Naming others is considered a sign of cognition very advanced in social animals, previously observed only in humans, dolphins and African elephants.
Marmoset monkeys have now joined this exclusive club, according to a new study published in the journal Science on Thursday.
The tiny primates They use loud, high-pitched calls to assign “vocal labels” to each otheras shown in the research, conducted by a team at the Hebrew University of Jerusalem.
“We are very interested in social behavior because we believe that It is what essentially led humans to be so special compared to other animals.“The study’s lead author, David Omer, told AFP.
“We don’t run fast, we don’t fly, we don’t excel at anything other than being social, and all of our achievements as a society are our social achievements,” he said.
Marmosets are ideal subjects for studying the evolution of social behavior and language in humans, he explained, because they display similar traits and live in small, monogamous family groups of six to eight individuals that raise their offspring cooperatively.
Led by graduate student Guy Oren, Researchers recorded natural conversations between pairs of marmosets separated by a visual barrier.as well as interactions between the monkeys and a computer system that played pre-recorded calls.
They discovered that these animals use “phee calls” (high-pitched vocalizations, as loud as power tools) to address each other.
In particular, they could recognize when such calls were directed at them and were more likely to respond when called by name.
Advances in machine learning
The ten marmosets used for testing came from three different families, and the research also revealed that Members of a family group used the same sound characteristics to encode different names similar to human dialects or accents.
This was true even for adult individuals that were not related by blood, suggesting that they learned from others within the family group.
Marmoset monkeys are relatively distant relatives of humans. The last time they shared an ancestor was about 35 million years ago.while the split between humans and chimpanzees may have occurred between 5 and 7 million years ago.
Rather than genetic proximity, Omer attributes the marmosets’ acquisition of vocal tags to “convergent evolution,” or the idea that they developed similar traits in response to comparable environmental challenges.
For these primates, vocal tagging may have been crucial to maintaining social bonds and group cohesion in the dense rainforests of South America, where visibility is often limited.
How and when humans began to speak is a matter of debate, but until recently many scientists had dismissed the idea that clues could be found in other primates.
“We can still learn a lot from nonhuman primates about the evolution of language in humans,” Omer said.
The analysis of marmoset calls was made possible by recent advances in computing power and machine learning.he added.
Looking ahead, an interesting avenue for future research could be to leverage AI to better decipher the content of these peculiar conversations.