to simply give people an internal desire to value the truth, honesty, transparency, and following a valid process. The desire, however, is just the beginning. We also need to spread the tools of critical thinking. It’s a lifelong journey, and it’s not easy. It takes constant vigilance and self-examination.

The more skeptical the world is, however, the better off we are. The less motivated reasoning and nonsense there will be in the world.

Making the public more skeptical and scientifically literate is changing the game, but it’s a generational struggle. Meanwhile, we still have to deal with important issues like public health. These studies suggest that we may need to use a variety of strategies, which include warning people about the dangers of vaccine preventable diseases.

There is an entirely different set of psychological studies, however, that suggest that the “scared straight” approach does not work at all. Any effects are short lived. Therefore the entire approach of both of these studies is flawed. They are considering scientific information vs using fear, but there is a third way.

Within health care and public health researchers are exploring that third way, which can be called social norming. This approach tries to motivate people to engage in more healthy behaviors by emphasizing that most people engage in these behavior – essentially using social pressure to change behavior. These techniques are proving more effective than the scared straight method.

With individuals, researches are exploring what is called motivated interviewing – asking questions so that individuals state their goals, then exploring how to achieve those goals. This engages people in a way that makes them feel self-empowered and self-motivated, and also provided some social pressure to appear consistent. You just said you wanted your children to be safe and healthy, so will you take a simple step to protect them from disease?

Social norming and motivated interviewing are still exploiting human psychology and you might think of this as manipulation. There is validity to this view, but you can also look at it this way: human psychology will be involved one way or the other, you might as well give information in a manner that engages human psychology constructively rather than counter-productively. With both methods you are never lying or giving false or misleading information. You are simply presenting it in a manner that is compatible, rather than in conflict with, the likely emotions of the target.

Conclusion

Changing attitudes and behavior is remarkably difficult. The naive assumption that most people will respond to scientific information has proven over and over to be false. People are different in this regard, but for most people they will respond to science when it does not conflict with their emotions, and they will deny science with motivated reasoning when it does conflict.

Don’t think of this as true-believers vs rationalists. We are all true-believers some of the time, and rationalists at other times.

The goal is to give people the tools and the motivation to be rational more of the time. Meanwhile, while trying to engage with the public over important issues like public health, we need to frame our information so that it will actually have a positive effect. To ignore human psychology while trying to change behavior is folly.

19 responses so far

19 Responses to “Convincing Antivaxxers”

  1. pdeboeron 04 Aug 2015 at 9:08 am

    Steve, is the lack of evidence that science education is changing minds part of the reason that the SGU has become much more active on facebook lately?

    My facebook stream is now flooded with casual skepticism that is very sharable. It doesn’t come across as a science lesson. Mostly, I see jokes and memes which are fun but also seem like earworms working their way into the social norm.

    I think Jimmy Kimmel’s bit on antivaxxers might have been one of the biggest blows to them too. It made science denial a faux-pas.

  2. edwardBeon 04 Aug 2015 at 10:10 am

    Are the comments not working? or is it just me?

  3. Bill Openthalton 04 Aug 2015 at 10:40 am

    Steven —

    The one thing that is clear from all of this scientific evidence is that humans as a species are rather pathetic on average. We are emotional creatures that, by default, can easily render ourselves immune to logic and facts whenever our emotions are at stake. It is hard not to feel that this is the source of endless mischief and sorrow for humanity.

    We’re no more or less pathetic than any other species, even though our brains aren’t pre-wired for logical thinking. As a matter of fact, it’s rather likely such an arrangement would be, evolutionary speaking, utterly disastrous given the fact our complete motivation is grounded in emotions. Without emotions being able to override “logical” considerations, humans would have been evolutionary failures.

    Emotions make life worth living — for better or worse. Emotions give us novels, and poems and music. Love is an emotion and so is hate, and both are utterly, totally and completely irrational. Emotions make us human more than our sometime rationality does.

  4. steve12on 04 Aug 2015 at 2:05 pm

    The conspiracy is always around the corner with these people, and I see no way of breaking them of it.

    They will

    1.engage in a surface level discussion of “facts”

    2. Upon losing, argue a particular flavor of ad hom (you only believe that because you’re a liberal,conservative, shill, environmentalist, atheist, etc)

    3 Then say that those are the arguments/facts that (Al Gore, the EU, Big Pharma, Monsanto, The Reptilians, W & Cheney) want you to believe.

    Rinse and repeat.

    I really don’t see any way of reaching them logically. Some sort of social pressure within their lifestyle circles is all that these types seem to respond to.

  5. Bill Openthalton 04 Aug 2015 at 5:15 pm

    steve12 —

    I really don’t see any way of reaching them logically. Some sort of social pressure within their lifestyle circles is all that these types seem to respond to.

    That is because theirs is not a logical argument, and the logical part of our brain is not really equipped to override gut feelings — as Jonathan Haidt points out, its more of a lawyer trying to find acceptable post-factum reasons for our behaviour.

    And because our rational intelligence isn’t involved in our motivations, I am not afraid of artificial intelligence, because without emotional/irrational motivations, even the most capable intelligence would just sit around doing nothing.

  6. steve12on 04 Aug 2015 at 5:29 pm

    “And because our rational intelligence isn’t involved in our motivations, I am not afraid of artificial intelligence, because without emotional/irrational motivations, even the most capable intelligence would just sit around doing nothing”

    That a really interesting point. Out emotional logical tug-o-war results from our cortex being slapped on top of our phylogenetically older lizard brain. You would never re-create that on purpose!

  7. Kawarthajonon 04 Aug 2015 at 10:22 pm

    “The one thing that is clear from all of this scientific evidence is that humans as a species are rather pathetic on average.”

    Wow. Ouch. That is a quote that is dying to be taken out of context. I’m sure this condescending and defeatist attitude will not help you win over any anti-vaxxers or change the minds of parents who are fearful of vaxxines.

    Plus, you’re falling in line with the rest of pathetic humanity by using emotional judgements – i.e. pathetic – not a particularly scientific word. Maybe you’re having just a bad day, but the advice you’ve always given on the SGU to change public opinion about these issues is to not blame people for not believing the scientific evidence, not to condescend, but to find ways to engage them.

    … and then later…

    “we need to frame our information so that it will actually have a positive effect”

    Well, that’s more like it. Maybe you can re-word the first sentence I quoted to be less emotional and to have a more positive impact. Just sayin’.

  8. Ori Vandewalleon 04 Aug 2015 at 10:43 pm

    I suspect Dr. Novella was attempting to be clever there–the root of pathetic is pathos after all.

  9. a stray caton 05 Aug 2015 at 6:31 am

    Great post as usual, but I’m also concerned about the “human as a species are rather pathetic on average” sentence. I agree with it personally, but the assumption it rests on (absolute rationality is the perfect ideal) is something most people would take issue with. Besides, it just sounds mean!

    @ Bill O
    “And because our rational intelligence isn’t involved in our motivations, I am not afraid of artificial intelligence, because without emotional/irrational motivations, even the most capable intelligence would just sit around doing nothing”

    I wonder about that. Sure, values have to start from somewhere irrational, but don’t you think an intelligence could be designed with some initial values/goals and be purely logical from there? Why have conflicting emotional/irrational motivations?

  10. Steven Novellaon 05 Aug 2015 at 6:32 am

    I am not being condescending because the statement applies to all of humanity, of which I am a part. The point is valid – we are ridiculous emotional creatures that will twist reality in blatant and childish ways in order to protect what we want to believe. We also refuse to see this behavior in ourselves while delighting in pointing it out in others.

    This is not about being condescending. It’s about knowing our nature and limitations so that we can work hard to transcend them.

  11. Johnnyon 05 Aug 2015 at 8:39 am

    Steve, I agree with everything you wrote in this blogpost. However, mustn’t scientific skepticism also be accompanied by some sort of moral philosophy? David Hume’s famous dictum (which for all I know is valid) is that reason is a slave of the passions. In modern words, that it is our emotions that make us want to achieve or do anything at all, and that we (hopefully) use rational methods to achieve it.

    Also, quite a lot of your listeners seem less convinced about the merits of the skeptic identity or the skeptic community:

    http://sguforums.com/index.php/topic,44454.0.html
    http://sguforums.com/index.php/topic,44612.0.html

  12. Newcoasteron 05 Aug 2015 at 12:59 pm

    I’m surprised in a way that the “dramatic narrative” wasn’t more effective at changing attitudes about vaccination. One of the common memes in skepticism is that the other side relies on personal stories and anecdotes, and how powerful they are, and that should be one of the tools skeptics use. Michael Shermer (and many others) have talked about humans being “story telling animals”

    So, interesting that when actually put to the test, that approach didn’t seem to work. It seems that once someone has a belief for emotional reasons, there is very little that can be done to budge them from that.

    Sigh.

  13. BillyJoe7on 05 Aug 2015 at 5:28 pm

    Johnny: “mustn’t scientific skepticism also be accompanied by some sort of moral philosophy”

    I prefer the word “ethics”. The word “morals” reminds me of rules and regulations, dogma and bibles. And there is a verbal form “to moralise”. More to the point, scientific scepticism should inform your ethics, rather than emotion.

  14. BillyJoe7on 05 Aug 2015 at 5:30 pm

    …and, yeah, trying to herd sceptics is like trying to herd cats.

  15. Bill Openthalton 06 Aug 2015 at 8:55 am

    a stray cat —

    I wonder about that. Sure, values have to start from somewhere irrational, but don’t you think an intelligence could be designed with some initial values/goals and be purely logical from there? Why have conflicting emotional/irrational motivations?

    You mean Asimov’s three laws of Robotics?

  16. Johnnyon 06 Aug 2015 at 2:32 pm

    BillyJoe7: I think that moral philosophy vs ethical philosophy a semanitc issue. The underlying issue is that values are necessary in the mix.

  17. Johnnyon 06 Aug 2015 at 4:15 pm

    BillyJoe7: Also the polls illustrate that for quite a lot of listeners (if the sample is reflective of them) certain conclusions are more important than the methods for reaching those conclusions.

  18. BillyJoe7on 07 Aug 2015 at 5:20 pm

    Yeah, semantics. The religious have morals based on their bibbles. The non religious have ethics based on science, logic, and reason.

  19. Neurobonkerson 10 Aug 2015 at 12:05 pm

    Great post, I completely agree that beating this problem is going to require a somewhat more nuanced approach. I think you might have overlooked a key flaw in the PNAS study, in that somewhat bizarrely, it didn’t actually directly evaluate intention to vaccinate. That doesn’t sound like an important factor at first glance, as you’d assume intention to vaccinate would correlate with general vaccine attitudes, but as the Pediatrics study proved, this isn’t necessarily the case.

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