Chimpanzee's- Washoe

It is reported that Washoe could reliably use about 250 signs. For Washoe to be considered "reliable" on a sign, it had to be seen by 3 different observers in 3 separate spontaneous instances in the correct context and used appropriately. Following those observations, it had to be seen 30 days in a row to be added to her sign list.

Chinchilla Information