Chimpanzees can share a joke just like any human but they are also capable of sharing a laugh even when they don't find something particularly funny, scientists have discovered.
A study of wild chimpanzees has found that laughter occurs not just when chimps are having fun but also when they want to promote some kind of social bonding – much like human smiles help bonding in a conversation.
"Humans clearly use laughter as an important response in a wide range of social situations, but it is particularly interesting that chimpanzees seem to also use laughter to respond in such distinct ways.We found their responsive laughter shows a similarity to the conversational laughter of humans." said psychologist Dr Marina Davila-Ross of Portsmouth University.
According to Dr Davila-Ross this behaviour shows that great apes have a more complex social use of expressions than previously thought: “They do not just mimic the expressions of their playmates; they respond with their expressions in more complex ways than we were aware of before. We found their responsive laughter shows a similarity to the conversational laughter of humans. Both are shorter than spontaneous laughter and both seem designed to promote social interaction. These sorts of responses may lead to important advantages in co-operation and social communication - qualities that help explain why laughter and smiles have become integral tools of emotional intelligence in humans.”
The research, published in the journal Emotion, showed that responsive laughter in apes was shorter than compulsive laughter and prolonged play which has a vital role in the physical, emotional, social and cognitive development of both chimpanzees and humans. The study also showed that compulsive laughter was evident at a younger age than responsive laughter.
The study examined laughter in 59 chimpanzees living in four groups in the chimpanzee sanctuary Chimfunshi Wildlife Orphanage in Zambia. Two of the groups had been established for more than 14 years, and two groups had been living together for less than five years and all contained a mixture of ages and sexes. Nearly 500 play bouts were video recorded and in all cases, playing sessions lasted significantly longer when one playmate joined in the laughter of another.
Dr Davila-Ross said that the laughter exhibited was not 'fake laughter', which was exclusive to humans, but simply the chimpanzee joining in with a playmate's laughter. She added that the apes had to be part of the fun to start laughing and would not just laugh by hearing other apes laughing nearby.
Dr Davila-Ross said that laughter might have played an important part in human evolution: “Selection pressures might have favoured individuals who use their laughter in socially distinctive ways. The phenomenon of a laugh triggered by the laughter of others seems to be deeply rooted in primate evolution. Apes and monkeys also copy the expressions of other apes, such as yawning and play faces.” She added: “Five million years ago the ancestors of apes and humans must have produced laughter as rather honest social responses. Since then, the ability to control laughter must have drastically increased, along with its adaptive advantages, which explains why laughter has become a highly sophisticated, ubiquitous tool of co-operation and social communication in humans.”
Some scientific study of wild animals such as chimpanzees take place using captive animals in unnatural and inevitably stressful invasive zoo or laboratory conditions where the animals are unlikely to behave normally and likely to behave abnormally. However the beauty of studies like this one is that scientists get to observe the natural behaviour of these wonderful creatures. By simply observing these rescued animals, who are so like us in so many ways, we are not only learning more about them but about ourselves too.