The Ebbinghaus Forgetting Curve & Spaced Repetition Algorithms

Part 1: The Exponential Decay of Memory

Within 24 hours of learning something new, you forget approximately 70% of the details unless you reinforce it. But each time you review, the decay slope flattens, increasing the concept's stability half-life.

Part 2: How Algorithmic Schedulers (SM-2 & FSRS) Work

1. 1. Initial Review: After passing a quiz, the card's interval starts at 1 day.
2. 2. Performance Rating: The learner rates recall difficulty (Forgot, Hard, Good, Easy).
3. 3. Stability Multiplier: Successful recall multiplies the interval by an ease factor (e.g. 1d -> 3d -> 8d -> 21d -> 60d).
4. 4. Lapse Reset: If forgotten, the interval resets, and the item is temporarily requeued for high-frequency reinforcement.

Part 3: RealLearn Cognitive Memory Architecture

Rather than drowning users in an unbounded 800-card Anki backlog, RealLearn's Cognitive Memory extracts canonical concept nodes and delivers focused 2-minute high-yield recall pulses.