Ape And Human Babies Use Similar Gestures, Study Finds
Ape and human infants of comparable developmental ages use similar gestures, new research suggests.
Human, chimpanzee and bonobo a babies use gestures when they're about a year old. As they grow, they all gradually develop symbolic language. In humans, that means developing the ability to speak. In apes, it means using signs to communicate.
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"It's a new kind of evidence in favor of the gestural origins of language, and it's also a new kind of evidence in favor of the co-evolution of gesture and speech," said Patricia Greenfield, one of the study's authors and a psychology professor at the University of California at Los Angeles.
Greenfield says the similarities in the gestures among humans, chimps and bonobos is evidence that humans and apes used similar systems of communication six million years ago. If you go that far back, the researchers say, that's when humans inherited a language of gestures and the ability to learn symbolic language, from the same ancestor shared by chimpanzees and bonobos.
In the study, researchers observed a chimp, a bonobo and a young girl for over a year. GN, as the girl is called in the study, was observed in her home from the age of 8.5 months to about 2 years. The chimp, named Panpanzee, and the bonobo, Panbanisha, were observed by the team over the course of four years, at the Language Research Center in Atlanta. Researchers began observing the chimp and bonobo when they were about a year old, and concluded when they were 26 months old.
The researchers found that all three species made similar gestures to communicate the same things. They pointed to things to call attention to them, or to indicate that they wanted to go somewhere. When they wanted to be picked up, they raised their arms.
Like most human children, as GN grew she began vocalizing more, first with noises and eventually with words. The apes learned to communicate by pointing at lexigrams, a list of abstract symbols.
"Lexigrams were learned, as human language is, during meaningful social interactions, not from behavioral training," said head of the research team Kristen Gillespie-Lynch, a psychologist at City University of New York.
"The story that gesture was present in our common ancestors because of the similarities we see--that just hits you," Greenfield told NBC News.
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