September 8, 2008
Researchers Say Hugging Benefits Chimps
Researchers at Chester Zoo say chimps may receive the same feelings of consolation from physical contact as humans.
The research could provide the first evidence that consolation in primates, such as hugging and stroking, can reduce stress levels after a fight.
Dr. Orlaith Fraser said the behavior could indicate some level of empathy.
"We can't actually say what's going on in a chimpanzee's mind; we can only deduce from their behavior what's going on," the Liverpool John Moores University researcher said.
"Because this behavior is actually reducing stress levels and it's being offered by a valuable partner, it seems likely that this is an expression of empathy."
The researchers spent 18 months observing 22 adult chimps at Chester Zoo.
They observed everything that happened immediately after the animals had a scrap - perhaps a fight over food, a mate or simply where to sit.
In about 50% of cases, another member of the group would console the victim in the fight. A close friend, a chimp with which the victim would routinely play or share food, always did the soothing.
The consolation usually took the form of a kiss or embrace, a grooming session or even play.
The activity had the effect of reducing stress levels, indicated by the return to the animals' normal activities of self-scratching and self-grooming, scientists said.
"Sympathetic concern" has also been observed in gorillas, bonobos, dogs and even rooks - but it is the calming effect that it had on the Chester Zoo chimps, which is said to be a new observation.
"If these chimpanzees are actually motivated by empathy to console victims of aggression, they must first of all be able to recognize that the victim is distressed and then they must know what to do in order to act appropriately to respond to this distress," said Fraser.
"This is something often thought to be a unique trait to humans, so understanding the link between consolation and stress reduction in chimpanzees is an important step towards understanding whether or not chimpanzees are capable of this level of empathy."
The results of the Chester Zoo study were recently published in the journal Proceedings of the National Academy of Sciences.
On the Net: