When we confront poorly informed arguments by partisans on the other side of the aisle (say, regarding vaccines and public health), we often suspect that those people are ignorant or, even worse, stupid. The remedy for both would appear to be facts and logic (complete with sock puppets if necessary). Think tanks, policy advocacy groups, and crusading academics spend a great deal of time and energy to change minds in exactly that fashion. And yet theory and practice demonstrates that minds are seldom changed.

A few years ago, Yale law professor Dan Kahan undertook a study using observational and experimental data to explain why the Left and Right disagreed about policy relevant facts. “Political polarization on empirical issues like these occurs not only despite the lack of any logical connection between the contending beliefs and the opposing values of those who espouse them. It also persists despite apparent scientific consensus on the answers to many of these disputed questions.”

Prof. Kahan was particularly interested in the degree to which people:

His findings?

First, the study presents both observational and experimental data inconsistent with the hypothesis that political conservatism is distinctively associated with closed-mindedness: conservatives did no better or worse than liberals on an objective measure of cognitive reflection; and more importantly, both demonstrated the same unconscious tendency to fit assessments of empirical evidence to their ideological predispositions. Second, the study suggests that this form of bias is not a consequence of over-reliance on heuristic or intuitive forms of reasoning; on the contrary, subjects who scored highest in cognitive reflection were the most likely to display ideologically motivated cognition. These findings corroborated the hypotheses of a third theory, which identifies ideologically motivated cognition as a form of information processing that promotes individuals’ interests in forming and maintaining beliefs that signify their loyalty to important affinity groups.

There are three important lessons here.

First, the conceit (often embraced by political Objectivists) that improving the ability of people to think logically will improve the quality of the political debate is dubious. Prof. Kahan finds no correlation between poor cognitive ability and the embrace of illogical policy arguments. That’s because “Ideologically motivated reasoning is in fact expressively rational at the individual level. Because it conveys individuals’ membership in and loyalty to groups on whom they depend for various forms of support, emotional, material, and otherwise.”

In fact, an increase in the public’s ability to think clearly could lead to a deterioration of opinion quality. The better our ability to think logically, the easier it would be for us to recognize when to engaged in ideologically motivated reasoning and how best to do it.

Second, the conceit (often embraced by a host of well-meaning reformers and policy crusaders) that a better educated public would produce “better” policy opinions is also dubious. Prof. Kahan finds that motivated reasoning is most pronounced in politically sophisticates. They use their greater political knowledge to resist ideologically incongruent evidence. Increasing public knowledge about this or that could again lead to a deterioration of opinion quality.

Third, decreasing ideological polarization is a necessary prerequisite for improving the quality of the policy debate.