I have often wondered this about people doing the napping versus sleeping experiment. Euphoria makes you feel like you know so much more than you do.
I know of maybe one or two people who gave themselves cognitive tests during their experience. I don't recall the results but I clearly didn't take them seriously since I'm still unconvinced. I don't know about you guys but I tend to do better if I'm given the same kind of test three or four times. So if I were doing this experiment and my results stayed steady, I'd objectively be losing capacity versus the control.
There's studies on "brain training" apps like Lumosity that tend to show that all you're improving at is the specific test, not the underlying mental capacity like working memory.
And a related anecdote: I once asked my psychologist to do an IQ test on me, mainly out of curiosity. She refused, basically giving the logic you did. We have no reason to believe your IQ is low, or even average, and if we did do a test, and at some future point we needed a test for actual diagnostic purposes(say if I had a stroke or something), it could taint the result.
So I'd say you're right on the money wrt the limited usefulness of doing these neuropsych tests repeatedly. Especially over short periods.
I know of maybe one or two people who gave themselves cognitive tests during their experience. I don't recall the results but I clearly didn't take them seriously since I'm still unconvinced. I don't know about you guys but I tend to do better if I'm given the same kind of test three or four times. So if I were doing this experiment and my results stayed steady, I'd objectively be losing capacity versus the control.