What Did Language Grow From? Ape Hands, Mouths, or Both?

Did language grow from gestures? That is, was using the hands, arms, or head to communicate a step toward the development of language? We studied gestures and symbols used by a chimpanzee, a bonobo, and a human child who were all taught to use symbols. A symbol can be visual or spoken; the important thing is that it means something. The apes’ symbols were pictures called lexigrams; the child’s symbols were spoken words. The chimpanzee, bonobo, and human child used many of the same gestures. They used gestures when they were young and later added symbols. The child used her voice while gesturing more than the apes did. Our study shows that the ancestor of humans, chimpanzees and bonobos probably used gestures to communicate. Our study also shows that putting sounds and gestures together was an important skill that early humans could build on to create language over thousands of years.