Don’t worry about the details; it was just a made-up story in the book Art & Fear; I have never seen any evidence such a pottery class ever existed. https://kk.org/cooltools/art-fear/
> The ceramics teacher announced on opening day that he was dividing the class into two groups. All those on the left side of the studio, he said, would be graded solely on the quantity of work they produced, all those on the right solely on its quality. His procedure was simple: on the final day of class he would bring in his bathroom scales and weigh the work of the "quantity" group: fifty pound of pots rated an "A", forty pounds a "B", and so on. Those being graded on "quality", however, needed to produce only one pot -albeit a perfect one - to get an "A". Well, came grading time and a curious fact emerged: the works of highest quality were all produced by the group being graded for quantity. It seems that while the "quantity" group was busily churning out piles of work - and learning from their mistakes - the "quality" group had sat theorizing about perfection, and in the end had little more to show for their efforts than grandiose theories and a pile of dead clay.
James Clear reached out to the authors of Art& Fear and this is his footnote: (Link:https://jamesclear.com/repetitions)
This story comes from page 29 of Art & Fear by David Bayles and Ted Orland. In an email conversation with Orland on October 18, 2016, he explained the origins of the story. “Yes, the ‘ceramics story’ in ‘Art & Fear’ is indeed true, allowing for some literary license in the retelling. Its real-world origin was as a gambit employed by photographer Jerry Uelsmann to motivate his Beginning Photography students at the University of Florida. As retold in ‘Art & Fear’ it faithfully captures the scene as Jerry told it to me—except I replaced photography with ceramics as the medium being explored. Admittedly, it would’ve been easier to retain photography as the art medium being discussed, but David Bayles (co-author) & I are both photographers ourselves, and at the time we were consciously trying to broaden the range of media being referenced in the text. The intriguing thing to me is that it hardly matters what art form was invoked—the moral of the story appears to hold equally true straight across the whole art spectrum (and even outside the arts, for that matter).” Later in that same email, Orland said, “You have our permission to reprint the any or all of the ‘ceramics’ passage in your forthcoming book.” In the end, I settled on publishing an adapted version, which combines their telling of the ceramics story with facts from the original source of Uelsmann’s photography students. David Bayles and Ted Orland, Art & Fear: Observations on the Perils (and Rewards) of Artmaking (Santa Cruz, CA: Image Continuum Press, 1993), 29.
I've found that using digital to gather new skills is terrific, but yet I find some of the work I am most satisfied with is analog; I believe it is mostly down to my own lack of self discipline - when shooting digital, exposures are free and hence I shoot lots and lots.
When out with my Texas Leica (A Fuji G690BL, a 6*9 rangefinder), getting eight exposures to the roll, I take those extra couple of moments to ensure I get it all right.
Part of what stuck out to me, though, was that the anecdote aligned with my personal experiences of things that were once difficult until I ended up having to do them everyday for one reason or another.
But you're right, that's still a far way off from there being some actual study or otherwise repeatable exercise to show this in a clinical setting for learning new skills.
And anyway the pottery principle is not really sound either - I can suppose that the group tasked with producing a pot a day produces a better pot at the end than the group that was given a long time, but let us assume pot-makers both extremely skilled - one is tasked with making a pot a day for 30 days, the other making a pot in 30 days - which pot under those conditions will be better? The pottery principle is only interesting in explaining how to build a skill, but does not have anything to say about what to expect from those who have already mastered a skill.
You can make the same very bad $creative_product every day indefinitely without improving at all.
Which is why there has to be at least some assessment and feedback. That's the big benefit of having a teacher, mentor, and/or the feedback of peers, customers, or an audience.
If you have a mediocre talent they'll steer you towards making the most of it. If you have exceptional talent their feedback may be wrong or misleading, but it should at least make you think more deeply about your relationship with what you're doing.
You can't assess your own work realistically unless you have something to compare it with, and the critical skills to understand which features matter.
There have of course been studies on goal setting and achievement (one of which is mentioned in the above pdf) but while they show an effect, they don't show the spectacular results of the made up study.