📰 Chimpanzees use many structured voice sequences to communicate

© Liran Samuni / Tai Chimpanzee Project

The question of the evolutionary origins of our language from much more simplified forms of communication in animals remains unresolved. A study, published in the journal Communications Biology, reveals an unsuspected flexibility in the communication (Communication concerns both man (intra-psychic, interpersonal communication, etc.) chimpanzees that use hundreds of voice sequences. The different calls in these sequences follow one another in a structured way. It remains to be established whether these sequences carry a sense (SENS (Strategies for Engineered Negligible Senescence) is a scientific project which aims to…) differ from that of calls produced alone.

Humans are the only species (In the life sciences, the species (from the Latin species, « type »…) on earth (Earth is the third planet in the Solar System in order of distance…) able to use language. The language is characterized by a combination (A combination can be:) of sounds into words which are then recombined in a hierarchical and structured way to form sentences. The question of the origins of this unique human ability remains wide open. The comparative method is often used to trace the evolutionary origins of language. This method consists in comparing the vocal production of animals and in particular of primates (The primates (from the Latin primas, atis meaning « the one who occupies the first…) non-humans, to that of themale (A man is an adult male individual of the species called Modern Man (Homo…). Unlike humans, other primates very rarely combine the different types of calls that form their vocal repertoire to form vocal sequences and the diversity of sequences produced remains limited.

This difference is important. Indeed, what makes the specificity of language does not reside in the number (The notion of number in linguistics is treated in the article « Number…) of sounds that we use, which remains around (Autour is the name that the avian nomenclature in the French language (update) gives…) of 50 sounds in mean (The average is a statistical measure characterizing the elements of a set of…) by language, but in our ability to combine these sounds to form words and to use these words in structured sentences that allow us to communicate a number infinite (The word « infinity » (-e, -s; from the Latin finitus,…) of meaning. Non-human primates also use up to 38 sounds (types of cries) different to communicate, but studies show that they very rarely recombine them. However, is this ability to produce vocal sequences really so limited as seen so far or is the paucity of studies documenting vocal sequences in non-human primates related to a lack of effort to research (Scientific research designates in the first place all the actions undertaken with a view to…) ?

To find out, scientists recorded thousands of vocalizations produced by members of three groups of wild chimpanzees within the Park (A Park is an enclosed natural land,[1] formed of woods or meadows, in which were…) National of Taï in Ivory Coast. They identified 12 different types of calls and analyzed how these calls were combined into vocal sequences. Studying the structure of these vocal sequences is important to trace the evolution of language since syntax is one of the key aspects of language. The study showed that chimpanzees use hundreds of different vocal sequences, combining up to 8 different types of calls. This is the first time that such diversity has been documented in a non-human primate species. In addition, the researchers were able to demonstrate that these vocal sequences are structured since the different calls that compose them have a determined position in the sequence and associations of stable arrangement with the preceding and following calls.

These results highlight light (Light is the set of electromagnetic waves visible to the eye…) a complex voice communication system in one of our closest cousins, the chimpanzee (The term chimpanzee today refers to two species of great apes that form the…), which allows flexibility in their communication despite a limited vocal repertoire. It now remains to be determined whether these vocal sequences allow chimpanzees to extend their ability to communicate about different aspects of their life (Life is the name given 🙂 social or if these sequences are a simple juxtaposition of the meaning that is carried by each of the cries that compose them.

Illustration in the form of a network of the diversity of combinations between types of calls in the vocal sequences of chimpanzees as well as an example of a vocal sequence combining a simple call (the pant-bark) and a pair (We say that a set E is a pair when it is formed of two distinct elements…) of cries (pant-grunt + grunt) in a longer sequence.
© Cedric Girard-Buttoz

To know more:
Chimpanzees produce diverse vocal sequences with ordered and recombinatorial properties Cédric Girard-Buttoz, Emiliano Zaccarella, Tatiana Bortolato, Angela D. Friederici.
Roman M. Wittig & Catherine Crockford /
Communications Biology. May 16, 2022 http://nature.com/articles/s42003-022-03350-8.

Laboratory:
Institute of Cognitive Sciences Marc Jeannerod (CNRS/Lyon 1 University) – 67 Boulevard (In the first sense, a boulevard is a communication route resting on old ramparts,…) pinel. 69675 BRON Cedex.

Contact:
Cédric Girard-Buttoz – Post-doctoral fellow at theInstitute (An institute is a permanent organization created for a certain purpose. It is…) of cognitive sciences Marc Jeannerod (CNRS/Lyon 1 University) – Cedric at buttoz.com