In 1966,Allen and Beatrice Garden, two professors at the University of Nevada in Reno, had a bright idea.They were interested in the evolution of language and the language abilities of great apes  . Previous attempts to teach chimpanzees  to talk had ended in failure and the matter was considered by most people to be closed. But the Gardens realized that speech and the language are not the same thing. Many deaf people, for example, are unable to speak but are perfectly able to communicate by gestures that have all the features of spoken language. The Garders suspected that previous experiments had failed because chimpanzees are physically unable to speak.    They therefore decided to try teaching a chimpanzee to sign in the way that deaf people do. And their chosen  _ , a female chimpanzee named Washoe after the country in which the university is, proved to be a skillful pupil. Though there is still debate about whether what Washoe learned was really equal to human language, there is no doubt that she learned a lot of words. All of this, however, raises a second question. If Washoe can learn a complex vocabulary of gestures from people, do they have such vocabularies naturally ? To examine that possibility, Amy Pollick and Frans de Waal of Emory University have looked at gestures and expressions in chimpanzees,    Signaling by facial and oral expressions is common among primates  . Signaling by gestures is limited to great apes. The researchers supposed that the meaning of expressions has been fixed by evolution while the meaning of gestures is learnt. If that were true, particular sorts of facial and oral expressions would occur only in particular circumstances, and this would be the same across groups and even species. The same gestures, on the contrary, would be used in different circumstances. The researchers found exactly what they expected. Expressions almost always occurred in the same circumstances in different groups and different species. Gestures seemed to have completely different meanings. Moreover, even within a single group,the meaning of a gesture could vary with circumstances. It's also worth remembering that gesture is still an essential part of human language, even for those with normal hearing. The old joke that the way to make an Italian speechless is to tie his hands together has much truth in it. Evolution does not come up with complex structures in a single leap. They are built up step by step. This study suggests that the step of speech may have been built on mental features that were acquired millions of years ago when the ancestors of apes and men began to wave meaningfully at each other. What does the research carried out by Amy Pollick and Frans de Waal probably indicate ?
Human speech may develop from gestures The apes are the closest species to human beings Normal people do not really need the help of gestures Gesture is not part of human language