Your response prompts for me a point I left out above: there’s major ambiguity here about “learning.” Learning isn’t one thing. Memorizing definitions of vocabulary words isn’t the same thing as explaining how you might apply a word in different contexts (think categorization or classification). This is one of the major things I spend lots of time on as a history teacher. Ok, great, awesome, we can kinda say what a revolution is. Uh. Uh oh. Why do we have revolutions that are French and Scientific? Those don’t sound super similar. Hey, wait, let me tell y’all about how I got on the internet when I was your age. I had to plug my computer into a wall, dial something, and a box inside my computer would screech at me. Y’all carry the internet around in your hands everywhere you go. Is that a revolution? Etc. That kind of learning is very different than looking a word up in a dictionary. And there are other kinds (procedural learning, which turns out to be actually rather different from other kinds).

Spaced repetition happens everyday outside of a "sit at a desk and learn" setup and is plenty efficient without effort and pain. The obvious one is seeing again and again a concept so much you end up remembering it, like the Dunning Kreuger effect (or to take it darker, being able to recipe an ad you've seen hundreds of time)

If anything, I'd argue the pain and effort can be negative it will still work.

> Spaced repetition takes effort, and causes pain. It is tedious. So it still fits in with the idea proposed

This is not true. Anki is tedious and causes pain. Flashcards are such in general.

But dpaced repetition does not requires either.

I find SRS to be more a scheduling mechanism, not a memory one. If my memory of something is "bad" before SRS, it's going to be bad after, it's just I can let the algorithm refresh it more often than the thing I CAN remember.

Actual memory "devices" (tricks, schemes, etc.) are orthogonal; SRS (for me) just optimizes my time so I don't have to go over shit I know more often than I need to.

For anyone curious, my 2 go-to books on actually learning how to remember are the ones by Higbee (dry, but thorough) and Lorayne (approachable, but feels less academic). I used SRS to remember those 2 authors w/o having to look them up, FWIW. ;-)