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 benefit from their helping,” lead researcher Felix Warneken explains.
The same pattern showed up in a similar experiment with chimpanzees and humans: When a person with whom they had no prior relationship struggled to reach a stick, the chimps handed it to the person even when it required climbing up to a tall raceway. The chimps helped people just as often as 18-month-old German toddlers did in a similar setup involving a person struggling to reach a pen.
“The main finding is that humans and chimpanzees share altruistic tendencies,” Warneken says. In terms of evolution, he adds, this similarity suggests that the two species’ common ancestors had these inclinations before culture developed.
And that tells us something about human nature. “There’s a widely held belief that humans are selfish in the beginning and only through socialization do we turn into somewhat altruistic individuals,” Warneken says. This work suggests our nature contains the seeds for both types of behavior.
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