Friendship at Work: Inside the Black Box of Homophily

What explains friendship at work? The answer according to the homophily principle is that friendships are more likely among individuals who are similar. Classic work on homophily assessed similarity in terms of both demographic indicators and underlying cognitive perceptions. Organizational researchers, however, have tended to rely on a narrower, structural interpretation of homophily, one that assumes that perceptions of similarity can be bypassed because demography is a good proxy for these underlying perceptions. Using data from an organization located in North America, we open the black box of homophily and submit this assumption to empirical test. There was no support for the idea that the relationship between gender and friendship choice is mediated by underlying cognitive perceptions of similarity. We found, instead, that similarity in gender and perceptions of similarity were independently related to friendship choice. We also found evidence of heterophily when it comes to self-monitoring personality: the greater the difference in the self-monitoring scores of two individuals, the more likely they were to be friends. We close by discussing implications for theory and practice.