Social Networks and Social Complexity in Female-bonded Primates

Abstract

Most primates are intensely social and spend a large amount of time servicing social relationships. The social brain hypothesis suggests that the evolution of the primate brain has been driven by the necessity of dealing with increased social complexity. This chapter uses social network analysis to analyse the relationship between primate group size, neocortex ratio and several social network metrics. Findings suggest that social complexity may derive from managing indirect social relationships, i.e. relationships in which a female is not directly involved, which may pose high cognitive demands on primates. The discussion notes that a large neocortex allows individuals to form intense social bonds with some group members while at the same time enabling them to manage and monitor less intense indirect relationships without frequent direct involvement with each individual of the social group.

Bridging the bonding gap: the transition from primates to humans

“…This tendency to concentrate on core relationships is evident from an analysis of network density and connectedness for female cercopithecoid primates (i.e. species of the baboon-macaque-guenon group, all of whom live in multi-female groups of 20-50 individuals) [42,53]. This species-level analysis shows that, as the number of reproductive females in the group increases, the female social networks of larger-brained species become increasingly less inter-connected (figure 4).…”

Baboon (Papio anubis) social complexity—a network approach

“…The networks presented in Figure 1 (including all observed relationships, no cut-off value employed) were all fully connected, without evidence for subgroups/cliques (analysis not shown). However, the use of a cut-off value, as suggested by some [James et al, 2009;Lehmann et al, 2010] would change the picture. In this study group, many individuals demonstrated strong links with one or two other individuals and much weaker links with many other group members; thus, the application of a 10% cut-off value produced networks that are much less well connected and that consist of more subgroups (unpub.…”

“…Our study provides a first overview of baboon social networks as based on a number of different behaviors, but more in-depth analyses investigating, for example, the structure, causes and consequences of such multiplex networks are needed to fully understand individual roles in their social environment [see also Sueur et al, 2011]. In addition, to test if social complexity indeed relates to the ability to maintain separate networks across different behaviors and to deal with indirect relationships, as suggested in Lehmann et al [2010], more data on a variety of species are needed.…”

“…the extent to which a network is fragmented into different subgroups) and overlap (i.e. the degree to which networks based on different behaviors are identical) may provide quantifiable measures for social complexity [Lehmann et al, 2010;Lehmann & Dunbar, 2009]. Our data suggest that olive baboons at Gashaka-Gumti National Park show an intermediate to high level of social complexity, as all network densities were around 0.4, which is at the low end of densities reported for primate networks [Kasper & Voelkl, 2009; 0.75 5 median density for 70 primate groups across 30 species, range 0.49-0.93].…”

“…Furthermore, species may differ in the number dimensions needed to describe their social environment. It has been hypothesized that in socially highly complex primates many behavioral dimensions may be needed to capture accurately an individual's social position, whereas in less socially complex species a few dimensions may be sufficient [Lehmann et al, 2010]. Thus, in socially complex species an analysis of only one part of the social environment (e.g.…”