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How Spaced Repetition Helps You Remember Everything

March 2026 - 8 min read

You have probably experienced this: you spend an evening cramming for a test, feel confident the next morning, and then forget most of it within a week. This is not a failure of your memory - it is a predictable consequence of how human memory works. Spaced repetition is a study technique that works with your brain's natural forgetting patterns instead of against them, and decades of research show it is one of the most effective ways to build lasting knowledge.

The Forgetting Curve

In 1885, German psychologist Hermann Ebbinghaus discovered that memory decays exponentially over time. After learning something new, you forget approximately 50% within an hour, 70% within a day, and 90% within a week - unless you actively review it. He called this pattern the "forgetting curve."

The critical insight is that each time you successfully recall something, the forgetting curve flattens. The first review might keep the information in memory for two days. The second review extends it to a week. The third to a month. Eventually, the intervals between reviews stretch to months or even years, and the information becomes effectively permanent.

What Is Spaced Repetition?

Spaced repetition is a study system that schedules reviews at increasing intervals based on how well you know each piece of information. Instead of reviewing everything equally, it focuses your time on what you are about to forget while leaving well-known material for later review.

The basic principle is simple: if you remember something easily, wait longer before reviewing it. If you struggle to recall it, review it again soon. This means you spend most of your study time on the material that needs the most attention, making every minute of revision more efficient.

The SM-2 Algorithm

The most widely used spaced repetition algorithm is SM-2, developed by Piotr Wozniak in 1987. It works by assigning each piece of information an "easiness factor" that adjusts based on your performance. When you review a flashcard, you rate how easy it was to recall (typically on a scale of 0-5). The algorithm then calculates when you should next see that card:

If you rate a card as difficult, the easiness factor decreases and the interval shortens. If you rate it as easy, the factor increases and intervals grow longer. Over time, easy cards appear less often while difficult ones keep coming back until you master them.

Why Cramming Does Not Work

Cramming feels effective because of a psychological illusion called "fluency." When you read your notes repeatedly in a short period, the information feels familiar and accessible. You recognise the words, the diagrams look right, and you feel confident. But recognition is not the same as recall.

The test does not ask "does this look familiar?" It asks you to produce the answer from memory. Cramming builds recognition without building the neural pathways needed for recall. Spaced repetition, by contrast, forces you to actively retrieve information from memory each time - strengthening those pathways with every successful recall.

Key insight: The effort of trying to remember something is what makes the memory stronger. If recall feels too easy, the review is not doing much. A slight struggle to remember is actually a sign that the review is happening at the right time.

How to Use Spaced Repetition for IB MYP

1. Identify What to Memorise

Not everything needs spaced repetition. It works best for discrete facts and definitions that you need to recall quickly: formulae, vocabulary, key dates, element properties, literary device definitions, and similar factual knowledge. For understanding concepts and solving problems, active practice (like working through questions) is more appropriate.

2. Create Effective Flashcards

Good flashcards follow the "minimum information principle" - each card should test exactly one piece of knowledge. Instead of putting an entire topic on one card, break it into atomic facts:

Keep the question specific and the answer concise. If a card consistently takes you more than 10 seconds to answer, consider splitting it into smaller cards.

3. Review Consistently

Spaced repetition only works if you review regularly. Set aside 10-15 minutes daily for your review queue. The system will automatically prioritise the cards you most need to see. Skipping days causes cards to pile up, which makes the next session feel overwhelming and defeats the purpose of spacing.

4. Be Honest With Your Ratings

When the system asks how well you remembered something, be honest. Marking a difficult card as "easy" means it will not come back soon enough, and you will forget it. Marking an easy card as "hard" wastes time on material you already know. The algorithm only works well when it receives accurate feedback about your actual knowledge.

5. Combine With Active Practice

Spaced repetition handles the memorisation layer - formulae, definitions, facts. But IB MYP assessments also test understanding, application, and analysis. Combine your flashcard reviews with active problem-solving practice. Use the flashcards to ensure you know the foundational facts, then apply that knowledge by working through questions and past papers.

Spaced Repetition Across Subjects

Try spaced repetition on Project 56

Our chemistry flashcards use the SM-2 algorithm to schedule reviews automatically. 121 cards covering all 8 topics.

Try Chemistry Flashcards

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