By now you've likely heard that Andrew Wakefield, the British doctor whose 1998 paper published in The Lancet linked autism to the measles, mumps and rubella vaccine, has been found by that country's medical supervisory board to be guilty of "unethical" research, dishonesty, financial impropriety and "serious professional misconduct". And if you've been following the story you know that the paper has been partially retracted by The Lancet, disowned by most of Wakefield's co-authors and its findings have been refuted by subsequent and far more rigorous research. You might even know that the vaccine scare precipitated a sharp drop in vaccinations leading to a 20 fold increase in measles cases and at least 11 unnecessary deaths.
But what you might not know is that for an awful lot of people, none of it matters.
Despite the needless deaths, despite the revelation that Wakefield received $100,000 to conduct his test from lawyers hoping to sue vaccine makers and despite studies of millions of children who received the vaccine (as opposed to the 12 studied by Wakefield) showing no link to autism, as the verdict against Wakefield was read by the board's chairman he was "repeatedly heckled by distraught parents who support Wakefield..." And if you read the comments about the verdict at The Times you'll see that there are an awful lot of people who think that Wakefield is a victim of an elaborate plot to silence him orchestrated by the drug companies (out to make money) and the government (out to save money).
So what gives? One explanation is that our perception of risk is shaped largely our values. In a recent post at The Situationist you'll find a link to a video from the National Science Foundation in which Dan Kahan discusses the "cultural cognition thesis" - the idea that people perceive risk through the lens of their beliefs about what is and isn't good for society. By way of example he discusses the HPV vaccine Gardasil and the aversion to its administration by people who typically support vaccination. Apparently, for some at least, the perceived risk of green lighting sexual activity in young women outweighs the known risk of cervical and head and neck cancers.
What values then compel so many people to cling to the scientifically unsupported belief that vaccines cause autism? That profiting from preventing disease is morally wrong? That mandating vaccination of children is a violation of rights? Something else? Whatever the answer just remember that you won't ever change a juror's values; not in time for the verdict anyway. Instead, find a way to present the facts so that they fit, or at least do not conflict, with those values and if that's not possible then frame the issue so that some other, shared value decides the question.