Dr. Francine Patterson taught a modified form of sign language to Koko, a western lowland gorilla. Much media attention has been focused on Koko, especially after her death, and Patterson herself published several papers on Koko's use of language and cognition. I'm wondering if similar research has been performed with independent researchers and subjects. I am aware that Koko taught another gorilla Michael language, but he died in 2001.
- Have there been any experiments to replicate or test Patterson's publications, claims, and/or discoveries related to Koko's use of language and cognition?
- Has anyone compiled a study of these experiments' as a group?