Beyond Dyads and Triads: A Comparison of Tetrads in Twenty Social Networks.

Social psychologists focus on the microlevel features that define interaction, often attending to dyads and triads. We argue that there also is utility in studying how configurations of four actors, or tetrads, pattern our social world. The current project considers the prevalence of directed tetrads across twenty social networks representing five relationship types (friendship, legislative co-sponsorship, Twitter, advice seeking, and email). By comparing these observed networks to randomly generated conditional networks, we identify tetrads that occur more frequently than expected, or network motifs. In all twenty networks, we find evidence for six tetrad motifs that collectively highlight tendencies toward hierarchy, clustering, and bridging in social interaction. Variations across network genres also emerge, suggesting that unique tetrad structural signatures could define different types of interaction.