A spaced-repetition memory system combines the Testing effect and the Spacing effect to enable efficient memorization of many thousands of facts (Spaced repetition memory systems are extremely efficient). Some people also use them for a broader set of tasks (see below). Spaced repetition memory systems make memory a choice.
The first consumer system of this kind was Supermemo, created by Piotr Wozniak. It adopted and popularized the term “spaced repetition”; prior literature had used a variety of terms (often referring to more specific facets of the underlying phenomenon).
Branwen, G. (2009). Spaced Repetition for Efficient Learning. Retrieved December 16, 2019, from https://www.gwern.net/Spaced-repetition