The news about a resurgence of measles raises interesting questions about how we evaluate evidence. About a dozen years ago, a small study alarmed parents and caregivers that the measles vaccine may cause autism. Since then, several large-scale studies have debunked that theory, and the article was retracted.

But the damage was done—and it lingers. A few hold-outs still believe the vaccine may be dangerous, and so they do not have their children vaccinated.

Recently, about 100 measles cases have emerged in the U.S., and once again, the evidence is up for evaluation. How are people convinced? What makes people change their minds?

In his book Factfulness, Hans Rosling offers this advice:

[I]f you are skeptical about the measles vaccination, I ask you to do two things. First, make sure you know what it looks like when a child dies from measles. Most children who catch measles recover, but there is still no cure and even with the best modern medicine, one or two in every thousand will die of it. Second, ask yourself, “What kind of evidence would convince me to change my mind?” If the answer is “no evidence could ever change my mind about vaccination,” then you are putting yourself outside evidence-based rationality, outside the very critical thinking that first brought you to this point. In that case, to be consistent in your skepticism about science, next time you have an operation, please ask your surgeon not to bother washing her hands.

Along these lines, a Medium article, The Falsification Mindset, suggests ways for us to change our opinions. The author encourages us to consider what evidence we would need in order to change our minds. This process is particularly useful because we more typically look for reasons to continue believing what we believe—confirmation bias.

Image source.

Discussion:

• What examples can you identify of when you have experienced confirmation bias. In retrospect, could you have avoided the bias to make a better decision or to have a more accurate view?

• What’s your view of the measles vaccination? How did you form this opinion? How has it changed over time?

• Identify a belief. What evidence would you need to think differently?

• How is humility relevant to this situation?