Memorization. One of the most critical functions of our brain when it comes to studying. Most of us have experienced the internal pain of forgetting something important when the test is handed to us, but many of us don’t really know how to prevent it.
What if we could optimize how much we remembered? Keeping study time at a minimum and the memorization of any concept more feasible.
As life gets busier, we only have so much time to use up on studying for next week’s exam, so bringing in new tools like this could be a lifesaver when retention is the only thing between you passing or failing your exam. Not only that, but this method of studying has over 80 years of scientific research and evidence to stand behind it.
Today we are going to dive deeper into what spaced repetition actually is and the science that bolsters its viability.
What is Spaced Repetition?
Spaced repetition is one of the most effective ways to increase long-term memorization. It’s all about making the game of memorization easier. This method also makes the decision between studying and sleeping much easier when it comes to testing day.
Cramming loads of information into your brain the day before the test is probably one of the worst things you can do to recall important information when you need it most, and a lot of students tend to do this.
The catch with memorization is that you can easily store new information in your brain, but the struggle is retrieving it. So instead you can space out short studying repetitions between long time intervals.
You start off with small intervals between study repetitions, then exponentially increase the interval lengths each time you study. Here’s an example:
- First study repetition: after 1 day
- Second study repetition: after 7 days
- Third study repetition: after 16 days
- Fourth study repetition: after 35 days
- and so on…
These time intervals allow your brain some time to actually process the information from before and then recall the information from a further time back on each repetition. Overall, making it more and more difficult to recall the information (which is actually increasing your retention span).
So not only are you learning difficult concepts more efficiently, but you’re saving your precious time along with it with short studying sessions.
But then arises another problem. Not every test date is the same. Not every schedule is made equal. So what if you needed to drill a concept into your mind by next week (or even sooner)?
I’m glad you asked. Here’s a table showing you some examples of how you can optimize your first and second study repetitions:
| Time to Test | First Study Gap |
| 1 Week | 1-2 Days |
| 1 Month | 1 Week |
| 3 Months | 2 Weeks |
| 6 Months | 3 Weeks |
| 1 Year | 1 Month |
So to answer your question: if you had to memorize a concept by next week then you would simply start learning the concept today, then study it again by tomorrow or the day after, and then you would keep going.
It’s important to keep in mind that these numbers are very generalized. No set of numbers is going to be specific for every student’s schedule. This is merely just a guideline for you to stretch based on your own time available.
The Science Around Spaced Repetition
You’re probably wondering “Does spaced repetition actually work or is it just hyped beyond compare?” To give you the short answer, yes, it works very well. This simple answer is backed by years and years of research and study from scientists across the globe.
From 1880 to 1885, German psychologist Hermann Ebbinghaus ran a limited, incomplete study on himself and published his hypothesis in 1885. It was called “Memory: A Contribution to Experimental Psychology.”
Ebbinghaus studied the retention of random syllables such as “WID” or “ZOF” and would repeatedly test himself after various time periods to record the results.
He plotted these results on a graph creating what is now known as the “forgetting curve“. This is the evidence behind why spaced repetition is so useful. Again, your brain can hold all the information in the world, but forgetting it is why we use spaced repetitions in the first place.
A scientist named Herbert J would continue Ebbinghaus’s work in 1939. Spitzer investigated what effects the spacing of material and tests had on recall and retention. His results were very intriguing, but it would take a few decades for anyone to touch on this topic again.
Fast forward to 1989, another scientist named Frank N. Dempster published a review of the scholarly literature in the Educational Psychology Review. After reviewing more than 100 studies, he would later publish a small statement article that would officially start the overwhelming research on spaced repetition.
In this article, he came to the conclusion that “spaced repetitions—regardless of whether they are in the form of additional study opportunities or successful tests—are a highly effective means of promoting learning.” This was only the beginning.
In 1991, a team of researchers at Villanova University ran a two-part, spaced learning experiment. In part 1 they studied how spaced repetitions would affect young kids (first, second, and third graders). Part 2 would cover the same things, but with college students. The results of retention were the same. They concluded that spaced repetition increases recall for anyone at any age.
Now moving to more modern times. In 2016, a researcher named Sean Kang would state that spaced practice can be a cost-effective approach to studying. This can be a little confusing at first, but he then explains that spaced repetition uses less time and yet shows greater results when it came down to retention.
Even further down the line, we would now use a more modern way of research and technology to see why spaced repetition really works. In 2019, a team of researchers at Beijing Normal University in China used scalp EEG data to get a picture of the biological basis for the effectiveness of spaced repetition.
They started by analyzing the scalp EEG data using spatiotemporal pattern similarity (STPS). This kind of analysis looks at specific information in a particular location over a certain time interval.
Using powerful technology, they were able to capture loads of data that revealed patterns in brain activity. The technological analysis showed that “greater item-specific STPS in the right frontal electrodes at 543–727 ms after stimulus onset was associated with better memory performance.”
In simpler terms, spaced repetition is directly associated with better memory performance (through science).
Today, the renowned method of Spaced Repetition just might be the greatest memory enhancer we’ve seen yet.