Fragmentation or integration? Ethnic diversity and the structural cohesion of adolescent social networks

Abstract

This paper addresses a key yet untested proposition in social cohesion research: ethnic diversity fragments social networks and leads to an overall reduction in network connectivity—that is, a decline in structural cohesion. Homophily might lower structural cohesion especially in contexts where just a few ethnic groups of similar size are present (i.e., at medium diversity levels) and where ethnic boundaries coincide with other demographic differences such as along gender and socioeconomic status, a pattern known as attribute consolidation. However, structural cohesion might be higher again in very diverse contexts, where other network mechanisms, including sociability, may override ethnic homophily. We analyse the structure of friendship networks as they emerge in N = 1,318 German school classrooms to test these claims. Results show that structural cohesion is lowest in classrooms with medium ethnic diversity. Networks there are more fragmented than in both homogeneous and highly diverse classrooms, where they are better connected. However, the correlations are very small, suggesting that network fragmentation in diverse schools is not substantial. Further, attribute consolidation is unrelated to structural cohesion. These findings suggest that even though ethnic homophily shapes adolescents’ friendship formation , it seems to have only a minor influence on the structural cohesion of the emerging friendship networks.