The evolution of social systems in human and non-human primates

Thesis

From a Darwinian perspective, both history and environment are causal factors for change in animal social behaviour. Because behaviour leaves no fossil evidence researchers have focused on how social systems help animals and humans adapt to their current environments and have only been able to make tentative suggestions about how such systems may have evolved. However, a new theoretical framework, based on Darwin’s insights, allows phylogenetic relatedness to be incorporated into comparative analyses to discover the ancestral states of social behaviour and the ultimate drivers of change in human and primate societies.

This thesis uses these new methods to investigate the history and drivers of change in human and primate sociality and proposes a new model of primate social evolution. Analyses of mating systems suggest that social monogamy in humans and other primates is the result of infanticide risk brought about by life history changes. These methods were also able to reveal how changes in inheritance rules to matriliny among Bantu-speaking societies, contributed to a switch to matrilocal residence, which in turn contributed to a change from polygynous marriage to monogamy. Cultural history effects change in both descent and residence patterns, while geographical proximity also affects descent, but residence and environmental factors drive changes in marriage. This approach may provide a way for the various schools for the study of human and primate social behaviour to collaborate more closely and provide ultimate answers to the drivers of change in human society.

Authors: Opie, C; Christopher Opie

• Publication date: 2013
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: Oxford University, UK
• Language: English
• Keywords: Evolution; Language; Bantu; Primates; Kinship; Marriage; Bayesian Phylogenetics; Monogamy; Sociality
• Subjects: Anthropology; Evolution (zoology)