Conversely, if gorillas and chimps were capable of learning complex sign language for communication, we’d expect them to evolve/culturally develop such a language.
We’ve seen an extreme counterexample with octopi, which can be taught some very impressive skills that they don’t pick up in nature because they aren’t sufficiently social to develop them over the course of multiple generations. I think it’s within reason that gorillas could have the ability to learn more complex language than they use, so long as it’s not economical for them to spend time teaching their offspring those complexities as opposed to teaching them other things.
I will say that I’m very skeptical of Koko, though, for other reasons.
We’ve seen an extreme counterexample with octopi, which can be taught some very impressive skills that they don’t pick up in nature because they aren’t sufficiently social to develop them over the course of multiple generations. I think it’s within reason that gorillas could have the ability to learn more complex language than they use, so long as it’s not economical for them to spend time teaching their offspring those complexities as opposed to teaching them other things.
I will say that I’m very skeptical of Koko, though, for other reasons.