The Dynamics of Human Cooperative Groups

• Main Author: Thomas, MG
• Other Authors: Mace, R
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: UCL (University College London) 2015
• Subjects: cooperation; evolution; humans; behavioural ecology; anthropology; Norway; Northern Norway; saami
• Online Access: https://discovery.ucl.ac.uk/id/eprint/1473717/1/Thomas,%20MG.mgt%20thesis%20-%20final.pdf.REDACTED.pdf; https://discovery.ucl.ac.uk/id/eprint/1473717/

Humans live in cooperative groups of varying scales and composition, from families to nations and international communities. Segregating into groups can provide benefits by alleviating individual costs. However, individuals also face a dilemma between following their own interests and those of the group, which can lead to a breakdown in cooperation. The evolutionary benefits and costs of cooperation are well-understood theoretically, but the real-world dynamics of cooperative behaviour remain unclear. This thesis investigates cooperation in two populations, employing field experiments and social network methods grounded in a human behavioural ecology framework. Part I centres on Saami reindeer pastoralists, an indigenous minority who live and work in cooperative herding groups around northern Norway. I collected survey and experimental data, using gift games to test whether herders acted cooperatively towards genetic relatives or to their herding group, or both. I also played public goods games to understand how herders respond to and solve social dilemmas. Cooperative behaviours were biased towards the herding group, although kinship also had a positive effect on gift-giving. Smaller groups were more cooperative, although this pattern was not driven by relatedness. Part II analyses demographic and experimental data collected by others from a population of Mosuo farmers living in rural southwest China. The Mosuo are a minority whose social system traditionally revolved around matrilineal households but which is changing in response to increased tourism. The results show how affinal relationships encourage a real-word measure of cooperation: labouring on farms. Some Mosuo people were considered witches. I test whether witchcraft accusations act as a form of costless punishment, allowing people to withhold help from witches. Witches were somewhat isolated within their villages but clustered together and did not suffer significantly lowered reproductive success. These results underline the importance of studying ...