There is strong consensus among scientists that vaccines are safe and effective in combating the spread of disease. Why, then, does such a large segment of the public believe false claims of a link between vaccines and autism and hold “anti-vax” attitudes? Matthew Motta, Timothy Callaghan, and Steven Sylvester (2018) suggested that this is due in part to citizens’ attitudes toward medical experts. About a third of their 1535 respondents indicated that they believed they knew more about the causes of autism than do the medical and scientific experts – indicating a high level of the cognitive bias of “overconfidence.” Furthermore, the people who scored lowest on a test of knowledge about autism were the most overconfident about their knowledge and were most likely to oppose mandatory vaccination. Motta and colleagues found that in general overconfident participants were not distrustful of the experts, but instead tended to elevate the opinion of non-experts and the value of their role in developing vaccination policy.
Overconfidence and Anti-Vaccination Attitudes
Motta, M., Callaghan, T., & Sylvester, S. (2018). Knowing less but presuming more: Dunning-Kruger effects and the endorsement of anti-vaccine policy attitudes. Social Science & Medicine, 211, 274-281.
Cognitive biases OverconfidenceMedia Supplement
This brief video from the Washington Post provides an overview of the anti-vax movement (41 sec) This video from the PBS NOVA series , Vaccines – Calling the Shots, explores the science and social science behind the use and avoidance of vaccinations (53 min)