Twenty groups of 9 to 11-year-old boys and girls from an Arab village in Israel played a game which required cooperative interaction among them to attain prizes. Half of the groups consisted of children of the same “Hamula” (extended family) and half of children from different Hamulas. It was found that boys were more cooperative than girls. Hamula boys were less cooperative than non-Hamula boys, and Hamula girls were more cooperative than non-Hamula girls. These Arab village results were compared with cooperation-competition among subjects from rural communities in Mexico, the Canadian Indian population, and Israeli kibbutzim.