A new study has challenged long-held assumptions about what makes human communication unique. Researchers at Harvard and the University of Zurich found that bonobos, our closest living relatives, create complex vocal combinations similar to human language. The study, conducted on wild bonobos in the Democratic Republic of Congo, used novel methods from linguistics to demonstrate that compositionality – the ability to combine meaningful words into phrases with related meanings – is a shared trait between humans and bonobos.
Compositionality has two forms: trivial and nontrivial. Trivial compositionality involves combining parts to create a new whole, like “blond dancer” referring to someone who is both blond and a dancer. Nontrivial compositionality, on the other hand, involves one part modifying another, such as “bad dancer” not referring to a bad person who is also a dancer.
The researchers created a bonobo dictionary by applying a method developed by linguists to quantify the meaning of human words. This allowed them to understand the meaning of single bonobo vocalizations and call combinations. The study found numerous call combinations that resemble complex nontrivial compositional structures in human language, suggesting that the ability to combine call types in complex ways is not unique to humans.
The research has significant implications for our understanding of the evolutionary roots of language’s compositional nature. Since humans and bonobos share a common ancestor around 7-13 million years ago, it’s likely that compositionality was already used by our ancestors. The findings indicate that the ability to construct complex meanings from smaller vocal units existed long before human language emerged, and that bonobo vocal communication shares more similarities with human language than previously thought.
Source: https://www.goodnewsnetwork.org/bonobos-communicate-in-complex-phrases-a-language-process-once-thought-unique-to-humans