“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.”
I haven’t read much about the whole Koko situation, but my understanding is that part of the claim was that Koko was *unusually* adept with language.
A priori, if language comes “packaged for free” with some other high order cognitive functionalities that for whatever reason can only be maintained in a small proportion of chimps (maybe calorie availability, increased risk taking behaviour or something else), then it seems perfectly plausible that the capability for language would be present in some proportion of chimps >0 but below the critical threshold for language formation.
Alternatively, it also seems possible that the process of creating grammar is more difficult than the process of producing language in an already constructed grammar. In this case you could have a pretty high proportion of animals capable of producing language after instruction, but incapable of inventing language.
“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.”
I haven’t read much about the whole Koko situation, but my understanding is that part of the claim was that Koko was *unusually* adept with language.
A priori, if language comes “packaged for free” with some other high order cognitive functionalities that for whatever reason can only be maintained in a small proportion of chimps (maybe calorie availability, increased risk taking behaviour or something else), then it seems perfectly plausible that the capability for language would be present in some proportion of chimps >0 but below the critical threshold for language formation.
Alternatively, it also seems possible that the process of creating grammar is more difficult than the process of producing language in an already constructed grammar. In this case you could have a pretty high proportion of animals capable of producing language after instruction, but incapable of inventing language.