Washoe is a chimpanzee, now (2003) living at the Chimpanzee and Human Communication Institute (CHCI) at Central Washington University in Ellensburg, Washington. She was the first non-human to acquire at least some elements of American Sign Language (ASL). She was named for Washoe County, Nevada, where she was raised and taught to use ASL.

In 1967, Allen and Beatrice Gardner established a project to teach Washoe ASL. Previous attempts to teach chimpanzees vocal languages had failed. The Gardners based their approach on the intuition that previous projects had failed because observations chimpanzees' vocal apparatus is somewhat limited, not because they are inherently unable to learn language. They chose ASL as a vehicle for their study because they noted that chimpanzees spontaneously use bodily gestures in communication in flexible ways. Like the chimpanzees in previous studies, Washoe was raised in a language-rich environment (in her case, a sign language-rich environment) that was designed to mimic that of a human child in many ways.

Like many other studies involving attempts to teach language or language like behaviour to apes, the Washoe project has been highly controversial, and different authors make wildly conflicting claims about its success. However, peer-reviewed research papers, and widely circulated film records, show beyond reasonable doubt that under the Gardners' instruction programme, Washoe did succeed in:

  • learning several signs
  • responding to a range of instructions given in ASL
  • making requests in ASL.

More controversial are the claims that Washoe
  • combined ASL signs in innovative ways. One or two striking examples are well documented, but only one or two.
  • attempted to use ASL to communicate with other apes
  • taught another chimp, Loulis, to use ASL.

The latter two claims have not yet been backed up by peer-reviewed scientific research papers. However, the intriguing report that Washoe passed on ASL to another chimpanzee has helped nourish interest in chimpanzee culture. There are other independent lines of evidence for cultural transmission of behaviour in animals especially primates.

Critics of the Washoe project have argued that

  • Behaviour like hers can be produced by standard operant conditioning techniques. This claim is particularly associated with Herbert S. Terrace.
  • The signs she made were impoverished in comparison with human ASL.
  • Her signing behaviour lacks a key dimension present in human language from a very early age, namely enquiring after new information.

Resolution of these controversies will probably only come about through repeated attempts to replicate the training given to Washoe. A number of other projects have sought to establish ASL or other forms of language in other chimpanzees and also in gorillas and bonobos, as well as in non-primate species such as dolphins, woodpeckers and parrots (specifically, an African Grey Parrot). A clear view of the potential and limitation of other species' use of human languages is likely to come from an integration of the results of all these projects, rather than an essentially historical pursuit of what did or did not happen in Project Washoe. However the Washoe project will remain important as the first publicly accepted success in teaching language to an animal of another species, and thus the stimulus for virtually all the projects that have followed it.