While retrieval practice is the single most powerful tactic for building robust recallability of the concepts and facts that you want to remember, distributing the practices of each item, over time, popularly know as spaced-repetition, makes this tactic enormously more effective.

There is a massive body of research literature to support this observation and the best compilation of the research has been created by Gwern Branwen.

Spaced repetition was at the core of how I transformed myself from a lifelong mediocre student and graduated #1 in my medical school class. You can achieve similar success with your studies.

To understand why spaced retrieval practice is so effective, you have to first understand our propensity to forget what we learn. This innate feature of human memory was researched and then described by Hermann Ebbinghaus in the 1880s. He practiced memorizing nonsense syllables and then tested his recall over time. He discovered an exponential decay of recallability of the syllables in the hours, days and weeks following memorizing them.

We rapidly forget what we learn, with the loss especially most severe in the initial hours.

Spaced-repetition of retrieval practice tames the forgetting curve.

Retrievability of Information (ROI) is secured by retrieval practice. No other tactic compares with spaced-repetition.

https://youtu.be/eVajQPuRmk8

https://youtu.be/Z-zNHHpXoMM

https://youtu.be/2h6tEEbpwJo

https://youtu.be/h5PLO4XAXhs

https://youtu.be/DNadmXWEYFw