In the United States, the polarization between liberals and conservatives is profound. Each political side prefers others like them. People even seek out others with similar political beliefs for romantic connections.¹ What causes these differences to run so deep? The answer may lie in the brain. Researchers have found significant brain differences between liberals and conservatives. Here are some partisan brain differences, and why they may be important.
Anterior Cingulate Cortex
The anterior cingulate cortex (ACC) is a part of the brain that connects rewards to actions.² In a study on empathy, when researchers blocked ACC activity in rats, they were less helpful towards distressed rats than the control.³ Helping another being and reducing their distress is an adaptive response. The ACC helps connect the action of helping to the positive outcome or “reward” of such behavior.² Once the brain connects these two concepts, one is much more likely to do the action that will cause a reward.
In neuroimaging studies, liberal people have higher ACC activity than conservative people.⁴ This implies that they are more likely to take new actions based on new information.⁵⁻⁶ In contrast, conservative people prefer to maintain stability and reduce ambiguity when possible.⁵ Thus, they are less likely to envision a reward with a new course of action.
Another part of the brain that differs between liberal and conservative people is the amygdala. The amygdala processes emotional stimuli.⁵ Researchers thought it mainly responded to threat,⁶ but recent research suggests that it responds to all kinds of stimuli.⁷ So, greater amygdala activity would suggest a greater response to emotional stimuli.
Conservative people tend to have greater amygdala volume and activity than liberal people.⁶ This is especially true of the right amygdala, which responds to negative emotional stimuli.⁵ But Tritt and colleagues found that conservative people react more to all kinds of stimuli, not just negative ones.⁷ Thus, conservative people may place more importance on emotional issues.
In addition to differences in the brain, liberal and conservative people think differently as well. Bryan Buechner, a professor at Xavier University, has studied the effect of partisanship on cognition. “There’s an overwhelming amount of literature about political ideology differences,” he says, “but there isn’t a lot about how liberals and conservatives think differently.” He and his colleagues studied these differences.⁸ Conservative people did well at response inhibition, and liberal people did well at response-updating.⁸ According to Buechner, habits are a good real-life example of these cognitive functions. When a person is trying to form a new habit and ignore distractions, “inhibition is crucial,” he says. “When you try to change a habit, however, and you’re trying to modify your behavior, then updating and flexibility are going to come into play.”
According to this study and others like it, liberals and conservatives think differently. But, it is important to remember that “different” doesn’t mean better or worse. “While the thinking styles are different, they each have their own benefits and consequences,” Buechner says. The same goes for brain differences. There is no evidence to suggest that liberal or conservative people have better ways of thinking or being. Learning about the partisan nature of the brain doesn’t prove any political point. But, it does help us understand why the United States is so divided. It is hard to understand people with such inherent differences. But, by understanding said differences, we can take a step toward healing our divided nation.
1 Klofstad, C. A., McDermott, R., & Hatemi, P. K. (2013). The dating preferences of liberals and conservatives. Political Behavior, 35(3), 519–538. https://doi.org/10.1007/s11109-012-9207-z
2 Rolls, E. T. (2019). The cingulate cortex and limbic systems for emotion, action, and memory. Brain Structure & Function, 224(9), 3001–3018. https://doi.org/10.1007/s00429-019-01945-2
3 Yamagishi, A., Lee, J., & Sato, N. (2020). Oxytocin in the anterior cingulate cortex is involved in helping behaviour. Behavioural Brain Research, 393, 112790. https://doi.org/10.1016/j.bbr.2020.112790
4 Weissflog, M., Choma, B. L., Dywan, J., van Noordt, S. J. R., & Segalowitz, S. J. (2013). The political (and physiological) divide: Political orientation, performance monitoring, and the anterior cingulate response. Social Neuroscience, 8(5), 434–447. https://doi.org/10.1080/17470919.2013.833549
5 Mendez, M. F. (2017). A Neurology of the Conservative-Liberal Dimension of Political Ideology. The Journal of Neuropsychiatry and Clinical Neurosciences, 29(2), 86–94. https://doi.org/10.1176/appi.neuropsych.16030051
6 Jost, J. T., & Amodio, D. M. (2012). Political ideology as motivated social cognition: Behavioral and neuroscientific evidence. Motivation and Emotion, 36(1), 55–64. https://doi.org/10.1007/s11031-011-9260-7
7 Tritt, S. M., Peterson, J. B., Page-Gould, E., & Inzlicht, M. (2016). Ideological reactivity: Political conservatism and brain responsivity to emotional and neutral stimuli. Emotion, 16(8), 1172–1185. https://doi.org/10.1037/emo0000150
8 Buechner, B. M., Clarkson, J. J., Otto, A. S., Hirt, E. R., & Ho, M. C. (2020). Political ideology and executive functioning: the effect of conservatism and liberalism on cognitive flexibility and working memory performance. Social Psychological and Personality Science, 194855062091318. https://doi.org/10.1177/1948550620913187