It’s rare that the mainstream media gets it right about vaccines and autism, and when they do I feel obligated to point it out. Such is the case with Sam Wang’s article The Autism Myth Lives On. It’s well worth reading, even though it’s a couple of months old. (How I missed it when it first appeared, I don’t know.) Wang even nails some of the reasons why this myth persists:
Although her [Jenny McCarthy's] concept of evidence is flawed, I don’t blame her. The error highlights how our brains are wired to think. Like the authors of the 1998 study, she concluded that two events happening around the same time must be linked. They used the principle that coincidence implies a causal link. But there was no coincidence for her son: He was born in 2002, after thimerosal was removed from vaccines.
The problem is compounded by “source amnesia,” in which people are prone to remember a statement without recalling where they heard it or whether the source was reliable. Presidential candidate John McCain might have fallen prey to source amnesia when he repeated the vaccine-autism myth last month. Recollection is more likely when the “fact” fits previously held views; parents might already dislike vaccinations based on their kids’ reaction to shots. But when it comes to a complex issue such as autism, such errors of reasoning hinder us from distinguishing real causes from coincidences.
Actually, I do blame McCarthy, because she’s been told time and time again where she’s wrong, but it doesn’t sink in. After a certain point, it’s not just normal human cognitive quirks anymore. It’s willful ignorance, or, as I like to call it, the arrogance of ignorance.