Spaced repetition: a hack to make your brain store information

Using spaced repetition as a study technique is effective because you are deliberately hacking the way your brain works

Unlock your brain power by understanding the fundamental differences between the way your brain and your computer process information.
Unlock your brain power by understanding the fundamental differences between the way your brain and your computer process information. Photograph: mediacolor's/Alamy

Late night dates with a 600-page textbook and a multipack of Red Bull are a familiar encounter for many people. Whether in school, university or work, we all find ourselves in situations where we have to learn a vast quantity of information in a very short period of time.

In these instances, almost all of us resort to the age-old study technique of reading through the textbook over and over again in the hope that some of it will stick.

However, this study technique is not only tedious and repetitive, it’s also ineffective. It is completely misaligned with how our brains actually work, according to basic neuroscience and psychology research.

Fortunately, that same research paves the way for alternative study methods which work with, rather than against, our brain. And of those methods, spaced repetition is one of the most interesting. It can help if you’re trying to learn a new language, remember your entire musculoskeletal anatomy, or preparing for a big exam.

Spaced repetition

A simple way to do spaced repetition is to use flashcards organised into a box. Set up a schedule for when you will revise the cards in each of the sections in your box. If you answer a card correctly, you put it into a section that you will revisit less frequently in the future, whereas if you get the answer wrong, you move the card into a section scheduled for frequent visits.


You could set up this system yourself, though software is now available to handle card organisation automatically and has gained a loyal online following. Why does it work? By taking advantage of the way our brain has evolved.

Understanding the brain

Something as inherently complex and mysterious as the brain is difficult to describe in literal terms. If asked “how does the brain work?”, we’re likely to say something along the lines of “like an organic computer”. It’s not surprising that, living in a digital world, we connect the two so readily.

However, it’s easy to forget that there are also fundamental differences in how brains and computers process and store information.

Computers store whatever information they are told to store. A video camera is designed with the sole purpose of capturing light and sound information within its field of view, when it is told to do so. The brain, however, is something we have very little direct control over. So you have no more direct control over your how much of a textbook you can remember than you do over your blood pressure.

The second major difference between the brain and a computer is in how information is processed. It’s tempting to think our memories are stored as discrete “files” somewhere in the brain, like a camera. We might imagine that when we remember an event in our lives, or a piece of information we studied, we’re “opening” that file.

But science tells us this isn’t true. A “memory” doesn’t exist in any one place in the brain, but is an emergent feature of many different parts of the brain firing in a certain way. When we learn something, it isn’t stored in a single location, but is instantly scattered across many different regions of the brain.

Finally, the brain has limitations that are, at least for now, impossible to overcome. Studies have consistently shown that we can only remember five to seven new pieces of information at a time. It’s fascinating research, but it also has practical implications for how we should learn.

Hacking your brain

Any effective approach to learning has to be developed with the brain’s inherent limitations in mind. If we know that the brain cannot effectively store and recall lots of information in a short period of time, then “cramming” is a recipe for disaster.

Similarly, we know that the brain preferentially stores information it deems to be important. It strengthens and consolidates memories of things it encounters regularly and frequently. So spaced repetition – revisiting information regularly at set intervals over time – makes a lot of sense.

Spaced repetition is simple, but highly effective because it deliberately hacks the way your brain works. It forces learning to be effortful, and like muscles, the brain responds to that stimulus by strengthening the connections between nerve cells. By spacing the intervals out, you’re further exercising these connections each time. It produces long-term, durable retention of knowledge, and in my experience, once people start using it, they swear by it.

Work smart, not hard

The way we think about health has been revolutionised by our growing evidence of how the body works. Yet the way most of us approach learning remains the same as it has for centuries. Spaced repetition is just one of the ways we can become evidence-based learners, allowing us to learn more in less time.

James Gupta (@gupta_james) is a medical student at Leeds University, and the CEO of Synap, an online learning platform influenced by spaced repetition and other learning techniques.

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