It seems that giving consideration to the other sides’ point of view hurts—literally. In another study Mr Frimer asked people who had voted in the 2012 presidential election whether they were interested in hearing why voters had backed the other side. Over a third of Obama voters and more than half of Romney voters compared the experience of listening to the other side’s voters to having a tooth pulled. (Mr Frimer did a related study in Canada before the 2015 election, with similar results, suggesting the findings are not unique to the United States.)
A study in 2016 by Jonas Kaplan of the University of Southern California suggested that such responses are hard-wired in the brain. Mr Kaplan asked 40 liberal voters to get into fMRI scanners while they read various statements, including those that supported liberal political orthodoxy (abortion should be legal) and those that challenged it (ten times more people are murdered with kitchen knives each year than are killed by guns). The opinions that challenged liberal positions prompted a greater flow of blood to a part of the brain which is associated with basic beliefs and a sense of personal identity. If this is true, it is not surprising that, when challenged, people are reluctant to admit the other side might have a point.