Cooperation is a cornerstone of human social organisation. The degree and scale of cooperation varies considerably across human populations and many authors attribute this variation to cultural differences. However, it remains unclear what drives this cultural variation. A substantial body of theory in evolutionary biology predicts that demographic characteristics of populations, such as their size and patterns of migration, may be important drivers of cooperation and competition. But these theoretical ideas have never been empirically tested in human populations, so it remains unclear whether evolutionary models are useful tools to explain variation in patterns of human cooperation. This study will be the first to empirically test these ideas in a set of real- world populations in order to investigate whether demographic influences on cooperation and competition explain the cultural variation observed across populations.
The study will generate a large-scale, longitudinal behavioural dataset of cooperative behavior in multiple populations of two small-scale Indian societies with contrasting patterns of migration. Economic games, behavioural surveys and quantitative behavioural observations will be used to measure levels of cooperation. These data will be used to test whether the contrasting patterns of migration in these two societies affect social networks and levels of cooperation.