Bias is a fact of human life. Bias is also the bane of science. Much of the scientific method is designed to constrain bias from spoiling truth seeking. Humans are fallible creatures who tend to believe what we want to be true. Bias accumulates very quickly when we become involved. And, the numbers of biases that science deals with is huge, from recall bias, to selection bias, to wishful thinking, to the clustering illusion, to the Texas sharpshooter fallacy, to funding bias.

The average scientist accepts that biases exist and spends much of his or her time attempting to minimize the effects of bias (theirs and others) on their work – failure to do so is often professional suicide. This is also true of researchers in autism. The vast majority of professional autism researchers have normal human biases (such as having an autistic child, or a desire for professional recognition, or a particular political belief like libertarianism), but none that significantly undermine the independence of their work because they are controlled for. Moreover, when their work is viewed collectively such that biases can be averaged, the effects of bias are diminished even more.

However, when you look at the public advocates for the ‘vaccines cause autism’ hypothesis, the biases become pretty apparent and pretty dominant, and are similar in effect to the funding bias. The funding bias holds that:

When a scientist (or the scientist’s employer) is hired by a firm with a financial interest in the outcome, the likelihood that the result of the study will be favorable to that firm is dramatically increased. This close correlation between the results desired by a study’s funders and those reported by researchers we now call the ‘funding effect’

Now, I am not saying that all the leaders of the vaccine in autism movement are paid by industry. However, a large percentage of them are tied to their pursuits through self interest. Some, like researchers Andrew Wakefield or Mark and David Geier, or reporters David Kirby or Dan Olmstead, have tied their professional careers, very successfully, to the vaccine hypothesis and are too far invested to go back (Olmstead for instance has called the autism / vaccine debate the biggest medical controversy of our time; so have Mark Blaxill and David Kirby – their bias is showing, their conclusions have been drawn). Others, like researchers Laura Hewitson and Jon Poling, have children with autism and a personal and financial (they are claimants in vaccine court for their children) stake in the outcome of the debate. Some, like Boyd Haley, have set up a lucrative practice treating autistic children with alternative therapies based on the vaccine hypothesis, which practice would dissolve if the vaccine hypothesis were abandoned. Many, like Kenneth Aitken and Marcel Kinsbourne, have received large amounts of funding from Plaintiff’s lawyers suing vaccine manufacturer’s under the theory that the vaccines caused their client’s autism. And, almost all of the ‘experts’ on vaccines in autism are associated with organizations that unabashedly have already concluded that autism is caused by vaccines, from Generation Rescue to SafeMinds to Thoughtful House.

Many individuals associated with the ‘vaccines cause autism’ movement are also trapped in their positions to some degree. When you associate yourself with a non-mainstream movement like this one, particularly one that is particularly visible, your ability, particularly as a scientist, to reintegrate into the mainstream is very limited. Memories are long. Grudges are held. This factor in all likelihood puts people into a position when backing down from their advocacy that autism is caused by vaccines is almost impossible. What are you going to do if you change your position that drastically? Who is going to fund your next grant request? If you spent several years bashing the pharmaceutical companies and the government, how are you going to get back into the good graces of the biggest research funders?