Experiment on Chimpanzees

The mid-sixties saw the start of a project that, along with other similar research, was to teach us a great deal about the chimpanzee mind. This was Project Washoe, conceived by Trixie and Allen Gardner. They purchased an infant chimpanzee and began to teach her the signs of ASL, the American Sign Language used by the deaf. Twenty years earlier another husband and wife team, Richard and Cathy Hayes, had tried, with an almost total lack of success, to teach a young chimp, Vikki, to talk. The Hayes' undertaking taught us a lot about the chimpanzee mind, but Vikki, although she did well in IQ tests, and was clearly an intelligent youngster, could not learn human speech. The Gardners, however achieved spectacular success with their pupil, Washoe. Not only did she learn signs easily, but she quickly began stringing them together in meaningful ways. It was clear that each sign evoked, in her mind, a mental image of the object it represented. If, for example, she was asked, in sign language, to fetch an apple, she would go and locate an apple that was out of sight in another room.

Other chimps enter the project, some starting their lives in deaf signing families before joining Washoe. And finally Washoe adopted an infant, Loulis. He came from a lab where no thought of teaching signs had ever penetrated. When he was with Washoe he was given no lessons in language acquisition—not by humans, anyway. Yet by the time he was eight years old he had made fifty-eight signs in their correct contexts. How did he learn them? Mostly, it seems, by imitating the behavior of Washoe and the other three signing chimps, Dar, Moja and Tatu. Sometimes, though he received tuition from Washoe herself. One day, for example, she began to swagger about bipedally, hair brisling, signing "food! food! food!" in great excitement. She had seen a human approaching with a bar of chocolate. Loulis, only eighteen months old, watched passively. Suddenly Washoe stopped her swaggering, went over to him, took his hand, and molded the sign for food (fingers pointing towards mouth). Another time, in a similar context, she made the sign for chewing gum—but with her hand on his body. On a third occasion Washoe picked up a small chair, took it over to Loulis, set it down in front of him, and very distinctly made the chair sign three times, watching him closely as she did so. The two food signs became incorporated into Loulis' vocabulary but the sign for chair did not. Obviously the priorities of a young chimp are similar to those of a human child!