October 5, 2007 Science. Researchers have demonstrated chimpanzees are more nakedly self interested than humans. I'd say "chimps are more like the textbook selfish rational actors than human players." UPI report says "Researchers from the Max Planck Institute of Evolutionary Anthropology in Leipzig studied the chimp's choices by using an economic game with two players. In the game, a human or chimpanzee who receives something of value can offer to share it with another.
If the proposed share is rejected, neither player gets anything.
Humans typically make offers close to 50 percent of the reward. They also reject as unfair offers of significantly less than half of the reward, even though this choice means they get nothing."