A study recently published in Political Psychology sheds new light on how biology influences political behavior. The findings indicate that differences in psychophysiology are associated with the political homogeneity of a person’s social network.

In other words, a person’s physiological reactivity is linked to whether they discuss politics with people who share their own views.

“This project was a unique blend of all of our research interests. My co-author Jaime is really interested in how individual biological and psychological differences between people are associated with political behavior, especially with respect to how we respond to political contention,” said study author Taylor N. Carlson, an assistant professor at Washington University in St. Louis.

“My other co-author Charlie is interested in youth representation and political engagement. While his work is largely focused in Japan, he is also interested in social network analysis, which made him a vital member of our team.”

“The natural blend of our research interests alongside the increasingly contentious political interactions we observed in our daily lives motivated us to conduct this study,” Carlson said.

In the study, 129 undergraduate students from a political science class completed a large online survey regarding their political beliefs, personality, and other factors. The survey also assessed who the participants discussed politics with in their classroom.

Later, 79 of these students were included in a follow-up lab study. The researchers monitored the skin conductance and heart rate variability of the participants during the lab experiment, in which they were informed that they would be having a political discussion with another person.

The researchers found that those who scored higher on a measure of social anxiety were more likely to discuss politics with other students who shared their political leanings. The same was true of participants who experienced a greater increase in heart rate when anticipating a political discussion.

“There are a few things that we hope individuals take away from our study. First, we show that even anticipating a political discussion can be associated with physiologically uncomfortable feelings, such as sweaty palms and racing hearts,” Carlson told PsyPost.

“Second, and more important to our study, we show that individuals who have stronger physiological responses (e.g. their heart rates increase more) to a possible political discussion, as well as individuals who might be socially anxious, are more likely to discuss politics with people who are like-minded.”

But the study — like all research — includes some limitations.

“One major limitation of the study is that the results are purely correlational — we do not know, for example, if individuals who are more socially anxious or physiologically reactive to discussion choose to discuss politics with like-minded copartisans (perhaps in an effort to avoid uncomfortable feelings), or whether individuals who choose to discuss politics with copartisans had larger physiological reactions in our study because there was a possibility that their discussion would be with someone who disagrees,” Carlson explained.

“Another limitation is that our physiological measures cannot capture whether individuals were experiencing positive or negative emotions. While previous research has shown that an increase in heart rate is associated with many negative emotions, it can sometimes also be associated with more positive emotions like excitement.”

“We try to address this with some self-reported emotional response data in the study, but we ultimately cannot be sure whether the physiological measures reveal positive or negative emotions,” Carlson said.

“The last limitation I’d like to note here is that our study relied on a relatively small sample of college students, so we do not know if these results would generalize to other groups.”

“This project was a wonderful collaborative effort that would not have been possible without amazing research assistance from members of the Social Networks and Political Psychology (SNaPP) Lab: Dan Brown, Karina Charipova, Michelle Hermes, Edward Hernandez, Zarine Kharazian, Sahil Mehrotra, and John Stuart. Collecting physiological data in studies like this requires a lot of time, patience, and resources, for which we also thank the National Science Foundation (SES 1423788),” Carlson added.

The study, “Follow Your Heart: Could Psychophysiology Be Associated with Political Discussion Network Homogeneity?“, was authored by Taylor N. Carlson, Charles T. McClean, and Jaime E. Settle.