US researchers comparing behavior of chimpanzees and children in a sharing game say the primates might possess a sense of fairness like that of human beings. Researchers from Georgia State University and the National Primate Research Center in Atlanta said the findings may help explain the role of altruism and fair play in human evolution, which in turn may shed light on the development of human social networks. The research was conducted using an \"ultimatum game,\" in which one player, the \"proposer,\" has the power to split a reward with another player, the \"recipient,\" the Los Angeles Times reported Tuesday. If only the proposer is allowed to decide how to split the reward, they often leave as little as possible for the recipient, but if the recipient has veto power over the reward -- preventing both players from getting anything at all -- the proposer is more likely to offer a 50-50 split. The researchers conducted the ultimatum game with 20 children ages 2 to 7, for a reward of stickers, and compared their play to that of six chimpanzees, playing for bananas. In both groups, the researcher found, the proposers tended to keep most of the rewards if given full control but tended to share equally if the recipient\'s approval was needed for the deal to go through, suggesting a similar sense of fair play among both the children and the chimps. \"[Because] cooperation was needed to gain rewards, it is possible that proposers were more generous because they were working with the respondent,\" the researchers reported in the Proceedings of the National Academy of Sciences, \"because involvement in a task may increase their sensitivity to inequitable outcomes.\"