Encouraging adversaries to have more interpersonal contact to find common ground may work on occasion, but not necessarily in the U.S. Senate, according to new research.

In their study, "Pulling Closer and Moving Apart: Interaction, Identity, and Influence in the U.S. Senate, 1973 to 2009," which appears in the February issue of the American Sociological Review, Sameer B. Srivastava, assistant professor, Haas Management of Organizations Group at UC Berkeley's Haas School of Business, and Christopher C. Liu, assistant professor of strategy at University of Toronto's Rotman School of Management, studied the interactions among U.S. senators from the 1970s to the 2000s.

A pattern emerged. Senators either moved closer together or further apart in their voting behavior as a function of their political identities and how much contact they had with each other. This pattern was especially pronounced when contact occurred in Senate committees that were more divided.

"Conventional wisdom says interpersonal contact between people will foster collaboration and consensus," says Srivastava. "We found that increasing physical contact between people who have opposing and public political identities can instead promote divergence of attitudes or behavior. This tendency is further amplified in environments involving high conflict, which makes political identities more salient."

Srivastava and Liu used two measures of political identity: senators' party affiliation and the religious climate in the senators' home states. They also measured senators' interactions in two ways: seating arrangements in the Senate chamber and committee assignments. Senators from the same party who had more contact -- as indicated by the proximity of their seats on the Senate chamber floor and by co-memberships on Senate committees -- subsequently moved closer together in their voting behavior, while senators from different parties who had more contact in later sessions of Congress moved further apart in their voting behavior.

"Co-location can induce both positive and negative outcomes. Sometimes keeping some distance is the better option," says Liu.

The authors say the U.S. Senate is an "apt setting for the study of interaction, identity, and influence" because senators have highly visible political identities and are continually seeking to influence each other through interaction. Srivastava and Liu contend that their findings also have implications in corporate organizations with oppositional political identities that are seeking to bridge differences between polarized groups.

For example, Liu and Srivastava explain, "Post-merger integration, particularly following a contested takeover, can produce oppositional identities in a very public setting. In such cases, it may help to move interactions into more private settings and find common ground on less divisive issues before tackling the more controversial ones."