Well, first of all “deliberate practice” is different from “learning”. The paper is concerned with ability to perform which is the goal of the deliberate practice, not with understanding which is the goal of learning.
Second, the paper is unwilling to commit to this number saying (emphasis mine) ”...raising the possibility of a more general limit on the maximal amount of deliberate practice that can be sustained over extended time without exhaustion.”
I certainly accept the idea that resources such as concentration, attention, etc. are limited (though they recover over time) and you can’t just be at your best all your waking time. But there doesn’t seem to be enough evidence to fix hard numbers (like 2-4 hours) for that. And, of course, I expect there to be fair amount of individual variation, as well as some dependency on what exactly is it that you’re learning or practicing.
Do you have a link?
See pg. 391-392 of The Role of Deliberate Practice in the Acquisition of Expert Performance.pdf), the paper that kicked off the field. A better summary is that 2-4 hours is the maximum sustainable amount of deliberate practice in a day.
Ah, so that’s where you are coming from.
Well, first of all “deliberate practice” is different from “learning”. The paper is concerned with ability to perform which is the goal of the deliberate practice, not with understanding which is the goal of learning.
Second, the paper is unwilling to commit to this number saying (emphasis mine) ”...raising the possibility of a more general limit on the maximal amount of deliberate practice that can be sustained over extended time without exhaustion.”
I certainly accept the idea that resources such as concentration, attention, etc. are limited (though they recover over time) and you can’t just be at your best all your waking time. But there doesn’t seem to be enough evidence to fix hard numbers (like 2-4 hours) for that. And, of course, I expect there to be fair amount of individual variation, as well as some dependency on what exactly is it that you’re learning or practicing.