From report on a study of the rules developed by East African hunter-gatherers (the Hadza) around sharing food:
Some camps share food more than others, but Hadza circulate among all camps rather than clustering in the most cooperative ones. Hadza individuals adjust their willingness to share food to the accepted standards, or social norms, of whatever temporary camp they live in, researchers report online September 20 in Current Biology.
Social norms develop in poorly understood ways. But factors such as the presence of prolific hunters probably encourage sharing in Hadza camps, says a team led by psychologists Coren Apicella and Kristopher Smith of the University of Pennsylvania. In groups with such norms, cooperators interact only with cooperators and don’t get taken advantage of by those who contribute no food, the researchers say.
…
Hunter-gatherers such as the Hadza represent the lifestyles of ancient people better than anyone else today does, says Harvard University anthropologist Joseph Henrich. Apicella’s findings raise the possibility that cooperation increasingly flourished as hunter-gatherer camps with more cooperative norms survived longer than camps with less cooperative norms, Henrich suggests. Bruce Bower, “The way hunter-gatherers share food shows how cooperation evolved” at Science News
The researchers enrolled Hadza adults in a co-operative game involving honey-filled straws…
Something about the whole account makes one feel queasy. The researchers are looking for a way that co-operation, in the human sense, evolved without any abstract thought being applied to the problem. But co-operation in the human sense probably couldn’t evolve that way because part of being human is the ability to evaluate the problem as an abstraction.
It’s hard to avoid uncomfortable comparisons of this research with research among chimpanzees.
Some of us would like to know more about why the Hadza have stayed with ancient ways when so few others have. Maybe they are like the Mennonites, for whom it is a chosen lifestyle? Maybe they are under threat? But, of course, that would mean studying them as if they have a history which they themselves know and respond to, that is, studying them as if they were human beings.
See also: Researchers: The selfish gene does not drive cooperation after all
and
Rob Sheldon on the failure of selfish gene theory and peacocks, as well as bees