Democrats Vs. Republicans: Scientists Explain What Brain Scans Revealed

Can scientists determine your political allegiance through a brain scan? The answer is "possibly," but probably not with high accuracy. Several studies have examined brain structure and activity among Democrats and Republicans with mixed results. Some studies that have more broadly looked at the brains of people who are politically conservative or liberal have also shown that there could be brain differences, but results on how accurately structural or functional differences in the brain relate to political opinions are mixed.

The anatomy of the human brain constantly surprises researchers, and new discoveries are being made each year. Parts of the brain that have been under investigation for plausible differences among liberals and conservatives include the insula, amygdala, and other areas that play a role in how you feel, reflect, make decisions, or act. The insula is thought to play an important role in your ability to feel internal sensations. The amygdala handles emotional processing and fear detection. Differences in fear processing among liberals and conservatives have been of particular interest to researchers. 

A significant amount of research also suggests that people who vote liberal or conservative have different psychological characteristics. Conservatives tend to have stronger attitudes toward threat and conflict, while liberals tend to be more likely to seek out novelty and uncertainty. In the United States' two-party system, Democrats seem to be more tolerant of risk than Republicans. Whether this psychological difference can be seen in brain imaging remains a matter of debate.

In a small 2013 study, researchers matched public voter records to the results of risk-taking tasks among 60 Democrats and 22 Republicans. The researchers sought to examine whether there were any differences in the risk-taking behaviors of the two groups or any differences in their brain activity. The researchers didn't find any difference in the level of risk-taking between the groups, but they did find some differences in brain activity. Democrats showed higher degrees of activity in the left insula while Republicans showed significantly greater activation of the right amygdala.

The researchers concluded that the results of this study provided evidence that conservatives show greater sensitivity to threatening stimuli. More research is needed to understand if there is a potential link (and to understand how strong the relationship might be). Not all research currently supports these findings. 

Twelve years later, in a 2025 study, researchers revisited the difference in brain activity among Democrats and Republicans while monitoring their brains with functional magnetic resonance imaging as people had to make food purchasing decisions. Unlike the 2013 study, the researchers in this study found evidence of higher activity in the left insula among Republicans compared to Democrats during a milk-choice experiment. This time, the researchers found no difference in amygdala activity between the two groups.

Some other teams of researchers have looked at potential brain differences among people more broadly liberal or conservative rather than strictly Democratic or Republican. It's been proposed that political conservatism could be associated with increased attention to negative or threatening stimuli. Activation of the amygdala has been theorized to at least partially explain these attention differences. 

In a 2024 study, researchers aimed to examine this connection by looking at a potential link between amygdala volume and political conservatism. They found a small association between higher amygdala volume and conservativeness but failed to show a statistically significant connection. The amygdala isn't the only part of the brain of interest to researchers. According to researchers in a 2026 review, there's also some evidence that right-wing authoritarianism may be inversely related to volume of the dorsomedial prefrontal cortex.

It's often said that you're left-brained or right-brained depending on which hemisphere of your brain is more active (largely a myth). On the left-wing to right-wing political spectrum, there's currently insufficient evidence to show that brain activity alone can show who you might vote for, but researchers still have a lot to learn about the human brain and they may find more evidence in the future. There's still so much to learn about the brain that scientists have been getting some of the structures in the brain wrong for nearly a century.