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Like humans, wild chimpanzees engage in rapid conversations, waiting a fraction of a second for their turn to “speak.”
Animals communicate mostly through gestures including hand movements and facial expressions.
Scientists who studied their conversations in detail found that they took “quick turns” when exchanging information, and sometimes interrupted each other.
The discovery points to “deep evolutionary similarities.” [with humans] “There are differences between cultures in how face-to-face conversations are structured,” Professor Kat Hoppeter from the University of St Andrews told BBC News.
Professor Hopper, who studies primate communication, explained that this rapid turn-taking is a hallmark of human conversation. “We all take about 200 milliseconds between turns, and we show some interesting little cultural differences. Some cultures speak very quickly,” he said.
A millisecond is one thousandth of a second.
A 2009 linguistic study measured the timing of these differences — showing that on average, Japanese speakers took seven milliseconds to respond while Danish speakers took about 470 milliseconds to intervene.
By examining thousands of instances of wild chimpanzees communicating with each other, Professor Hopper and her colleagues were able to pinpoint the timing of conversations between the animals.
“It’s amazing to see how close the timings are between chimpanzees and humans,” she said.
Chimpanzees had a wider range of conversational timings. “The gaps ranged from the sender interrupting for 1,600 milliseconds before ending the audio signal, to taking 8,600 milliseconds to respond,” Professor Hobaiter explained.
“This may be because the chimpanzees were in a natural environment, and therefore were able to express a wider range of behaviour – sometimes interrupting each other and other times taking longer to respond.”
Image source, Hobby cat
As part of an investigation into the evolutionary origins of communication, the researchers spent decades observing and recording the behavior of five communities of wild chimpanzees in the forests of Uganda and Tanzania.
They recorded and translated over 8,000 signals from more than 250 individual animals.
Lead researcher Dr Gal Badihi, also from the University of St Andrews, explained that the gestures allowed chimpanzees to avoid conflict and coordinate with each other.
“Thus, one chimpanzee might signal to the other that he wants food, and the other might offer him food, or if he feels less generous, might respond by signaling to leave.
“They may come to an agreement on how or where to take care of the pet. It’s a wonderful thing, and it’s done with a few short nods.”
Future studies looking at communication among other distantly related primate species will give us a more complete evolutionary picture of why we adopted this rapid conversation, he said.
“This would be a great way to understand when and why our conversational grammar evolved,” he said.
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