When humans converse, they quickly exchange turns, often interrupting each other. Recent research, which compiles the largest dataset of chimpanzee ‘dialogues’ to date, has revealed that these primates also engage in back-and-forth communication using gestures in a similarly rapid manner.
When humans converse, they quickly exchange turns, sometimes interrupting each other. Recent research has compiled the largest dataset of chimpanzee “dialogues” to date, showing that these primates also communicate back and forth with gestures in a similarly rapid manner. The findings were published on July 22 in the journal Current Biology.
“Despite the great diversity in human languages, one common feature is our fast-paced conversational exchanges, averaging just 200 milliseconds per turn,” stated Catherine Hobaiter from the University of St Andrews, UK. “But it remained unclear whether this was a unique trait of humans or if other species might share this characteristic.”
“Our research indicates that the timing of gestures in chimpanzees mirrors that of human conversational turns, exhibiting a rapid pace that implies similar evolutionary processes are at play in these social and communicative interactions,” explained Gal Badihi, the study’s lead author.
The researchers recognized that the structure of human conversations is consistent among diverse cultures worldwide. They aimed to determine if this same structure exists in chimpanzee communication, which relies on gestures instead of spoken language. To investigate this, they gathered data on ‘conversational’ gestures from five wild chimpanzee communities in East Africa.
In total, they documented over 8,500 gestures from 252 chimpanzees, examining the timing of turn-taking and communication patterns. They discovered that 14% of the interactions included a two-way exchange of gestures, with most comprising two parts and some extending up to seven parts.
The results showed a timing pattern comparable to human conversation, with brief pauses of about 120 milliseconds between a gesture and its response. The response times to gestures were generally slower. “The similarities to human discourse strengthen the notion of these being genuine gestural exchanges, where each gesture responds to the preceding one,” the researchers noted.
“We observed some variations among different chimpanzee communities, which aligns with the variations seen in human cultures regarding conversation speed: some cultures tend to speak more slowly or quickly,” Badihi remarked.
“Interestingly, they seem to exhibit our universal timing along with subtle cultural nuances,” Hobaiter stated. “For humans, Danish speakers are typically ‘slower’ responders, while in Eastern chimpanzees, this trait is seen in the Sonso community of Uganda.”
This similarity in communication styles between humans and chimpanzees suggests shared foundational rules in how they interact, the researchers pointed out. They propose that these structures may stem from common ancestral communication methods. It’s also conceivable that both species developed analogous strategies to facilitate interaction and manage competition for communicative opportunities. These findings imply that human communication may not be as distinctive as once believed.
“This indicates that other social species can engage in rapid, close-range communicative exchanges without needing language,” Badihi observed. “Human conversational patterns may share evolutionary roots with the communication systems of other social animals, highlighting that this form of interaction is not exclusive to humans but is more prevalent among social species.”
For future research, the team hopes to investigate the reasons behind chimpanzee conversations. They theorize that chimps often use gestures to communicate requests to each other.
“We still lack clarity on when these conversational patterns emerged, or what triggers them!” Hobaiter admitted. “To address this question, we will need to examine communication among more distantly related species — helping us determine whether these traits are unique to apes or shared with other highly social animals like elephants or ravens.”
