Women favour dyadic relationships, but men prefer clubs:cross-cultural evidence from social networking

The ability to create lasting, trust-based friendships makes it possible for humans to form large and coherent groups. The recent literature on the evolution of sociality and on the net- work dynamics of human societies suggests that large human groups have a layered struc- ture generated by emotionally supported social relationships. There are also gender differences in adult social style which may involve different trade-offs between the quantity and quality of friendships. Although many have suggested that females tend to focus on inti- mate relations with a few other females, while males build larger, more hierarchical coali- tions, the existence of such gender differences is disputed and data from adults is scarce. Here, we present cross-cultural evidence for gender differences in the preference for close friendships. We use a sample of *112,000 profile pictures from nine world regions posted on a popular social networking site to show that, in self-selected displays of social relation- ships, women favour dyadic relations, whereas men favour larger, all-male cliques. These apparently different solutions to quality-quantity trade-offs suggest a universal and funda- mental difference in the function of close friendships for the two sexes