Most of our nearest relatives are, like us, social beings, forcing them to find ways to cooperate. Chimpanzees are no exception, and a study of them performing group tasks has found strong parallels with the way humans combine, suggesting this behavior has deep evolutionary roots.
To test chimpanzee cooperation, a team led by famed primate researcher Professor Frans de Waal of the Yerkes National Primate Research Center challenged a group of 11 adult chimpanzees to cooperate for a reward. One chimp had to remove a barrier while another pulled in a plate carrying a piece of fruit. No individual could manage both roles on their own. Subsequently, the challenge was altered to require a third participant.
The scenario was obviously different from one the apes would have been familiar with, and they took some time to understand how it worked. Nevertheless, they managed well. In Proceedings of the National Academy of Sciences, the team reports that some chimps tried to “freeload” by letting others do the work and then stealing the food themselves, or not sharing with their co-worker. However, effective mechanisms developed to punish this, and over the thousands of successful fruit captures, cooperative acts outnumbered those where one chimpanzee cheated by five to one.
After a piece of fruit had been delivered the plate would be immediately refilled, and this went on for an hour at a time. Consequently, fights that interfered with this would eat into the total amount of fruit that could be captured in the space of an hour. This seldom happened. In the space of 94 test sessions, 3,656 pieces of fruit were captured, despite the fact that the chimpanzees were relatively new to each other and still in competition to establish social rank.