I've heard that the evidence that chimps were using sign language to express thoughts and feelings is now thought to have been largely wishful thinking by the researchers. Apparently when they brought in other people who knew sign language, they didn't see nearly as many clear "signs" as the researchers were. This is a really common problem in animal intelligence research.
I've heard that the evidence that chimps were using sign language to express thoughts and feelings is now thought to have been largely wishful thinking by the researchers. Apparently when they brought in other people who knew sign language, they didn't see nearly as many clear "signs" as the researchers were. This is a really common problem in animal intelligence research.