Surprising as this may seem, our finding is consistent with a great deal of research on how people react to their beliefs being challenged. People frequently resist information that contradicts their views, such as corrective information— for example, by bringing to mind reasons to maintain their belief — and in some cases actually end up believing it more strongly as a result.

To find out if this pattern holds for vaccines, my colleagues Jason Reifler, Sean Richey, Gary Freed and I surveyed a nationally representative group of parents with children living at home in 2011, randomly assigning some to get scientific information debunking the vaccine-autism link or other pro-vaccine messages, and others to a control group.

The problem in this case wasn’t getting parents to believe the facts. Our results indicate that parents who saw the corrective information were less likely to believe in the vaccines-autism myth than those who didn’t. It seems that raising the topic may have instead prompted skeptical parents to think of other concerns or hesitations they have about vaccines to defend their views on the topic.

In addition, our results show that other types of messages used by public health agencies — information about disease risks, a dramatic narrative and images of sick children — were also ineffective.