Since the 1950s, political scientists have hypothesized that political polarization – an increased number of “political supporters” who view the world with ideological bias – is associated with an inability to tolerate uncertainty and a need for have predictable beliefs about the world.
But little is known about the biological mechanisms by which these biased perceptions arise.
To investigate this question, scientists at Brown University measured and compared the brain activity of committed supporters (liberals and conservatives) as they watched real political debates and news broadcasts. In a recent study, they found that polarization was indeed exacerbated by intolerance of uncertainty: liberals with this trait tended to be more liberal in their view of political events, conservatives with this trait had tend to be more conservative.
Yet the same neural mechanisms were at work, pushing supporters into their different ideological camps.
“This is the first research we know of that has linked intolerance to uncertainty to political polarization on both sides of the aisle,” said study co-author Oriel FeldmanHall, assistant science professor cognitive, linguistic and psychological to Brown. “So it doesn’t matter whether a person in 2016 is a strongly committed Trump supporter or a strongly committed Clinton supporter. What matters is that an aversion to uncertainty only exacerbates how two conservative brains or two liberal brains react the same when consuming political content. “
Jeroen van Baar, co-author of the study and former postdoctoral researcher at Brown, said the findings are important because they show that factors other than political beliefs themselves can influence the ideological biases of individuals.
“We found that polarized perception – ideologically distorted perceptions of the same reality – was strongest among people with the lowest tolerance for uncertainty in general,” said van Baar, who is now a research associate at Trimbos. , The Netherlands Institute of Mental Health. and drug addiction. “This shows that part of the animosity and misunderstandings we see in society is not due to irreconcilable differences in political beliefs, but rather depends on surprising – and potentially resolved – factors such as uncertainty. that people experience in everyday life. “
The study was published online in the Proceedings of the National Academy of Sciences Thursday May 13.
To examine whether and how intolerance of uncertainty shapes the way political information is processed in the brain, the researchers recruited 22 committed liberals and 22 conservatives. They used fMRI technology to measure brain activity as participants watched three types of videos: a neutral-worded news segment on a politically charged topic, an inflammatory debate segment, and a non-political documentary.
After the viewing session, participants answered questions about their understanding and judgment of the videos and completed an in-depth investigation with five political questionnaires and three cognitive questionnaires designed to measure traits like intolerance of uncertainty.
“We used relatively new methods to determine whether a trait like uncertainty intolerance exacerbates polarization, and to examine whether individual differences in brain activity patterns synchronize with other individuals who share the same. beliefs, ”FeldmanHall said.
When the researchers analyzed participants’ brain activity while processing the videos, they found that neural responses diverged between liberals and conservatives, reflecting differences in the subjective interpretation of the images. People who strongly identified as liberal treated political content the same and at the same time – what researchers call neural synchronization. Likewise, the brains of those who identified as conservatives were also in sync when processing political content.
“If you’re a politically polarized person, your brain syncs with like-minded individuals in your party to perceive political news the same way,” FeldmanHall said.
This polarized perception was exacerbated by the personality trait of intolerance of uncertainty. Participants – of all ideologies – who were less tolerant of uncertainty in everyday life (as indicated in their survey responses) had more ideologically polarized brain responses than those who are better able to tolerate uncertainty.
“This suggests that uncertainty aversion governs how the brain processes political information to form black-and-white interpretations of inflammatory political content,” the researchers wrote in the study.
Interestingly, the researchers did not observe the polarized perception effect during an apolitical video or even an abortion video presented in a neutral, non-partisan tone.
“This is essential because it implies that ‘liberal and conservative brains’ are not simply different in a stable way, like brain structure or basic functioning, as other researchers have argued, but that the differences ideological processes in the brain result from exposure to polarizing material, “said van Baar.” This suggests that political supporters may be able to come to an agreement – provided we find the right way to communicate.
Another author of the study was David J. Halpern of New York University and the University of Pennsylvania.
The research was funded by a start-up grant from Brown University and the COBRE grant P20GM103645 from the National Institutes of Health.