Spaced Repetition

Spaced repetition is based on the "forgetting curve" - Hermann Ebbinghaus's finding that we forget information predictably over time, but each time we review information before it's forgotten, we reset the forgetting curve and the next forgetting happens more slowly. Rather than cramming (massed practice) where you review material repeatedly in short time, spaced repetition spaces reviews out over days, weeks, and months. For instance, you might review a vocabulary word the day you learn it, then three days later, then a week later, then two weeks later. With optimal spacing, information moves into long-term memory with relatively little total review time. Research shows spaced repetition is dramatically more effective than cramming - students retain more information with less total study time. Digital flashcard systems like Anki use algorithms to optimize spacing based on how well you know each item - you see items you know less frequently, and items you know infrequently. Spaced repetition works across domains - vocabulary, historical facts, mathematical procedures, any information you want to remember long-term. The key is that review happens before forgetting, preventing the forgetting curve from steepening again.