Political polar opposites may be more alike than they think

The brains of politically extreme individuals, whether left- or right-leaning, appear to respond to and process political information in surprisingly similar ways, according to research published in the Journal of Personality and Social Psychology. The paper is titled “Politically extreme individuals exhibit similar neural processing despite ideological differences.”

“Both extreme liberals and extreme conservatives consumed the same political content, and even though they held vastly different beliefs, their brains appeared to process the information in a very similar manner,” said Oriel FeldmanHall, Ph.D., a professor of cognitive and psychological sciences at Brown University and co-author of the study.

“In contrast, moderates showed much more diverse brain responses, suggesting that extremity—above and beyond ideology—drives this shared way of processing political information.”

FeldmanHall and her co-author, Daantje de Bruin, MS, a doctoral student at Brown University, used a combination of fMRI brain scans, skin conductance measures, and eye-tracking on 44 participants with varying political ideologies and levels of extremism, while the participants watched a politically charged video.

Researchers found extreme individuals—even when they held opposing ideologies—exhibited similar patterns of brain activity when consuming political content that participants with moderate political views did not. This synchronicity was strongest during segments of the video that featured more extreme language.

Individuals with more extreme views were also more physiologically aroused—measured via galvanic skin response—when exposed to political content. These bodily responses appeared to amplify neural synchronization, further suggesting that emotion and arousal help bind people to their political beliefs.

“Regardless of whether someone identified as extremely liberal or extremely conservative, their brain responded to political stimuli in similar ways,” said de Bruin.

“This suggests that it’s not just what you believe, but how strongly you believe it and how emotionally reactive you are that shapes your perception of political reality.”

The findings offer scientific support for the “horseshoe theory” of politics, which posits that extremists on both ends of the political spectrum may resemble each other more than they resemble moderates.

“Our findings suggest that individuals with extreme opposing views may be more alike than they realize. Recognizing this shared experience could foster greater empathy and reduce dehumanization across the political divide,” said FeldmanHall.

The researchers caution that the study, which used U.S.-based political content and self-reported ideology measures, may not generalize globally. Future research should explore cross-cultural perspectives and other forms of extremism beyond political ideology, they said.