Humans Can Understand Gestures Made By Apes, New Study Finds
Michelle Milliken
Apes communicate with each other through gestures made with their limbs and hands, much like humans. Though chimpanzees and humans split off in different directions from a common ancestor at least 6 million years ago, a new study finds we still understand their language.
Researchers at the University of St Andrews in Scotland used videos of chimpanzees and bonobos to gauge how well people could interpret their gestures. According to findings published in the journal PLOS Biology, humans are still able to crack the code more than half the time. The team says this suggests we hold onto some of our shared language from millions of years ago.
Dr. Kirsty Graham, co-lead researcher from St Andrews' School of Psychology and Neuroscience, says, "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. By showing participants videos of common great ape gestures instead, we found that people can understand these gestures, suggesting that they may form part of an evolutionarily ancient, shared gesture vocabulary across all great ape species, including us."
To determine if people were able to understand the apes' communication, the researchers had more than 5,500 people watch 20 short videos, which showed 10 of the gestures most frequently used by chimpanzees and bonobos. The participants were then asked to interpret the meaning behind these movements from four different choices. More than 50% of the time, they chose the right answer. Receiving additional context behind the communication wasn't found to help much, so the researchers say that may mean humans inherently understand the gestures.
The team says this may demonstrate evolutionary continuity between the communication of humans and apes.
Dr. Catherine Hobaiter, also co-lead researcher from the School of Psychology and Neuroscience, explains, "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 researchers say it's unclear if we inherited the understanding, or our commonalities with apes - like general intelligence, physical resemblance, and similar social goals - make it easier to understand each other.
