Research into chimpanzees finds that the primates combine calls to form numerous vocal sequences, indicating further step in understanding the sophisticated language of chimpanzees.
At the first level, how animals communicate with each other appears quite simple. Yet also remains an area of uncertainty as to how our language evolved from such a simple system.
Scientists at the Max Planck Institute for Evolutionary Anthropology report on how they have found evidence of structured vocal sequences in wild chimpanzee communication. Not only does this advance undemanding about chimpanzees, it also provides insights into human language evolution.
People communicate using hierarchically structured sentences, yet where this capacity originates from, is unknown. Clues as to the evolutionary origins of human language are commonly sought using a comparative approach, such as studying the vocal production of other animals.
The research revealed that the animals produced hundreds of different vocal sequences containing up to ten different call types. The order of calls in these sequences followed some rules, and calls were associated with each other in a structured manner.
The next wave of research considers if this structure may constitute a step towards human syntax and if chimpanzees use these sequences to communicate a wider range of meanings in their complex social environment.
Human communication is complex and this derives from the way people combine sounds in a structured manner to form words and hierarchically combine these words to form sentences to express an infinite number of meanings.
The researchers recorded thousands of vocalisations produced by the members of three groups of wild chimpanzees in the Taï National Park in Ivory Coast. From these they identified 12 different call types and assessed how chimpanzees combine them to form vocal sequences. This revealed a previously undiscovered complexity in terms of communication.
Furthermore, chimpanzees communicate with each other using hundreds of different sequences, combining up to ten call types across the whole repertoire. Calls occur in certain positions in the sequence, following adjacency rules. These adjacency rules applied also to sequences with three call types.
It is hoped that further explorations of chimpanzee communication will boost our understanding where we come from and how our unique language evolved. This will arise from further study into understanding what the complex and structured vocal sequences of chimpanzees mean and whether these variances enable allow chimpanzees to increase the range of topics they can communicate about.
The research appears in the journal Communications Biology, titled “Chimpanzees produce diverse vocal sequences with ordered and recombinatorial properties.”
