Friendship by assignment? From formal interdependence to informal relations in organizations

We offer the first field experiment showing how job assignments create social ties at work and influence their persistence. Pairs of managers were assigned at random to project teams. We show that once those pairs work together and become interdependent, they are more likely to create informal relationships (friendships and advice ties). Interdependence also increases the persistence of the informal ties that existed prior to team assignments; the magnitude of this effect decreases with tie strength. As organizations extend their use of teamwork, they also create and maintain social networks across functional and geographic boundaries. Thus, transitory project teams forge an enduring organizational legacy.