What is Spaced Repetition? A Guide.

What is spaced repetition? How to use the system for effective learning.

Image What is Spaced Repetition? A Guide

Kids learn by playing. Long study sessions are common with college students. As adults, we need to update our knowledge permanently. Learning is part of our lives, but humans seem to struggle to remember and retain information effectively. Spaced repetition is a method to ingrain new information more reliably and is used in many eLearning products.

Our brain is a powerful machine but there’s a limit to what a human can remember. Practicing spaced repetition can help you learn more efficiently. In this tutorial, we discuss the spaced repetition technique and how you can utilize it for effective learning.

Spaced Repetition – Overview 

Spaced repetition may sound new, but the concept is not exactly new. We all were told the story of the fast Rabbit and the turtle as children and taught that slow and steady wins the race. As long as one is steadfast, one doesn’t have to be fast.

Herman Ebbinghaus – a German psychologist – first introduced the idea of the spaced repetition technique. He’s known for his work in the field of learning and forgetting curves.

Spaced repetition, also known as distributed practice, is a learning technique that involves repeating information at certain intervals. Our brain is programmed to forget information that is not repeated, but it’s possible to slow down the process of forgetting by revisiting or reviewing the information frequently. Sounds familiar, right?

The spaced repetition technique uses repetition to keep information fresh in a person’s short-term memory until it becomes part of the long-term memory. Due to its effectiveness, spaced repetition is considered a great tool for students, especially younger ones. It’s also used to improve long-term memory and individuals with memory disorders.

How Does Spaced Repetition Work?

The human brain is a muscle just like any other in the body. When we utilize it for longer periods, it gets tired and requires a time-out. Stretching too far or putting too much pressure on the muscle can have negative consequences.

Suppose, you wanted to have bigger and stronger biceps and decided to start working out. If you have never lifted weights before, you won’t start with a hundred pounds. Instead, professionals usually recommend people to start small, like five pounds.

Starting with five pounds will give your body time to relax after which you proceed to seven pounds, and so on. By working your way up with the weights in each session, you will be able to handle more weight. You can apply that principle to any other sports too.

Our brain works similarly. However, instead of heavier weights, information is repeated over extended periods to remember. The repetition goes on until the old information is stored in the long-term memory. Learning software takes advantage of that.

Examples – Educational products that use spaced repetition as a learning technique include typing software, speed reading courses, or language courses.

Herman Ebbinghaus’s Forgetting Curve

Image Spaced Repetition - Ebbinghaus - Forgetting Curve Chart

As mentioned earlier, Herman Ebbinghaus focused on the forgetting curve. It’s a memory model that shows how retention declines over time unless we take preventive measures. The fastest drop occurs after 20 minutes and the curve almost levels in one day1.

Herman Ebbinghaus was the first psychologist to systematically tackle memory analysis. He spent several years memorizing made-up syllables and recording the results. The results included data on how many times he studied each list, the time interval between each study session, and the amount of information he remembered.

Thus, he was able to chart the rate of memory decay over time in the forgetting curve. In the next section, let’s look at the spacing effect that will help you better understand how you can work with your brain and not against it.

How the Spacing Effect Works 

Image Spaced Repetition - Spacing Effect

When it comes to reality, things are more complicated than they seem on paper. For instance, how do you remember the name of an old school friend you haven’t seen or met in ages? Street numbers, random conversations, why does our brain bother to store such mundane information?

How does our brain store memories?
In our brain, memories and information are stored in various locations, not just in a single place. That is why we don’t forget the entire concept or experience but forget small details.

Often, a musical note brings up a long-forgotten memory or the smell of fresh cake takes you right back to your childhood! This suggests that even though we think we forgot something, we haven’t.

Herman Ebbinghaus also discovered that our brain stores a small piece of information in our subconscious mind even though it may seem forgotten. He referred to those pieces of information as savings. While savings cannot be consciously brought back to your mind, they do speed up the process of relearning.

Forgetting and remembering are linked together.
When you are on the verge of forgetting something, your brain reinforces the memory while adding new details. That’s why teaching others, quizzes, and practice papers help. Because they highlight what has been almost forgotten.

Memories don’t stay the same.
In our brain, not only new information is stored every day, but it also changes the way we think and see things. It’s rightly said that no person ever reads the same book.

Retrieving memories is better than revisiting memories.
Since we talk so much about repetition, one may think that it’s the best way to learn. On the contrary, the best way to remember is by recalling the information.

Trying to remember something puts strain on one’s brain and makes it easier to remember information in the future. This is why practice tests are a better way to learn than re-reading highlights from your textbook.

Our brain prioritizes recurring information.
When we encounter some information daily, it becomes easier to recall it without even trying. That’s why we never forget mundane information such as an important PIN code (never say never), directions to work, and our signatures.

Implementing the Spaced Repetition System 

Image Spaced Repetition - Spacing Effect

Over time, spaced repetition, like everything else, has evolved. There are two popular ways to implement spaced repetition for effective learning: manually and via apps.

1. Manual Spaced Repetition Technique

Starting with the old-school way of using the spaced repetition technique. Our day-to-day lives are full of things we can’t control, but when life gives you a lemon, make lemonade. Suppose you’re standing in a long queue and know that it will be a while before your turn.

You will naturally be annoyed, take out your phone, and start browsing. However, there’s a more efficient way of utilizing this time – learn something new using spaced repetition.

Manual spaced repetition may involve reading and learning from a notebook or using flashcards. The simplest way to implement flashcard studying is via the Leitner system. It’s a method proposed by a German science journalist, Sebastian Leitner, that involves reviewing various flashcards in increasing intervals.

Here’s how the Leitner system works:

  1. Start by creating flashcards. 
  2. Label three to five boxes with study time intervals. 
  3. The boxes should be labeled as follows:
Box Number Time Interval 
Box 1Every day 
Box 2Every two days
Box 3Once a week 
Box 4Once, every two weeks 
Box 5Retired (to be repeated sometime in the future)

In the Leitner system, every flashcard starts at box 1 and moves to box 2 when you answer a flashcard correctly. If you don’t, it goes right back to box 1 for a fresh start. The same methods are followed for each flashcard in box 2, and so on.

After some time, you will start to see a pattern where some cards are more difficult and require frequent repetition and other cards easily go from one box to the other.

The method of moving between boxes occurs for every card in box 1. It graduates to the next box if you answer it correctly, and stays in the same box if it’s answered incorrectly. Depending on your specific study schedule and the interval boxes, you will end up studying just one or even multiple topics each day.

2. Spaced Repetition via Apps 

Smartphones and apps have changed the way we used to learn things. Now, people find an app to learn something instead of heading to the library. There’s an app for everything and that includes spaced repetition, e.g. speed reading apps or vocabulary apps.

In the following table, we will list additional Windows, OS X, Linux, iPhone, and Android apps for spaced repetition learning.

App Pricing Availability 
SpreederVIP Version (view)Web, Mobile, Browser
Vocab1Pro version (view)Web, Mobile, Browser
Anki Free (except iOS)Android, iOS, Linux, Mac, Windows, Web
BrainscapeFree + Pro version Android, iOS, Web
QuizletFree + Pro version Android, iOS, Web
Cram Free + Pro version Android, iOS, Web
IDoRecallFree + Pro version Web 

Apps offer an advantage over traditional learning, as it may be difficult to take a book or flashcards along, but we take our mobile phones everywhere. Although, remember that spaced learning is about technique, not apps. You need to create flashcards that are effective and make sure that you don’t go over your schedule.

Spaced Repetition – 3 Steps

Image Spaced Repetition System - 3 Learning Steps

As we discussed earlier, spaced repetition learning is all about technique. If the app seems too complicated or you’re unable to follow the exact schedule, here are a few simple ways to make the most out of spaced repetition without a strict schedule.

Step 1: Review the Information 

Spaced repetition stands based on reviewing information over and over. To retain information longer, review it within 24 hours of the initial intake. To make the process easier, make short notes or flashcards with the important points to review the subject on the go.

One thing to keep in mind is that there should be a difference between rereading and recalling. Rereading is simply going through the information again and reviewing involves reading and recalling information from memory. While reviewing, read the important points, close the book and recall the information you just read.

Step 2: Recall Information and Quiz Yourself

The best way to recall information is by letting someone quiz you or take a quick practice exam to put yourself on a test. After day one of learning using the spaced repetition technique, try recalling the information without looking at the notes first. You don’t have to remember everything word-to-word but completely understand the concept.

Repeat the same process every few days to keep your progress in check. This way, you won’t have to have a long study session, but rather, a quick recall session of a few minutes.

Step 3: Revisit the Information Later

At one point, you get a good grip on the information you’ve been trying to memorize. At that point, the topic goes into the retired box. It means that you can give it a rest, but take out the study materials every few days, and study them to make sure that it’s fresh in your memory. This step also lets your brain process the information all over again.

Spaced Repetition – Summary and Conclusion 

Image Spaced Repetition - Space Out Your Learning

Wrapping up our guide about ‘What is spaced repetition?‘. In schools, we’re used to studying with determination, also known as the cramming technique. For years, learning has been seen as something where determination is considered everything.

However, we all know how difficult it is to absorb a large amount of information in one sitting. What’s even more common is forgetting everything as soon as the test begins.

Spaced repetition is indeed the more natural way that accommodates nearly everyone from busy students to professionals. Though it may sound slow and overwhelming at first, as soon as you settle, learning on the go will seem like the best decision you can make. After all, it’s always better to put quality over quantity.

If you like this tutorial about spaced repetition, please help spread the word and share it with family, friends, and work colleagues. Have you got more tips on how to best use spaced repetition in learning? Feel free to discuss them in the comments below.

Sources: Herman Ebbinghaus – 1 | Forgetting curve – 2 | Spacing Effect – 3
Credits: Creative Commons Attribution – Leitner System – 4