"Every perception is to some degree an act of creation, and every act of memory is to some degree an act of imagination."
-- Gerald Edelman, Second Nature: Brain Science and Human Knowledge
2 The early impact of the prototype mnemonic medium4 The early impact of the prototype mnemonic mediumThe early impact of the prototype mnemonic mediumHow can we develop transformative tools for thought？2020-10-18Journal
This is the big, counterintuitive advantage of spaced repetition: you get exponential returns for increased effort. On average, every extra minute of effort spent in review provides more and more benefit. This is in sharp contrast with most experiences in life, where we run into diminishing returns. For instance, ordinarily if you increase the amount of time you spend reading by 50%, you expect to get no more than 50% extra out of it, and possibly much less. But with the mnemonic medium when you increase the amount of time you spend reading by 50%, you may get 10x as much out of it. Of course, we don't quite mean those numbers literally. But it does convey the key idea of getting a strongly non-linear return. It's a change in the quality of the medium.