> I ask because every serious study on using modern generative AI tools
There are a lot of studies, and I can't say I've read all of them, but the ones I have read, there hasn't been much focus on how the participants used the LLM to learn. My guess is that it has a lot of effect on the end results. Someone just asking for the answer and then thinking "Lets remember this" will have very different results than someone who does the Socratic method of learning together with a LLM, as just one example.
You know, that's a good point too. The studies I've read all focused on cognition after using an LLM to complete tasks for work or hobbies. I do wonder if there might be a different outcome with learning specifically.