I emailed Tim Sandefur after I spotted some critical comments on his blog about Koko. He has responded the email.
My primary concern is that the interpreters are biased, either because they are looking too hard, or because they see what they want to see, or because of something else. A person who knows sign language would be at least equally susceptible to such a bias as a person who does not, and perhaps moreso.
The problem with the position is that skeptics have often reviewed Koko’s abilities. My understanding is that not a single skeptic of Koko, who has actually interacted with her, doubts her reported abilities. Sandefur’s concerns are based on an incomplete knowledge about the research involving Koko and the other signing gorillas.
There is a wealth of knowledge about the research with Koko on IIDB because one of the posters, Biff the Unclean, works with her and has participated in long threads about the research, answering questions and responding to critics.
I once asked Biff to ask Koko if humans are apes. Her response was that we aren’t pretty enough to be apes.
