Supporting Information: Punishment sustains large-scale cooperation in pre-state warfare
Abstract
The data were collected during 9.5 months of field work by Sarah Mathew from 2008– 2010. Participants were a representative sample of adult men reliant on nomadic pastoralism for their livelihood. We recruited them in a town close to the ethnic border frequented by nomadic Turkana who live in the surrounding 50 km radius. Recruitment was done with the help of trained local Turkana research assistants. The RA approached potential participants, briefly introduced them to the study, and then asked them to participate. If they agreed, they were brought to the study site described below. We conducted the study in the town center because the risk of raids in the surrounding nomadic settlements was high. We did not recruit from the settled Turkana population in this town center as they are Turkana who have actively pursued schooling and professions outside the pastoral sector, or were forced out of subsistence pastoralism after droughts, epidemics or raids. Nomadic Turkana frequent the perimeter of the town center for a variety of reasons as it is an important trading center and is adjacent to dry season watering holes. Herders from surrounding nomadic settlements frequent the market to sell an animal and purchase tobacco, tea, sugar and flour. Turkana women come to sell milk and collect relief food. Nomadic Turkana periodically come to town to visit their settled relatives. A river runs along the perimeter of town. The wells dug in the dry bed of the river provide water for 1 surrounding nomadic settlements and so herdsmen frequently bring their livestock for watering to the perimeter of town from where we can recruit them.To ensure that our sample is representative of herders within the town perimeter on a given day, we aimed to recruit using the following procedure to the extent that circumstances allowed: First, we specified the age-group that the participant should belong to. Then the RA went to one of the locations where nomadic herders visiting town are found..