Dux AI — Spaced Repetition Study Routine | dux-ai.com
A table of dated milestones: Ebbinghaus in the 1880s with the forgetting curve, the Leitner box system of the 1970s, and the SM family of algorithms from SM-0 to SM-18.
The method of spaced repetition was first conceived of in the 1880s by the German scientist Hermann Ebbinghaus. He created the forgetting curve, a graph portraying the loss of learned information over time, and postulated that it can be curbed by reviewing material at increasing intervals.
The Leitner system of the 1970s turned the postulate into a working routine. Flashcards are sorted into groups reviewed at increasing intervals; correctly answered cards advance to the next box, incorrectly answered cards return to the first box.
On narrow screens, swipe or scroll the plate sideways.
The SM family of algorithms ranges from SM-0, a paper-and-pencil prototype, to SM-18, which is built into SuperMemo 18 and 19. Each step in the family refines the interval schedule, while the card flow — advance on a right answer, return on a wrong one — stays the same as in the Leitner layout.
Reading the milestones tells you which version of the method you are running. A paper box layout is the Leitner system; an algorithm that computes intervals for you is an SM-family implementation, up to SM-18 in SuperMemo 18 and 19.
All three milestones share one postulate: review material at increasing intervals. Ebbinghaus stated it, the Leitner system implements it with boxes, and the SM family implements it with algorithms from SM-0 to SM-18.
Further reading