Mechanisms of reciprocity and diversity in social networks: a modelling and comparative approach

Three mechanisms have been proposed to underlie reciprocation of social behaviors in gregarious animals: ‘calculated reciprocity’, ‘emotional bookkeeping’ and ‘symmetry-based reciprocity’. Among these explanations, emotional book-keeping has received the broadest support from experimental and observational studies. On the other hand, three individual-based models have shown that reciprocation may emerge via ‘symmetry-based reciprocity’, ‘emotional bookkeeping’, or a combination of both mechanisms. Here we use these three models to assess their relative fit with empirical data on reciprocation and social network structure across different groups and species of macaques. We collected grooming data from 14 groups and 8 macaque species and simulated each group in each model. We analyzed and quantitatively compared social network metrics of the empirical and the models’ grooming networks. The three models captured fairly well the features of observed networks, and fitted data from wild group...