The Science of Spaced Repetition
A minimal library of the learning principles behind UltraMemory: spacing, retrieval, adaptive difficulty, evolving prompts, and transfer.
Memory fundamentals
The mechanics underneath durable recall.
Why spacing and difficulty matter, and why scheduling should adapt to the retention horizon.
Review design
How a prompt should behave as memory gets stronger.
From active recall to synthesis, these pages explain the design choices behind how reviews evolve.
Active recall, always
Retrieval is not just assessment. It is the mechanism that changes the memory.
Prompts that evolve
Prompt type shapes what retrieval makes the learner do, so prompts should become more generative over time.
Vary cues, not questions
Memory is cue-dependent. If retrieval only works from one path, it is fragile.
Synthesis prompts
Advanced review is not just recall. It is comparison, discrimination, and transfer.
Feedback and error correction
Feedback is not decoration. It is part of how retrieval becomes corrective rather than misleading.
Outside the session
What learning feels like vs what actually lasts.
Metacognition, fluency illusions, and why usable vocabulary needs more than recognition.