Chimpanzees and humans may have age-old common language

New research published this month in the scientific journal PLOS Biology shows that apes and humans may share a common innate communication system. This may have formed the starting point for our own gestures and body language. Chimpanzees perform a wide variety of gestures to communicate with their peers, for example scratching the mouth may signal "give me food", while beckoning with fingers pointed down means "come here".

When humans in a study were tested to see if they could interpret a variety of wild chimpanzee gestures, researchers were surprised to find out that they performed much better than expected. Correctly interpreting more than half of chimpanzee body language signals, the study suggests that understanding ape language is something we can still do instinctively, and that many of our own gestures, thought to be uniquely human, may in fact be more universal than first thought.

Such visual communication also held similarities with other species of great apes, such as orangutans and gorillas. Many of the same movements are also used by human infants before they learn to speak. All this points to the hypothesis that the origins of language were held by a common extinct great ape ancestor that lived several million years ago.

In the study, signals such as scratching across the chest meant "groom me", and shaking trees indicated "let's mate". Some were more relatable to the human participants than others, with particular clear differences in how smiles were interpreted between species.

Although indicating friendly intentions in humans, smiling among chimpanzees indicates aggression, through baring the canines to threaten a bite. Nevertheless, humans were able to correctly interpret more than half of the visual gestures, something which surprised the researchers at St Andrews University.

Universal gestures included "move over a little", through lightly nudging another chimp with a hand, with grabbing hard with eye contact meaning "stop that now". More obscure gestures which were not universal among humans included leaf clipping, where chimps would take small bites out of a leaf to signal flirtation, and showing another the bottom of their foot, to ask the young to climb onto their back.

Chimpanzee brains are capable of extremely sophisticated social interaction, with each ape capable of intelligently inferring meaning from simple and often vague gestures. Such signals can be unique to specific isolated groups or even between two individuals.

In the 1970s, chimpanzees were successfully taught American Sign Language and were able to recite over 240 words to both keepers, and to communicate with one another. One chimpanzee called Washoe even taught the signs to her own son without being directed to by researchers.

It is estimated that humans share up to 99 percent of DNA with chimpanzees, meaning that our ability to understand some of their communication is not surprising. As we continue to understand the composition of human language, it is important to understand its roots so that we can learn more about our own language capabilities.

The chimpanzee is by far the noisiest ape, screaming, grunting and whimpering to communicate in small groups in the wild. However, this pales in comparison to the hundreds of sounds the human vocal organs can produce. The journey our own language has taken to get to this point remains an ongoing mystery.

Barry He is a London-based columnist for China Daily