This is a very interesting subject. Michael Manring had some ideas on it in this interview:
Michael Manring On How We Learn - YouTube
Basically, a lot of learning something happens when you are away from your intrument. That's why, in my experience, practicing something often for smaller periods of time seems to yield better results.
Michael Manring On How We Learn - YouTube
Basically, a lot of learning something happens when you are away from your intrument. That's why, in my experience, practicing something often for smaller periods of time seems to yield better results.