What is Spaced Repetition?

You read a book. A week later, you can barely remember the key ideas. Sound familiar?

This isn't a personal failing—it's how human memory works. The good news? There's a scientifically-proven technique to change this: spaced repetition.

The Science of Forgetting

In 1885, German psychologist Hermann Ebbinghaus conducted a groundbreaking experiment. He memorized lists of nonsense syllables and tested himself at various intervals. What he discovered became known as the forgetting curve.

Here's the uncomfortable truth: without any review, we forget approximately:

• 50% within an hour
• 70% within 24 hours
• 90% within a month

That book you read last month? Most of it is gone. But Ebbinghaus also discovered something hopeful: strategic review can dramatically slow this decay.

What is Spaced Repetition?

Spaced repetition is a learning technique where you review information at increasing intervals. The idea is simple: review something right before you forget it.

When you successfully recall something, the memory becomes stronger, and you can wait longer before the next review. When you struggle or forget, you review sooner. Over time, information moves from short-term to long-term memory.

A typical spacing schedule might look like:

• First review: 1 day after learning
• Second review: 3 days later
• Third review: 7 days later
• Fourth review: 14 days later
• Fifth review: 30 days later

After just 5 reviews over a month, information that would have been 90% forgotten is now firmly in long-term memory.

Why It Works

Spaced repetition exploits two key principles of memory science:

1. The Testing Effect

Actively recalling information strengthens memory far more than passive review. When you quiz yourself, you're not just checking if you know something—you're actually making the memory stronger.

2. Desirable Difficulty

Memories formed under slightly difficult conditions are more durable. By waiting until you're about to forget (but haven't yet), you create the optimal level of difficulty for learning.

Spaced Repetition vs. Cramming

Cramming can work for short-term recall (passing a test tomorrow), but it's terrible for long-term retention. Here's why spaced repetition wins:

• Less total time: 5 short sessions beats 1 marathon session
• Longer retention: Information stays accessible for months or years
• Better understanding: Spacing allows for deeper processing
• Lower stress: No last-minute panic sessions

How to Use Spaced Repetition

The traditional approach uses flashcards with algorithms like SM-2 (used by Anki) or Leitner boxes. But there's a simpler way:

The LearnLog Approach

1. Log one insight daily: When you learn something worth remembering, write it down in your own words
2. Let AI quiz you: LearnLog generates questions that test your understanding, not just recognition
3. Trust the schedule: The app handles the spacing—you just show up when it's time to review

This approach removes the friction of traditional spaced repetition systems while keeping the benefits.

The Research

Spaced repetition isn't just theory. It's backed by over a century of research:

• Cepeda et al. (2006) found that spaced practice leads to 10-30% better retention than massed practice
• Karpicke & Roediger (2008) showed that testing is more effective than re-studying, even when you get the wrong answer
• Dunlosky et al. (2013) ranked practice testing and distributed practice as the two most effective learning techniques

Start Today

You don't need to overhaul your learning habits. Start with one insight per day. Review when prompted. In a month, you'll have retained more than most people retain in a year.

The forgetting curve is working against you right now. Spaced repetition puts it to work for you instead.