Evolving political views linked to changes in brain activity

When people alter their political loyalties, the way their brains respond to political messages changes alongside those shifting allegiances. A small study tracked individuals over two and a half years and found that evolving feelings about political groups altered brain activity in regions related to emotion and memory. These results, published in Communications Psychology, detail how social identity deeply shapes the way the human brain processes political information.

Political identity has traditionally been measured by a person’s abstract beliefs or policy preferences, such as identifying as liberal or conservative. In recent years, political polarization has become more personal, with group loyalty often overriding specific policy positions. Many voters now view politics through a lens of strict group membership, prioritizing whether a politician belongs to their specific faction over the details of proposed legislation. This shift has led researchers to ask how changes in worldview manifest physically within the brain over time.

Most neuroimaging studies compare different groups of people at a single moment in time. Very few track how an individual’s neural responses to the exact same information might shift as their own perspectives evolve. Finding an environment to test this is difficult, because adult political opinions tend to remain stable under normal conditions.

The research was conducted by neuroscientists Gal Boiman, Tal Ohad, and Yaara Yeshurun at Tel Aviv University, along with their colleagues Yohay Zvi and Noa Katabi. The team took advantage of a prolonged period of political instability in Israel starting in 2019. During this time, repeated elections and unexpected alliances disrupted traditional party lines, creating a rare opportunity to observe people as their political loyalties shifted in real time.

To study this phenomenon, the researchers recruited a group of participants for an initial brain scanning session in April 2019. More than two years later, in August 2021, 21 of those individuals returned for a second scan. Because the sample included fewer than 50 participants, it is considered a small study. During both sessions, participants lay inside a functional magnetic resonance imaging scanner, a machine that measures brain activity by tracking blood flow.

While inside the scanner, the participants watched identical sets of videos. The video clips included campaign advertisements from left-wing, right-wing, and centrist parties, as well as speeches by political figures. A documentary clip about a man who converted an old bus into a house served as a neutral baseline.

After each scanning session, the participants answered extensive questionnaires in a separate room. These surveys measured their agreement with the videos, their emotional engagement, and their specific sentiments toward the political figures shown. The questions asked participants to rate feelings like trust, pride, anger, and disgust. During the 2021 session, participants also answered questions about how their opinions had changed since the first viewing.

The research team used the survey responses to calculate a score representing how much each person’s interpretation of the videos had altered. They divided these changes into two main categories. One category measured shifts in abstract ideology, such as opinions on specific government policies. The second category measured changes in group identity, capturing how participants felt about specific politicians and political factions.

Next, the researchers compared the brain scans from 2019 with the scans from 2021. They looked for differences in brain activity across thousands of tiny, three-dimensional blocks of brain tissue, known as voxels. The researchers mapped these differences to see which parts of the brain changed the most and which remained stable. To ensure accuracy, they filtered out baseline changes that occurred when participants watched the neutral documentary video.

The analysis revealed a hierarchy of brain adaptation. Brain regions responsible for basic sensory processing, such as the visual and auditory cortices, showed the least amount of change between the two sessions. When participants watched the same videos two years later, their visual and auditory centers reacted in almost the exact same way.

In contrast, the largest differences in brain activity appeared in areas deep within the brain that manage memory, emotion, and reward. These areas included the amygdala, the hippocampus, and the striatum. The amygdala helps process emotional reactions, the hippocampus is heavily involved in forming and retrieving memories, and the striatum plays a role in recognizing rewards.

The researchers then looked for links between the altered brain activity and the survey scores measuring shifts in interpretation. They found that changes in brain activity directly correlated with how much a participant’s interpretation of a video had changed. The brain activity shifted the most when participants watched videos of politicians who had made unexpected alliances or changed their political positioning during the two-year gap.

When the researchers separated the survey scores into ideology and group identity, a distinct pattern emerged. The alterations in brain activity were strongly associated with changing feelings about political groups and specific figures. In contrast, the relationship between brain activity and changes in abstract ideological beliefs was not statistically significant. This suggests that shifting loyalties to a political team are more closely tied to how the brain processes information than changing opinions on policy.

The study design relies on observing natural changes over time, meaning it can only identify associations rather than establish direct causes. It remains unknown whether changing political attitudes cause the brain’s processing pathways to alter, or if underlying neural shifts lead to new political attitudes. The authors note that the small sample size prevented them from comparing different demographic groups, such as strictly conservative versus liberal voters. This limitation makes it impossible to say if one end of the political spectrum experiences these brain changes differently than the other.

The findings also depend on real-world political developments, which introduces some contextual variables. A participant might interpret a video differently in 2021 not just because their internal worldview changed, but because the politician in the video had taken new actions in the real world. Future research could use controlled laboratory settings to isolate personal shifts in opinion from external political events.

The study, “Changes in political attitudes are associated with changes in neural responses to political content,” was authored by Gal Boiman, Tal Ohad, Yohay Zvi, Noa Katabi, and Yaara Yeshurun.