I noticed a video by someone else trying to train his cats to communicate via buttons:
www.youtube.com/watch?v=02n6fWBFaTU&ab_channel=NeuroTransmissions
His conclusion is that there's no language learning going on. The cats are just randomly pressing buttons sometimes and humans are seeing patterns that aren't there. He also references Nim the signing chimp, where the researcher back pedalled significantly on his initial claims of language acquisition, after reviewing his data. There's a good documentary about this project.
One of the YT comments on Billi says "I believe when Billie's mom thinks she's confusing buttons repeatedly, she presses the one she thinks is right and makes a question sound." That sounds like a classic case of guiding an experiment to get the results you want.
(, Thu 18 Feb 2021, 17:31, Reply)