Chimpanzees combine vocal calls to create new meanings, as in human language.
Science Editorial, May 9 (EFEverde).- Humans are the only species that uses language, but this ability may not be as unique as previously thought, as chimpanzees have a complex communication system that allows them to combine calls to create new meanings, similar to our language.
This newly discovered chimpanzee vocal system, documented in 53 wild specimens, could represent an evolutionary bridge between animal calls and human language, according to a study led by the Max Planck Institute (Germany) and published in Science Advances.
The team mathematically analyzed 4,323 recorded sounds from apes in the Taï Chimpanzee Project (Ivory Coast) and linked them to specific events: feeding, nesting, approaching, aggression, or encountering a predator.
Wild chimpanzees alter the meaning of individual calls when they combine them in various combinations, mirroring the linguistic operations of human language.
Our language combines sounds into words and words into phrases, creating infinite meanings, a process based on linguistic rules and with the key component of syntax, which determines how word order affects meaning,
Other primates tend to rely on single calls, and although some species combine them, these are rare and serve primarily to alert others to the presence of predators.
However, chimpanzees have four ways of altering meanings by joining individual calls into 16 combinations of two (bigrams), analogous to key linguistic principles of human language, to convey more meaning than would fit in a single one.
For example, nesting bigrams communicated information about where to build sleeping sites that were also safe from predators.
These findings “suggest a highly generative vocal communication system, unprecedented in the animal kingdom,” according to Cédric Girard-Buttoz, first author of the study.
Furthermore, it echoed recent findings in bonobos, which suggest that complex combinatorial abilities were already present in the common ancestor of humans and these two great ape species.
A study published a month ago by Science indicated that bonobos, our closest living relatives, are capable of creating complex combinations of calls with which they communicate and that are similar to the combinations of words used by humans.
These discoveries, Girad-Buttoz said, change the views of the last century, which considered that great ape communication was fixed, tied to emotional states, and therefore could not contribute anything to the evolution of language.
The communication system discovered in the new study has “important implications for understanding the evolution of human language,” notes Max Planck.
Complex combinatorial abilities may have been present in the common ancestor of humans and great apes, highlighting the need for further research into the complexity of animal communication and its relationship to human language, the authors say.
Drum and beatsA second study on chimpanzees, also published today in Current Biology, reveals that they drum with regular spacing between beats and with different rhythms depending on the group.
These findings suggest, according to the researchers, led by the University of Vienna, that the basic components of human musicality arose in a common ancestor of chimpanzees and humans.
Previous studies have shown that chimpanzees produce low-frequency sounds by drumming on large tree roots growing above the ground.
The team, which studied 371 taps across 11 chimpanzee communities, including six populations and two subspecies, saw clear differences in rhythm between them and found they shared distinct similarities with human music.
Researchers suggest that chimpanzees use these drumming patterns to transmit information over both long and short distances, and that each animal has its own unique style. EFE
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