Best Friends Forever? Modeling the Mechanisms of Friendship Network Formation

The formation of friendships and alliances is a ubiquitous feature of human life, and likely a crucial component of the cooperative hunting and child-rearing practices that helped our early hominin ancestors survive. Research on contemporary human beings typically finds that strong-tie social networks are fairly small, and reveals a high degree of physical (e.g., age) and social-structural (e.g., educational attainment) homophily. Yet, existing work all too often underestimates, or even ignores, the importance of abstract, symbolic homophily (such as shared identities or worldviews) as a driver of friendship formation. Here we employ agent-based modeling to identify the optimal variable wei…