The guitarist of AC/DC on their last world tour had to relearn the songs before each show as he was suffering from the early stages of dementia (article)
CRT's have a long afterglow so has plasmas, so there is defenetly no flicker as the cause of dogs not being "able" to see TV.
LCD's on the other hand was much hated at first because they could'nt refresh fast enough and that made them flicker.
Back then pc graphics cards didnt have refresh rates past 70Hz because there was no "need" for it as the CRT's could'nt keep up.
100 years ago some films was done in 16 pictures/second, does that mean that we cant see then because we would "only" see flicker?