Virtually no one goes through life thinking, “My beliefs about the world are driven by irrationality and heuristics.”
No, we all fancy ourselves to be rational.
Regardless of what we believe, we believe the evidence is on our side.
Take John and I, for example.
John is certain that the measles, mumps, and rubella vaccination causes autism. But I believe John is wrong. I have evidence that John is wrong: if you look at the people in a population who are diagnosed with autism, there is no statistical difference between those who received vaccinations as children and those who did not. Epidemiologically, there is nothing that connects vaccinations to autism. (i.e. Taylor et. al 1999, etc.)
What is correlated with parents not vaccinating their children? Well, outbreaks of measles, for one. (CDC)
But my evidence is meaningless to John. Why? He believes different evidence. John’s evidence might be anecdotal (à la Jenny McCarthy), or intuitive (he’s got a hunch), ideological (don’t interfere with ‘nature’), conspiratorial (it’s all a government cover up), or unfortunately widespread misinformation (as per Andrew Wakefield). Whatever the case, John does not think to himself, My beliefs about vaccinations are irrational. No, he’s got his reasons. And he is convinced by them.
He is committed to his evidence as much as I am to mine.
As far as I can tell, given the data and evidence as I see it, John’s refusal to vaccinate his child is both irrational and irresponsible. But according to John’s evidence, he believes he is making the best decision for his child. He believes it dearly.
John and I both have our evidence, and this is the problem. Scientific, peer-reviewed, data-driven evidence is clearly only one kind of evidence — and it is a kind of evidence that John out-rightly rejects. John is so convinced by his reasons — whatever they are — that it doesn’t matter what I think.
Therefore, it is pointless for John and I to debate vaccinations. I think he is ignoring basic science. He suspects that I am deluded by blind trust in the scientific establishment. We are at an impasse. It does not matter how emphatically I drone on about ‘evidence-based medicine’, falsifiable propositions, and the null hypothesis. John is having none of it. All of this is important to me, but not to him.
John is no sooner going to entertain the validity of my evidence than I am going to accept the validity of his. I seek to surrender my intuitions to the probabilities of empirical observation, and I strive to change my position as new data emerges (especially at such a large scale of consensus). Let’s be honest: John is probably not going to talk me out of these methodological convictions. “That’s what you believe is true,” he acknowledges. “But that is not what I think and feel about the issue.”
If I am going to convince John to vaccinate his child, I need to either help him change his functional definition of evidence itself or present an appealing counter-narrative in his language — a story told in his current ‘category’ of ‘evidence.’
Herein lies the dilemma of health promotion: ‘evidence-based research’ alone has never changed the minds or behaviours of people (or policy-makers) not already convinced of the validity of quantitative data.
Before John and I can have a meaningful conversation about vaccinations, we need to have a meaningful conversation about the nature of falsifiable propositions. And this needs to be a conversation, not a monologue correcting the ‘errors’ of his evidence. I cannot change John’s convictions and conceptualizations about the nature of evidence any more than I can change his deepest hopes and dreams.
I now view the anti-vaccine movement as a sort of cult, where any sort of questioning gets you kicked out, your crunchy card revoked. I was even told I couldn’t call myself a natural mother anymore, because vaccines are too unnatural. That’s fine. I just want to be the best parent I know how to be, and that means always being open to new information and admitting when I’m wrong. (Leaving the Anti-Vaccine Movement by Megan Sandlin)
This is the bottom line: I cannot change John’s mind. Only John can change John’s mind. If I accept this premise at the outset of our conversation, my interaction with John will be markedly different than if I were to presume myself capable of correcting John’s thinking for him.
After all, I am just like John: if you are going to convince me that vaccinations cause autism, you will have to show me evidence that I accept as valid — the kind of evidence I already use and trust to make sense of the world I live in.
John and I are so different. John and I are exactly the same.