Chimpanzees use Rapid Gestures, Much Like Human Conversations

When people converse, they quickly take turns speaking and sometimes interrupt each other. Researchers who have compiled the largest dataset of chimpanzee “conversations” have discovered that chimps also communicate using gestures in a similarly rapid manner. These findings, reported on July 22 in Current Biology, reveal that chimpanzees follow a rapid-fire pattern similar to human conversation.

“Human languages are incredibly diverse, but a common feature is the fast-paced turn-taking, averaging just 200 milliseconds,” said Catherine Hobaiter from the University of St Andrews, UK. “We previously wondered if this was unique to humans or if other animals also exhibit this conversational structure.”

“We discovered that chimpanzee gesture timing and human conversational turn-taking are both similar and extremely rapid, indicating that comparable evolutionary mechanisms may drive these social and communicative interactions,” says Gal Badihi, the study’s lead author.

Investigating Chimpanzee Communication Patterns

The researchers were aware that human conversations, regardless of culture or location, generally follow a rapid and structured pattern. They aimed to determine if chimpanzees, who use gestures rather than speech, exhibit a similar communicative structure. To investigate, they gathered data on chimpanzee “conversations” from five wild communities in East Africa.

In total, they analyzed over 8,500 gestures from 252 chimpanzees, measuring turn-taking timing and conversational patterns. They found that 14% of interactions involved gesture exchanges between two individuals, with most interactions comprising two-part exchanges, though some included up to seven parts.

Similarities in Gesture Timing

The data revealed that chimpanzee gesture timing closely resembles human conversation, with brief pauses of about 120 milliseconds between gestures and responses. However, behavioral responses to gestures were slower. “The parallels to human conversations highlight these interactions as genuine gestural exchanges, where gestures in response are contingent upon those from the previous turn,” the researchers write.

“We observed some variation among different chimpanzee communities, similar to the slight cultural differences in human conversation pace,” Badihi notes. “For instance, just as some cultures have faster or slower talkers, the Sonso community in Uganda exhibits slower responses compared to others.”

Hobaiter adds, “It’s intriguing that chimpanzees share both our universal timing and subtle cultural differences. For example, Danes are known for slower responses, akin to the Sonso community among Eastern chimpanzees.”

Shared Communication Rules

These similarities in face-to-face communication between humans and chimpanzees suggest shared underlying rules, potentially rooted in common ancestral mechanisms. The findings propose that human communication might not be as unique as previously thought, as both species may have developed similar strategies to coordinate interactions and manage communicative competition.

“It demonstrates that other social species can engage in close-range communicative exchanges with rapid response times even without language,” Badihi says. “This suggests that human conversations might share a similar evolutionary background or developmental path with the communication systems of other species, indicating that such communication is not unique to humans but more common among social animals.”

In future research, the team plans to investigate why chimpanzees use these conversational structures. They hypothesize that chimpanzees often use gestures to make requests from each other.

“We still don’t know when or why these conversational structures evolved,” Hobaiter says. “To answer that, we need to study communication in more distantly related species to determine if these traits are unique to apes or shared with other highly social animals, like elephants or ravens.”

Read the original article on: ScienceDaily

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