Chimpanzees and humans share more communication similarities than previously thought. A new study reveals that chimpanzees engage in rapid, back-and-forth gesturing, mirroring the conversational flow of human communication. This discovery suggests a shared evolutionary path between chimpanzee communication and human language development.
Researchers at the University of St Andrews have been studying chimpanzee gestures, but this study, unlike previous research focusing on individual gestures, explored how two chimpanzees communicate through gestural exchanges. By collaborating with other scientists, they gathered observational data from wild chimpanzees across five communities in East Africa.
Turn-Taking and Timing in Chimpanzee Communication
“This extensive collaborative effort allowed us to examine features of gesture exchanges across multiple chimpanzee groups for the first time,” explained lead author Gal Badihi, a research fellow at St Andrews.
The team analyzed over 8,500 gestures from 252 chimpanzees, finding that roughly 14% involved exchanges between two individuals. The pattern and pace of these exchanges closely resembled human conversation. Like humans taking turns speaking, chimpanzees take turns gesturing with minimal pause between turns. This rapid turn-taking, occurring within 100 to 300 milliseconds, is consistent across chimpanzee groups and human cultures. Interestingly, while all chimpanzee groups exhibited rapid turn-taking, some groups were slightly slower than others, mirroring the variation in conversational pace observed in different human societies.
Evolutionary Links Between Chimpanzee Gestures and Human Language
The study’s findings, published in Current Biology, suggest that some unspoken rules governing human language may have originated in a shared ancestral past with chimpanzees and potentially other animals.
“This demonstrates that complex, structured communication doesn’t require language,” Badihi noted. “Chimpanzee gestural communication and human language might have evolved along similar lines to arrive at this fast-paced communicative strategy.”
Differences and Future Research
While sharing similarities, chimpanzee communication differs significantly from human language. The rapid back-and-forth gesturing only accounts for a small percentage of their communication (14%), unlike its prevalence in human interaction. This suggests a different functional role for this communication style in chimpanzees. Researchers aim to investigate if this communication style exists in other ape species and beyond.
The research highlights a fascinating parallel between chimpanzee and human communication, offering valuable insights into the evolutionary roots of language. It reinforces the interconnectedness of the animal kingdom and the complex communication strategies that have evolved across species.
