According to a recent study by Dan Kahan at Yale, even the brightest among us can get a math problem wrong if the right answer goes against our politics.

It turns out that both liberals and conservatives let political bias affect their calculations - and it appears to be unconscious. 

Think that being a math whiz can protect you from such mistakes? Think again. The better that the study participants were at math, the more likely they were to let their political beliefs skew their mathematical reasoning.

In the study, more than 1000 participants with predetermined political views had their mathematical reasoning ability tested. Then they were asked to solve a challenging math problem that interpreted the results of a (fake) scientific study. Some participants were told that the data determined the effectiveness of a skin rash cream. Other subjects were told that the data described the effectiveness of "a law banning private citizens from carrying concealed handguns in public."

The research showed that participants who were good at math were more likely to get the skin rash cream problem right. That part was predictable. 

But when subjects were told that this data determined whether crime in cities had decreased after a gun ban, the results were quite different: "subjects’ responses became politically polarized—and even less accurate—when the same data were presented as results from the study of a gun-control ban."

A significant percentage of liberals performed near-perfect math when the right answer was that the gun control law decreased crime. But their math took a dive when the correct answer was that crime increased. Likewise, while conservatives performed well when the right answer was that the gun ban didn’t work, a significant percentage of them failed the problem when the right answer was that the ban did work.

What are the implications of this revelation in our day-to-day lives? 

This is another verification of how powerful bias is on our perceptions of reality. It shows that no matter how intelligent we are, we are susceptible to bending our perception of reality to match our assumptions.

If bias affects our mathematical assessments, then transparency and checks and balances should be essential to all research, particularly when it informs decisions that affect our lives. It should matter to scientists, politicians, journalists, and every one of us as we consume the information that affects how we vote and live.


Study: Motivated Numeracy and Enlightened Self-Government Dan Kahan, Yale

Do Facts Matter Anymore in Public Policy? US News and World Report