Chimp off the old block: humans still understand gestures made by great apes

Chimpanzees use lots of different gestures to communicate, like this 'reach' which they usually use to ask for food <i>(Image: Catherine Hobaiter)</i>
Chimpanzees use lots of different gestures to communicate, like this 'reach' which they usually use to ask for food (Image: Catherine Hobaiter)

HUMANS can recognise and understand gestures made by chimpanzees and bonobos, according to a study by the University of St Andrews.

Although we no longer use them ourselves, people correctly identified more than half of the gestures made by the primates in an online study of 5500 participants run by Dr Kirsty Graham and Dr Catherine Hobaiter from the School of Psychology and Neuroscience.

Dr Graham said: “All great apes use gestures, but humans are so gestural – using gestures while we speak and sign, learning new gestures, pantomiming etc – that it’s really hard to pick out shared great ape gestures just by observing people.”

Viewers watched short videos of the 10 most common gestures used by chimpanzees and bonobos, and they were then asked to select the meaning of the gesture from four possible answers.

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Results revealed that participants correctly interpreted the meaning of the gestures more than 50% of the time.

When provided with additional information on context, there was a small effect on success, suggesting that humans can correctly identify ape gesture meanings from the gestures themselves.

Although data is no longer being collected, an online quiz version of the experiment is still available.

It is possible we have retained an understanding of this ancestral communication system of our closest living relatives.

Dr Hobaiter said: “On one hand it’s really incredible that we’re able to do this – Kirsty and I have spent years living in the forest with chimpanzees and bonobos and working hard to study their communication.

“But it turns out that perhaps we didn’t need to! We can decode these gestures almost instinctively.

“It’s a useful reminder that we are also great apes! And that, even though today modern humans have language, we’ve kept some understanding of our shared ancestral system of ape communication.”

The research adds to decades of work where scientists have carefully recorded and studied the meanings of the almost 100 different ape gestures.

Video playback experiments have been used to test language comprehension in non-human primates, but this study reversed the paradigm to assess humans’ abilities to understand the gestures of primates for the first time.

The PLOS Biology paper is available at https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3001939