Problem is: what is "evidence"? This method is used in Chinese circus with good success for acrobats to learn virtuoso acrobat movements very quickly. Do you consider that evidence? A Chinese trainer of acrobat children showed this principle to Alberto Guerrero, Glen Gould's teacher, who simply implemented it without thinking. Chinese and Japanese trainers rarely explain why you have to train something in a certain way in martial arts, for a sample. They just say: do this or that because they are masters and know from long experience that it works. If you start asking questions, they will kindly smile, turn around or send you away and tell you never to come back. Knowing why is not important for good results, especially for students. He/she is humble and does what is told. P.S.: Besides, the training principle may be correct but the (pseudo)scientific explanation may be filled with incorrect assumptions. This is the case in most piano "methods". Story of Guerrero finger tapping is here: https://www.musicandhealth.co.uk/articles/tapping.html
Chinese and Japanese trainers rarely explain why you have to train something in a certain way in martial arts, for a sample. They just say: do this or that because they are masters and know from long experience that it works. If you start asking questions, they will kindly smile, turn around or send you away and tell you never to come back. Knowing why is not important for good results, especially for students. He/she is humble and does what is told.
I think martial arts training is a very good example, for two reasons you may not have thought of.First, most traditional teachers use a "one size fits all" approach for every student. Some succeed, some fail, they don't care. They expect to weed out the less successful students.Second, a huge amount of traditional martial arts techniques don't actually work. This never shakes the belief of either student or teacher, unless either is dumb enough to enter an MMA competition and get owned.
Thanks for the link dima. It's not evidence that it works but it's very interesting re: the origin. Surely Gould is the last pianist, although maybe second to Lang Lang, when you think of 'whilst remembering the relaxed and effortless feel'?
Yes Michelangeli is very much the man. I believe there's an Italian school which eschews superfluous movement.