Our methodology
Memorize combines two well-documented study techniques: active recall and spaced repetition. This page explains how they work, how we apply them and where the method has limits.
The forgetting curve
In the late 19th century, Hermann Ebbinghaus showed that we forget quickly right after learning, and that the loss slows down over time. The practical conclusion is direct: reviewing when the memory is just starting to fade is more efficient than reviewing too early (wasted effort) or too late (you have to relearn).
Active recall
Trying to retrieve a piece of information strengthens memory more than rereading the material. That is why Memorize is built around questions: every card requires you to produce the answer before checking it. Rereading feels like mastery; actually retrieving is what builds memory.
Spaced repetition and the SM-2 algorithm
We use SM-2, a spaced repetition algorithm published in the 1980s-90s and widely adopted since. After each answer it adjusts the interval until the next review according to how easy it was for you: cards you get right comfortably come back later; cards you miss come back soon. The reviews due today are gathered into a single queue.
The four study modes
Question and answer trains pure retrieval. Multiple choice helps with recognition and early stages. The timed assessment adds time pressure and produces a performance report. Smart repetition only ends the session once you get every card right, bringing back the ones you missed.
Limits of the method
Spaced repetition is effective for memorizing facts, vocabulary, definitions and associations — it does not replace deep understanding, applied practice or problem solving. It also depends on consistency: the schedule only works if the reviews actually happen. And poorly written cards (long, ambiguous or bundling several ideas) hurt the outcome no matter how good the algorithm is.
References
- Ebbinghaus, H. (1885). Über das Gedächtnis. Leipzig: Duncker & Humblot.
- Wozniak, P. A., & Gorzelanczyk, E. J. (1994). Optimization of repetition spacing in the practice of learning. Acta Neurobiologiae Experimentalis, 54(1), 59–62.
- Roediger, H. L., & Karpicke, J. D. (2006). Test-enhanced learning: Taking memory tests improves long-term retention. Psychological Science, 17(3), 249–255.
- Cepeda, N. J., Pashler, H., Vul, E., Wixted, J. T., & Rohrer, D. (2006). Distributed practice in verbal recall tasks: A review and quantitative synthesis. Psychological Bulletin, 132(3), 354–380.