Thou Shalt Be Biased
June 19, 2011 Leave a comment
One roadblock to better public policy is that people tend to weigh evidence in a subjective manner. (Research suggests this due to some combination of motivational and cognitive factors.) A new study by Anthony Bastardi, Eric Uhlmann, and Lee Ross plays up the role of desire in the process. The authors discovered that our desires alone are enough to corrupt how we weigh evidence.
Evaluations of purported scientific evidence were shaped more by what participants desired to be true than by what they had initially believed to be true. Conflicted participants, who planned to use day care for their children but initially believed such care to be markedly inferior to home care, interpreted ambiguous scientific evidence in a manner congruent with their desire to believe that their plans would not be disadvantageous for their children. After they examined mixed scientific evidence, these conflicted participants shifted their beliefs and considered home care to be no better than day care. By contrast, after exposure to the same mixed evidence, unconflicted participants—those who shared the same initial belief in the superiority of home care and intended to use only home care when they became parents—maintained their strong initial belief.
Why does this matter? Because if you want to believe America has the best healthcare system in the world, a climate policy that won’t end the world, and an education system that will make us the first to discover new things about the world, your actions (i.e. votes) will be based on those beliefs in combination with scientific evidence rather than on the scientific evidence alone.