For years, lacking evidence to the contrary, most scientists had assumed that altruism is unique to humans. Sure, other primates groom each other and even share food, but this kind of helping could be chalked up to selfish motives—either to benefit close relatives who share their genes or to get an immediate reward. In June, however, scientists from the Max Planck Institute for Evolutionary Anthropology reported the first experimental evidence of spontaneous altruism in chimpanzees, toward both nonrelated chimps and humans.
In one experiment done with semifree-ranging chimps in Uganda, a chimp struggled to open a door locked by a chain. The researchers wanted to see if a second chimp would release the chain to help the first get food. Three-quarters of the time, the chimps in a position to help did just that. “The crucial thing here is they help without any expectation of being rewarded, because they don’t ...
