Transfer of signed responses in American Sign Language from vocal English stimuli to physical object stimuli by a chimpanzee (Pan)

A chimpanzee was taught 10 signs of Ameslan (American Sign Language) using only vocal English words as stimuli. The corresponding physical objects were items found in the subject's home environment, and which he frequently encountered during daily activities. Reference was not made to these items during teaching sessions. Each teaching session was followed by a test session in which the objects were silently presented to the subject and the question What that? was signed to him. The subject acquired all 10 signs in response to the English word stimuli and then successfully transferred these signs to their physical object referents during testing.