The Election is Over, But Functional MRI Can Illuminate What Divides Us

November 4, 2020
Whitney J. Palmer

Certain parts of the brain respond differently to hot-button language found in campaign ads and speeches.

Americans have been voting for weeks leading up to yesterday's hotly contested Election Day. But, as the tabulations continue, questions still linger about what could be behind the deep political divide throughout the country. The answers could lie in functional MR brain scans.

In an effort to uncover what drives political leanings, researchers from a multi-institutional team recruited more than three dozen liberal-leaning and conservative-leaning participants and scanned their brains. They published their results in the Proceedings of the National Academy of Sciences.

Participants watched several videos relating to one of the most contentious issues from this election cycle – immigration, including the U.S.-Mexico border wall and the Deferred Action for Childhood Arrivals (DACA) program. Based on the scans, the team saw the brains of conservatives and liberals responded differently, and those differences were more pronounced when the videos included language that is frequently used in campaign ads.

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“Our study suggests that there is a neural basis to partisan biases,” said lead author Yuan Chang Leong, Ph.D., a post-doctoral scholar in cognitive neuroscience at the University of California, Berkley (UC Berkley). “In particular, the greatest differences in neural activity across ideology occurred when people heard messages that highlight threat, morality, and emotions.”

Investigators from UC Berkley, Stanford University, and Johns Hopkins University collaborated for this study and enrolled 38 young and middle-aged individuals who had similar socioeconomic and educational backgrounds. While these participants watched two dozen videos edited into 87 shorter segments, including news clips, campaign ads, and political speech snippets, that presented left- and right-leaning ideologies on immigration, the team conducted fMRI scans.

After each video, the viewers used a 1-to-5 point scale to rate their level of agreement, the team said.

Based on the team’s analysis, they determined that there was a high shared response in the auditory and visual cortices for both sides. But, that wasn’t the case in the dorsomedial prefrontal cortex where the brain processes word meanings. There, the most divisive neural responses came with words linked to risk, threat, morality, and emotion.

The tam also determined that the closer a study participant’s brain activity falls in line with the “average liberal” or “average conservative,” according to the study’s modeling, the more likely that person is, post-video, to adopt that political group’s position.

“This finding suggests that the more participants adopt the conservative interpretation of a video,” Leong said,” the more likely they are to be persuaded to take the conservative position, and vice versa.”

But, Leong’s team does not plan to stop there. They are also interested in examining whether neuroimaging can be used to develop more detailed and accurate models that can shed light on how people interpret political content. The goal, they said, is to strengthen interventions that bring the political parties together.