american scientists have found strong evidence to suggest various levels of gesticulations preceded human language as means of communication. A team at the Yerke Primate Center at Emory University in Atlanta, Georgia studied gesticulations, facial and vocal expressions of chimpanzees and their smalled cousins bonobos to establish levels of communication.
Lead researcher Amy Pollick told Down To Earth, "The fact that hand gesturing is universal in humans led us to suspect that there might be an evolutionary history to the behaviour. Also, we noticed that only apes and not monkeys gestured, suggesting that gesture might be more recent, evolutionarily, than other forms of communication."
Their study focused on 13 bonobos divided in two groups and 34 chimpanzees in two groups. From these groups the researchers distinguished 31 manual gestures compared with only 18 facial and vocal communications. The researchers also found that bonobos showed greater flexibility in their use of gestures than the chimpanzees and were also the only species in which multimodal communication--combination of gestures and facial or vocal signals--added to the communicative message.
They used the same gestures for different meanings. "A chimpanzee may stretch out an open hand to another as a signal for support, whereas the same gesture toward a possessor of food signals a desire to share," said Pollick. "A scream, however, is a typical response for victims of intimidation, threat or attack in both bonobos and chimpanzees. This suggests vocal signals have less variation," she said.
The team supports the 'gestural origins of language' theory, which suggests that our ancestors may have used gesture to communicate linguistically before they used speech for language. Evidence suggests that our brains were "language-ready" before our vocal chords.
Further evidence supporting this theory comes from neuropsychological researcher Michael Corballis at the University of Auckland, New Zealand. "The area in the ape brain responsible for gestures is similar to the area in the human brain responsible for language," he says. Hence, the combination of neurology and behaviour has convinced Pollick's team that gesticulations evolved into human language.
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