I often see discussion here of Anki or other Spaced Repetition Systems for learning.  To me, these are great for "higher levels" of knowledge -- things more closely associated with System 2 than System 1.

Are there similar advantages to be had (and systems that exist for) "lower levels" of knowledge?  I think this would apply to things that are implicit learning, intuitions, as well as System-1 level knowledge.

I want to distinguish this from "regular practice", which I don't think has spaced repetition qualities.

• For example, meditation (to me) includes regular practice in equanimity -- I (so far) don't know of an effect where I can exponentially spread out my meditation practice to make it "last longer"
• Running is another example, where regular practice makes me better, but I don't feel like I would get much out of exponentially spacing it (I think it could be argued that skill at running is only a small part "knowing" and largely other things like musculature, which would make this a bad example)

I would greatly value contributions of:

• Studies looking at spaced repetition for intuitions/implicit learning/etc
• Reasons why these might be possible or exist
• Reasons why these might be impossible
• Proposals to how to design experiments to test this