Plus, we explain the "backfire effect" that makes anti-vaxxers possible.
Six years ago, when being an anti-vaxxer was much cooler because their claims hadn’t been roundly debunked by the scientific community, SafeMinds funded a study to prove that vaccinations in babies caused autism. SafeMinds’ mission is “To end the autism epidemic by promoting environmental research and effective treatments.”
At the onset of the study, rhesus macaque infants were injected with vaccines and observed to look for any effects they had on their neurological development and social behavior. Scientists monitored the macaques’ interactions looking for “autistic-like” behaviors and, after years of sitting and staring at them, they didn’t find any. After the social observation period ended, the macaques were euthanized (which makes this story even more enraging). During the autopsy, scientists looked for evidence of smaller hippocampal cells, a common trait in people with autism, and found nothing. At the study’s conclusion, the scientists reported, “Our data do not support a role for thimerosal-containing vaccines in the neuropathology of autism spectrum disorder.”
After reviewing the data, SafeMinds responded, saying they have “Concerns about changes in the study design protocol and analysis that may have led to these contradictory results.” This rebuttal refers to a smaller-scale study that’s results encouraged them to fund this larger, more conclusive research in the first place. But when the study was replicated on a a larger scale, the scientists came to a different conclusion. And despite the fact that the scientists handed over of their data to be reviewed by an independent consultant, SafeMinds still wanted to see another analysis. “We feel that embedded within these data sets there are animals that have potentially an adverse reaction to this vaccine schedule that would mirror what happens in human infants.”
Why is it that time and time again when presented with contrary evidence, anti-vaxxers (as well as many groups that hold tightly to political and religious ideas that don’t mirror scientific reality) refuse to change their minds after seeing conclusive evidence? The answer can be found in the “backfire effect.” This proven widespread scientific reality posits that some people, when presented with factual information that contradicts their tightly-held beliefs, will will entrench themselves even deeper into the inaccurate position.