You can summarize yourself.
Humans have probably always recognized a family resemblance in the great apes. The name we use for the great tree-dwelling, red-haired apes of Borneo comes from the Indonesian “orang,” person, and “hutan,” jungle. Some people have kept young chimps as pets. Many less wealthy people have owned plush toy chimps to cuddle at night. The famous chimpanzee researcher Jane Goodall traces her fascination with chimpanzees to a toy chimp named Jubilee, which she kept for decades.
At the same time, we have sought to distance ourselves from the beasts, often using language as the defining difference. In the first century b.c., Roman historian Sallust wrote “All men who would surpass the other animals should do their best not to pass through life silently like the beasts.” In the 1600s, Descartes found a universal human truth in “I think, therefore I am.” But animals, Decartes declared, didn’t think; they were mere automata, beast machines. Descartes’ follower, La Mettrie, however, pointed out that deaf humans have a difficult time learning to speak and guessed that with the right teacher, a chimpanzee could learn and thereby become “a little gentleman.”
This schizophrenic attitude persists today. No reputable scientist disputes Darwin’s assertion of physical continuity from the simplest animals to humans, and the great apes clearly share much with humans. Their anatomy and their genome resembles ours more than any other organism, and even their brains have similar—though smaller—parts. If researchers could emulate the fictional Dr. Doolittle and converse with an animal, surely that animal would be a great ape. On the other hand, some scientists insist that the resemblance ends at language. Despite a continuity of other traits, they say, language stands alone, not merely the most complicated kind of communication, but a unique one, unrelated to that of any non-human animal.
Early attempts, from the 1900s through the 1930s, to teach chimps to speak met with dismal failure, vindicating the critics. The animals just couldn’t wrap their otherwise expressive lips around words. In the most successful cases, they made sounds charitably interpreted as short words, such as mama, papa, cup and up, after years of training.
Following La Mettrie’s suggestion that a gifted teacher of the deaf could succeed with chimpanzees, a 1925 scientific article suggested sign language as an alternative. But serious efforts to teach non-vocal communication to apes only began in the 1960s. Researchers attempted to teach individual signs derived from American Sign Language (ASL) to Washoe, a chimpanzee; Koko, a gorilla; and Chantek, an orangutan. Sarah, a chimpanzee, learned to manipulate arbitrary plastic symbols standing for words, and another chimpanzee, named Lana, used an early computer keyboard, with arbitrary symbols the researchers called lexigrams.
All these projects succeeded where the early speech projects had failed. The apes learned to use hand gestures, plastic symbols or keyboards to communicate with their trainers. The 1960s and 1970s became the golden age of ape language-learning. Researchers claimed (and some continue to claim) that the apes had learned tens or even hundreds of signs.
But popular accounts went farther. They had it that the apes held conversations, and had “learned sign language.” To this day, assertions that apes can converse with humans using symbols or sign language abound in popular magazines and books and even college textbooks. But although the trained apes often used two or three signs or symbols in a sequence, and could clearly get a message across—most often a request for food or attention—researchers wondered if the apes had learned Language with a capital L. Some researchers working in the field feel justified in using the word “language” to describe the results of these experiments, but psychologist Steven Pinker, author of The Language Instinct, disagrees.
Pinker has declared on public radio “No chimpanzee has learned sign language. ... They’ve certainly learned some gestures, but sign language is not just a system of gestures. It’s a full, grammatical language with its own systematic grammar, like Latin.”
Setting the idea of a full language aside, however, did the apes’ hand gestures constitute words? Did they truly understand that signs or lexigrams stood for objects or actions? Were their strings of two or three signs sentences?
