Chapter 2
Spaced Repetition & The Forgetting Curve
The 8 Laws of Learning
  1. Explanation
  2. Demonstration
  3. Imitation
  4. Repetition
  5. Repetition
  6. Repetition
  7. Repetition
  8. Repetition
— John Wooden, legendary basketball coach
Within a day of learning something new, roughly two-thirds of it has already slipped from memory. By the end of the month, almost nothing remains. This is not a failure of effort or intelligence; it is the default behavior of every human brain ever studied.
The Forgetting Curve: 140 Years of Evidence
In 1885, the German psychologist Hermann Ebbinghaus ran one of the first rigorous experiments on human memory. He memorized lists of nonsense syllables, then measured how quickly he forgot them. The result, a steep exponential decline he called the "forgetting curve", has been replicated hundreds of times in the century and a half since.
The numbers are sobering. Without any review, most people lose roughly 70% of newly learned material within 24 hours and around 80% within a month. The curve is relentless, and it applies to everyone: medical students, language learners, professional developers, anyone who needs to retain information over time.
~70%
forgotten within 24 hours
~80%
forgotten within 30 days
140+
years of replicated research
Interactive
The Forgetting Curve
Without review, memory decays steeply. Toggle to see how spaced reviews change the curve.
0%25%50%75%100%Now5d10d15d20d25d30dTime
Memory retention without any review
But Ebbinghaus also discovered the antidote. Each time you successfully retrieve a piece of information just before it would have faded, the memory trace strengthens and the next forgetting curve becomes shallower. Strategically timed reviews can turn a fragile, hours-old memory into one that persists for months or years.
Why Cramming Fails
Wooden understood that repetition is the backbone of learning. But the way those repetitions are distributed matters enormously. Cramming fifty repetitions into a single late-night session might get you through tomorrow's quiz, but almost none of that knowledge will survive the following week.
The alternative, spreading the same number of repetitions across several days or weeks, produces dramatically better retention. Cognitive scientists call this distributed practice, and it is one of the most dependable findings in all of experimental psychology. When you space reviews out, each session forces your brain to reconstruct the memory from partial traces, and that reconstruction effort is what builds durable long-term storage.
“Distributed practice produces substantially greater retention than massed practice. This spacing effect is one of the most replicable findings in experimental psychology.”
— Cepeda et al. (2006)
Interleaving: Why Mixing Topics Beats Blocking
There is a natural temptation to finish all the problems on one topic before moving to the next. It feels orderly and productive. But research consistently shows that interleaving, alternating between different topics or problem types within a single study session, leads to stronger, more flexible learning.
The reason is subtle. When you practice one topic in isolation, you always know which strategy to apply. When topics are mixed together, you have to first identify what kind of problem you are looking at before you can solve it. That extra step of discrimination is closer to how exams and real-world situations actually work, and it forces deeper processing.
The Exam Scheduler
RemNote automates spaced repetition scheduling so you can focus on learning rather than logistics. Each day, it surfaces the flashcards you are closest to forgetting. After each review, the FSRS algorithm, the most advanced spacing algorithm currently available, adjusts the next review date based on how well you recalled the material.
RemNote's Exam Scheduler takes this a step further. Tell it the date of your exam and which material you need to cover, and it builds a day-by-day review plan that ensures every card is seen enough times before test day. Instead of guessing how to divide your time, the scheduler allocates reviews so that the hardest material gets more attention and the easier cards stay fresh with minimal effort.
Because the scheduler is powered by the same FSRS algorithm, it can predict which cards are most at risk of being forgotten by exam day and front-load those reviews. The result is a study plan that adapts to your actual memory, not a generic timetable that treats every topic the same.
Further Reading
  • Ebbinghaus, H. (1885). Memory: A Contribution to Experimental Psychology.
  • Cepeda, N. J., et al. (2006). “Distributed practice in verbal recall tasks.” Psychological Bulletin.
  • Kang, S. H. K. (2016). “Spaced repetition promotes efficient and effective learning.” Policy Insights from the Behavioral and Brain Sciences.
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