The Science of Conservative vs Liberal Brains

Researchers have discovered that structural differences exist between the brains of conservatives and liberals.

What causes some people to identify as conservatives, and others as liberals? And why does that rarely change, once the die has been cast? Researchers have discovered that the answer may lie in more than influence from family and peers – there appears to be a biological factor at play.

Structural Differences in the Brains of Republicans and Democrats

It’s well-known that political identity is often polarising and a hill on which many are willing to die. Curious as to whether the makeup of the brain contributed to the stubbornness often exhibited in this area, researchers looked at the brains of Republicans and Democrats – and their findings support the idea that biology may indeed be relevant.

The study suggests that conservatives have greater sensitivity towards emotion and fear, and are more driven by these responses.

For this comparison, we’ll be looking at two specific areas of the brain, known as the amygdala, and the anterior cingulate cortex (ACC).

The amygdala is an almond-shaped structure associated with emotional and fear-based learning, and has notable differences between liberals and conservatives, with greater mass in the region of the latter¹. Essentially, this suggests that conservatives have greater sensitivity towards emotion and fear, and are more driven by these responses, as evidenced by a 2008 study².

Researchers played shocking noises to the two groups, and measured their blink response a known instinctual reaction to fear. They found that Republicans had a stronger response, an indicator of amygdala activity.

Another study³ found that disturbing images, such as those portraying infected wounds, aroused the conservative brain more than the liberal brain, indicating greater disgust sensitivity. Further, a 2013 study⁴ looked at emotional differences between Republicans and Democrats and discovered that risky decision-making caused the amygdalae of conservatives to fire at a greater rate than those of liberals.

In other words, it appears that the brains of conservatives are more sensitive to stimuli that carry emotional weight.

Liberals may be capable of demonstrating greater sensitivity towards issues which may not align with their habitual values.

On the other hand, studies have found that the liberal brain has greater volume in the ACC⁵, which has been linked to conflict detection and enables us to regulate our behaviour, by identifying discrepancies between habit-driven, instinctual impulses and our actual intentions.

Whilst distinguishing between instinct and intent, the ACC of Democrats also fires more frequently⁶. In the context of political policy, this may allow liberals to demonstrate greater sensitivity towards issues which may not align with their habitual values.

Since It’s Biologically Hardwired, Can Political Affiliation Ever Change?

Well, naturally a choice exists – but it may not be that simple, and in reality it rarely happens. While an obvious argument for this might be that political affiliation is a matter of values and deeply held principles, it has actually been shown⁷ that moral judgments are driven by political beliefs, rather than the other way around.

So what keeps individuals so steadfastly tied to their partisan beliefs? Again, this can be explained by neural obstacles getting in the way of allowing our minds to be changed.

The results suggest that genuine distress was experienced when presented with political ideologies which opposed their own.

A study prior to the 2004 presidential election asked volunteers to judge statements about candidates George W. Bush (Republican) and John Kerry (Democrat)⁸. Using neuro-imaging techniques, researchers were able to determine that when participants viewed information that contradicted their political leanings, certain areas of the brain showed increased activity.

The regions of the brain that were stimulated are those responsible for processing pain, negative emotion, and error detection. The results suggest that genuine distress was experienced when presented with political ideologies which opposed their own.

During a debrief, the volunteers were given an opportunity to justify their own stance, at odds with the material they’d been presented earlier. Brain scans showed increased firing in an area of the brain known as the ventral striatum, the region which manages reward and value processing – demonstrating at a neural level the pleasure involved in the participants’ rationalising their political beliefs.

the mechanism is more pronounced for political enthusiasts.

The combination of distress caused by opposing ideologies, and pleasure at justifying one’s own political preferences goes a long way to explaining the lack of motivation to be open to new or different political ideas.

And these neural mechanisms are actually heightened for those more heavily involved in politics, as evidenced by a 2010 study⁹. The study showed that while viewing statements consistent with their partisan ties, individuals more engaged in politics exhibit greater activity in the amygdala and ventral striatum.

In other words, the mechanism is more pronounced for political enthusiasts.

What Does This All Mean For the Future of Politics?

For better or worse, the research indicates that as time goes on, we tend to become more loyal to our partisan ties. And the stronger those affiliations, the less inclined we are to let go of them. Researchers suggest this creates a feedback loop, leading to people seeking out information which supports their beliefs¹⁰, essentially reinforcing their bias.

As we’ve discussed, on a biological level there is much which fundamentally goes against breaking these patterns. Of course, knowledge is power, so perhaps an awareness of the mechanisms at play will allow individuals to be more objective. But it doesn’t seem likely to occur at any significant scale.

Sources

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2. Douglas R. Oxley et al. ,Political Attitudes Vary with Physiological Traits.Science321,1667-1670(2008).DOI:10.1126/science.1157627
3. Smith KB, Oxley D, Hibbing MV, Alford JR, Hibbing JR (2011) Disgust Sensitivity and the Neurophysiology of Left-Right Political Orientations. PLoS ONE 6(10): e25552. https://doi.org/10.1371/journal.pone.0025552
4. Schreiber D, Fonzo G, Simmons AN, Dawes CT, Flagan T, Fowler JH, et al. (2013) Red Brain, Blue Brain: Evaluative Processes Differ in Democrats and Republicans. PLoS ONE 8(2): e52970. https://doi.org/10.1371/journal.pone.0052970
5. Kanai R, Feilden T, Firth C, Rees G. Political orientations are correlated with brain structure in young adults. Curr Biol. 2011 Apr 26;21(8):677-80. doi: 10.1016/j.cub.2011.03.017. Epub 2011 Apr 7. PMID: 21474316; PMCID: PMC3092984.
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7. Hatemi, Peter & Crabtree, Charles & Smith, Kevin. (2019). Ideology Justifies Morality: Political Beliefs Predict Moral Foundations. American Journal of Political Science. 63. 10.1111/ajps.12448
8. Drew Westen, Pavel S. Blagov, Keith Harenski, Clint Kilts, Stephan Hamann; Neural Bases of Motivated Reasoning: An fMRI Study of Emotional Constraints on Partisan Political Judgment in the 2004 U.S. Presidential Election. J Cogn Neurosci 2006; 18 (11): 1947–1958. doi: https://doi.org/10.1162/jocn.2006.18.11.1947
9. Gozzi M, Zamboni G, Krueger F, Grafman J. Interest in politics modulates neural activity in the amygdala and ventral striatum. Hum Brain Mapp. 2010 Nov;31(11):1763-71. doi: 10.1002/hbm.20976. PMID: 20162603; PMCID: PMC6870837.
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