Politically extreme individuals exhibit similar neural processing despite ideological differences

The current state of political polarization in the United States encompasses a growing divide between partisans and a shift toward more extreme ideologies. Although rising ideological extremism poses societal challenges, the mechanisms supporting extreme views remain uncharacterized. Leveraging a combination of neurophysiological methods, we show that regardless of which side of the political aisle an individual is on, those with more extreme views show heightened neural activity to politically charged content in brain regions implicated in affective processing-including the amygdala, periaqueductal gray, and posterior superior temporal sulcus. Moreover, we observe that those who share an extreme perspective-even when they do not share an ideology-exhibit increased neural synchronization in the broader posterior superior temporal sulcus region while consuming political content. For those on the most extreme ends of the ideological spectrum, this effect is further influenced by listening to extreme language. Finally, we find that shared arousal, measured through galvanic skin conductance responses, modulates the strength of coupling between shared extremity and neural synchrony. Together, our findings suggest a role for affect in shaping ideological extremity, which helps explain why those at the far ends of the political spectrum come to view the world through a shared, extreme lens. (PsycInfo Database Record (c) 2025 APA, all rights reserved).