CHIMPS are not known for their manners, but it turns out they are more civilised than we give them credit for. They seem happy to help both unrelated chimps and unfamiliar humans, even if it means exerting themselves for no reward.
True altruism 鈥� completely unselfish acts for somebody else鈥檚 benefit 鈥� was until recently considered uniquely human. When animals help, the theory went, they either help relatives, thereby increasing chances of passing shared genes to the next generation, or they count on having favours returned in the future.
Now Felix Warneken and colleagues at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, have found that 12 of 18 semi-wild chimpanzees went out of their way to help an unfamiliar human who was struggling to reach a stick. They even did this when they first had to climb into a 2.5-metre-high ropeway and for no reward. Equivalent experiments with human toddlers gave similar results (PLoS Biology, vol 5, p e184).
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鈥淭his is the first evidence of chimpanzees helping somebody they don鈥檛 know,鈥� Warneken says, though he accepts the chimps may have helped because they associate humans generally with rewards. 鈥淏ut we also found they helped other chimps.鈥�
To show this, the team taught the apes to remotely unchain a door. When the chimps later saw another, unrelated, chimp trying to open the door, they unpegged the chain more often than when their peer wasn鈥檛 actively trying to get in. They chose to help the other chimp achieve its goal, Warneken suggests.
Primatologist Joan Silk at the University of California, Los Angeles, is intrigued because in previous studies unrelated chimps didn鈥檛 help each other. Warneken says apes in those experiments were so concerned with obtaining food that they did not appreciate that other chimps needed help. 鈥淭hey were in a completely different mindset,鈥� he suggests. But Silk thinks the difference might be the animals themselves: 鈥淲e should test the chimps from [Warneken鈥檚] study with the previous experiments,鈥� she says.
鈥淎pes may show spontaneous altruism more readily when the constraints of life in the wild are removed鈥�
Apes may show spontaneous altruism more readily when freed of the constraints of life in the wild, says Frans de Waal of Emory University in Atlanta, Georgia. He recalls captive young chimps helping an arthritic older female to climb a frame, and a male bonobo alerting zookeepers to young, unrelated bonobos drowning.
鈥淎nimals don鈥檛 know much about genetic kinship or future return favours,鈥� de Waal says, arguing that altruism could still be a self-serving trait, helping to win the 鈥渁ltruist鈥� a good reputation and higher status. 鈥淣atural selection has produced psychological mechanisms designed to produce spontaneous helping that 鈥� on average and in the long run 鈥� works to the advantage of both actors and recipients.鈥�
The details of such mechanisms need teasing out, but empathy is a hot candidate, says Warneken. He says the lack of rewards in his study suggests the chimps acted out of genuine concern for others.
