SIGN LANGUAGE AND COMPARATIVE COGNITION
Research around forms of communication beyond human language has produced important information about animal communication. In this sense, there are two linguistic laws that have been observed in species other than the human species. One of them is an indirect relationship between the length of words and the frequency of their use. This law has been observed in the communication, both oral and gestural, of different animals, in addition to the human being. On the other hand, there is another law which is based on the fact that the longest communication sequences are formed from shorter elements. After observing a group of chimpanzees, a team of researchers has been able to derive the first evidence that these laws are fulfilled in the gestural communication of these animals.
In addition to using gestures with their limbs, chimpanzees communicate with noises, facial gestures, and body postures. In this regard, according to the researchers, the gestures used by chimpanzees to communicate follow the same rules associated with human language.
Washoe, a chimpanzee born in the wild in West Africa in 1965, is the subject of an investigation at the University of Nevada, which aimed to teach Washoe American Sign Language. Washoe learned to identify sadness and express it in sign language, she knew how to lie or even apologize. The most surprising thing is that she transmitted American Sign Language from generation to generation: Washoe's son died a few days after birth, but they found an orphaned chimpanzee calf which she received with love.
In addition, the scientists also observed that, after learning sign language, other chimpanzees managed to have conversations with each other in that language. Washoe and sign language totally changed the way of understanding communication and even respect for the animal world.