Image source, Cat Hobby
Wild chimpanzees, like humans, engage in agile turn-taking conversations, waiting only a split second for their turn to “speak.”
Animals communicate primarily through gestures, such as hand movements and facial expressions.
Scientists who studied their conversations in detail found that they take “fast-paced turns” when exchanging information and also occasionally interrupt each other.
The discovery suggests “deep evolutionary similarities.” [with humans] “How face-to-face conversations are structured matters,” Prof Kat Hovaiter, from the University of St Andrews, told BBC News.
Hobeiter, who studies primate communication, explains that this rapid speech is characteristic of human speech: “We all take about 200 milliseconds between speech pauses, but there are interesting little cultural differences. Some cultures are ‘fast talkers.'”
A millisecond is one thousandth of a second.
A 2009 linguistics study measured these differences and found that, on average, Japanese speakers took 7 milliseconds to respond, while Danish speakers took about 470 milliseconds to intervene.
By studying thousands of instances of communication between wild chimpanzees, Professor Hobeiter and his colleagues were able to measure the duration of the animals’ conversations.
“It’s amazing how close the timing is between chimpanzees and humans,” she said.
The timing of chimpanzee conversations was much more varied: “The intervals ranged from interrupting the signaller 1,600 milliseconds before finishing the gesture to taking 8,600 milliseconds to respond,” Prof Hobeiter explained.
“This may be because the chimpanzees were in a natural environment and therefore had a wider range of behaviours, sometimes interrupting each other and sometimes taking longer to react.”
Image source, Cat Hobby
As part of their investigation into the evolutionary origins of communication, researchers have spent decades observing and recording the behavior of five groups of wild chimpanzees living in the forests of Uganda and Tanzania.
They recorded and translated over 8,000 gestures from over 250 animals.
Lead researcher Dr Gal Badich, also from the University of St Andrews, explained that gestures allowed the chimpanzees to avoid conflict and cooperate with each other.
“So when one chimpanzee gestures to another that it wants food, the other chimpanzee responds by either giving it the food or, if it’s not very generous, by gesturing to go away.
“They might come to an agreement about how or where to groom, and that’s interesting, but it happens with just a few short, gestural exchanges.”
He said future research investigating communication in other primates, more distantly related to humans, could provide a more complete evolutionary understanding of why humans adopted this rapid-turn speech.
“This will be a great way to better understand when and why the rules of our conversation evolved,” he said.
