Words and pictures: use of symbolism by two lowland gorillas
A female western lowland gorilla (Gorilla g. gorilla)
named Koko began to learn American Sign Language (ASL) 27 years ago. Michael, a male
western lowland, joined the project three years later. Both gorillas were taught sign
language through a combination of modeling, molding, and imitation, frequently in
combination with spoken English. Koko's acquisition and use of sign language almost
immediately exceeded expectations. Her vocabulary development showed remarkable parallels
to that of human children, both in pattern and in content (Bonvillian and Patterson, 1999;
Patterson, 1978; Patterson and Cohn, 1991; Patterson, Tanner and Mayer, 1988). She has
exhibited the hallmarks of human language use, for example, productivity, displacement,
and transmission (Hockett, 1960; Patterson, 1978). Both gorillas are able to translate
spoken words into sign, and can respond in sign to spoken questions. Recent, more detailed
analysis of the structure of Koko and Michael's multiple-sign combinations
("sentences") is revealing consistencies indicative of grammatical rules
(Patterson, et al, in preparation). In this talk, I will review Koko's cognitive and
language development, and introduce some comparisons with that of Michael, who began
learning sign language later in his childhood than did Koko. I will discuss plans for
further analysis of the gorillas' language and related symbolic abilities. Finally, I will
consider how these findings can shape and inform our understanding of our human selves.
Bonvillian, J.D., and Patterson, F.G.P. (1999) Early sign-language acquisition:
comparisons between children and gorillas. In S. Taylor Parker, R.W. Mitchell, and H. Lyn
Miles (eds.), The mentalities of gorillas and orangutans (pp. 240-264). Cambridge
Hockett, C.F. (1960). The origin of speech. Scientific American, 203, 88-96.
Patterson, F. (1978). Linguistic capabilities of a lowland gorilla. In F.C.C. Peng (Ed.),
Sign Language acquisition in man and ape: New dimensions in comparative psycholinguistics.
Boulder, CO: Westview Press.
Patterson, F., Tanner, J. and Mayer, N. (1988). Pragmatic analysis of gorilla utterances:
Early communicative development in the gorilla Koko. Journal of Pragmatics, 12, 35-54.
Patterson, F.G.P., Cohn, R.H. (1991). Language acquisition by a lowland gorilla: Koko's
first ten years of vocabulary development. Word, 41(2), 97-144.