Laboratory of Comparative Ethology, Eunice Kennedy Shriver National Institute for Child Health and Human Development, National Institutes of Health, Poolesville, Maryland.
Neuroscience and Behavior, California National Primate Research Center, University of California, Davis, California.
Am J Primatol. 2020 Nov;82(11):e23024. doi: 10.1002/ajp.23024. Epub 2019 Jun 26.
Social network analysis is increasingly common in studying complex interactions among individuals. Across a range of primates, high-ranking adults are generally more socially connected, which results in better fitness outcomes. However, it still remains unclear whether this relationship between social network position and dominance rank emerges in infancy and whether, in species with a social transmission of dominance rank, social network positions are driven by the presence of the mother. To fill this gap, we first explored whether dominance ranks were related to social network position, measured via eigenvector centrality, in infants, juveniles, and adults in a troop of semi-free-ranging rhesus macaques (Macaca mulatta). We then examined relationships between dominance rank and eigenvector centrality in a peer-only group of yearlings who were reared with their mothers in either a rich, socially complex environment of multigenerational (MG) kin support or a unigenerational group of mothers and their infants from birth through 8 months. In Experiment 1, we found that mother's network position predicted offspring network position and that dominants across all age categories were more central in affiliative networks (social contact, social grooming, and social play). Experiment 2 showed that high-ranking yearlings in a peer-only group were more central only in the social contact network. Moreover, yearlings reared in a socially complex environment of MG kin support were more central. Our findings suggest that the relationship between dominance rank and social network position begins early in life, and that complex early social environments can promote later social competency. Our data add to the growing body of evidence that the presence/absence of the mother and kin influence how dominance rank affects social network position. These findings have important implications for the role of caregivers in the social status of developing primates, which ultimately ties to health and fitness outcomes.
社会网络分析在研究个体之间复杂相互作用方面越来越普遍。在一系列灵长类动物中，高等级的成年人通常具有更多的社交联系，从而导致更好的适应结果。然而，目前仍不清楚这种社交网络位置和支配等级之间的关系是否在婴儿期就出现了，以及在具有社会传递支配等级的物种中，社交网络位置是否由母亲的存在驱动。为了填补这一空白，我们首先探索了支配等级是否与通过特征向量中心度测量的婴儿、青少年和成年猕猴（Macaca mulatta）群体中的社交网络位置有关。然后，我们在一个仅由同龄个体组成的群体中检查了支配等级和特征向量中心度之间的关系，这些个体在一个丰富的、具有多代（MG）亲属支持的复杂社会环境中与母亲一起成长，或者从出生到 8 个月与母亲及其婴儿一起成长在一个单代群体中。在实验 1 中，我们发现母亲的网络位置预测了后代的网络位置，并且所有年龄段的支配者在亲和网络（社交接触、社交梳理和社交游戏）中都更加中心。实验 2 表明，仅在同龄群体中，高等级的同龄个体在社交接触网络中更加中心。此外，在具有多代亲属支持的复杂社会环境中抚养的同龄个体更加中心。我们的发现表明，支配等级和社交网络位置之间的关系在生命早期就开始了，并且复杂的早期社会环境可以促进后期的社交能力。我们的数据增加了越来越多的证据，即母亲和亲属的存在/缺失会影响支配等级如何影响社交网络位置。这些发现对照顾者在发展中的灵长类动物的社会地位中的作用具有重要意义，这最终与健康和适应结果有关。
