A study co-authored by a Haas School of Business professor and published this month uncovered a new perspective on how opposing groups interact by examining the relationship between U.S. senators’ voting trends and how much senators come in contact with one another.
Looking at roll-call voting trends collected from 1973 to 2009, Haas assistant professor Sameer Srivastava and University of Toronto assistant professor Christopher Liu found that the more Democrats and Republicans interacted, the more their voting behavior diverged. Meanwhile, senators of the same political affiliation voted more similarly as their interaction increased.
The study measured interaction between senators by their proximity in seating within the chamber and the number of committees they serve on together. Within the chamber, senators sit by party lines, with Democrats sitting on one side and Republicans on the other. According to the study, committees are determined with senators’ preferences taken into account.
Liu and Srivastava theorized that people with opposing affiliations who have close interpersonal contact in the public sphere tend to respond heavily to pressure based on their identity or affiliation.
“Even if you and I have a strong personal relationship, we may feel a normative pressure to conform to our respective identity groups,” Srivastava said.
According to the study, the conditions of the theory apply particularly to identity groups that are naturally oppositional, observable in the public sphere and already polarized.
The expectations of external influences, such as party donors and leaders, create pressure for Democrats and Republicans to diverge from one another in voting behavior, the study said. This can prove to be an obstacle to reaching consensus on various issues, resulting in political stalemates.
UC Berkeley sociology graduate student Shannon Ikebe, who was not involved in the study, cautioned against people who read the study from using it to make any explicit conclusions about what should be done in the U.S. Senate.
Srivastava emphasized a similar point, explaining that the study is not intended to find a solution to Congress’ ongoing polarization. Rather, the researchers want to reveal a general pattern in human behavior when it comes to interpersonal contact. According to Srivastava, this pattern can also arise during highly publicized company mergers and labor-management negotiations, when the parties are in opposition to each other.
“(The study is) not meant to be a policy paper, not meant to be a paper about how to arrange the seating chart in the Senate,” Srivastava said. “We wanted to uncover a more foundational social process, using the Senate as a model.”