The Heart of an Elephant

Memorization is a necessary evil of the modern education system. Unless your field of studies is highly focused on hard sciences, chances are passing on your exams depends on memorizing certain sets of facts, dates, figures or processes.

Memorization is everywhere. Medicine students need to memorize insertions, drugs and symptoms. Law students need to memorize laws and their implications. Psychology students need to memorize and talk about theories from famous psychologists. Biology students need to memorize structures of plants or animals specific to several different phyla or classes.

Easier said than done. Studying vast bodies of knowledge over a limited period of time is difficult and mentally strenuous.  It requires total focus for hours on end, which can prove difficult when multiplied by several subjects in one semester.

I’m sure that during some boring study session for the 4th exam of the semester you wondered, why do we forget? Why can’t we just remember everything we read?

memory formation

Scumbag Brain

During a normal day, most of the information we’re exposed to is useless. I bet you can’t remember the color of the shirt your Math teacher was wearing a week ago. No one cares, our brains can’t be overwhelmed by those kinds of details.

However, our brains will immediately store information in the long-term memory store if the data obeys some rules:

  • Repetition, i.e. your teacher wore the same shirt every single day for a year.
  • Uniqueness, i.e. your teacher wore a Mickey Mouse shirt several times during the school year.
  • Connection, i.e. your teacher was using the same exact shirt your father used to when you were little.
  • Motivation, i.e. you were particularly interested in the shirt your teacher had on, because you were investigating her as the main suspect for stealing food from the Student Lounge.

Among those 4 factors, repetition is definitely the most important. Repetition helps not only form new memories but keeping them from being forgotten after a few hours, days or weeks.


This graph shows how quickly we forget what we read after only a few minutes. 20 minutes after the first contact with information, the subject forgot 40% of the total content. 9 hours afterwards, more than 60% was gone from his hippocampus (the region of the brain that holds your memories).

Fortunately, there’s a simple method to fight against forgetting – reviewing. The more times you review the same set of facts, the longer it will take to forget them. Evidently, reviewing the material 3 times will delay the loss of memory significantly when compared with someone who reviewed once or twice.

But if reviewing is an effective way to make newly formed memories stick around, there’s an interesting question we may ask ourselves: how often should reviews take place?

Should you review the same content every day? Or perhaps wait a few more days in order to spend less time with the same content? Is one week too much or too little?

These questions are simply answered with one awesome studying technique: Spaced Repetition.

The Miracle of Spaced Repetition

Simply put, spaced repetition consists in reviewing a given set of facts between gradually increasing intervals of time. It works best for content in the form of Question-Answer, like “What’s the capital of Somalia? Mogadishu”, “What’s the function of Pectoralis Major? Flexion and abduction of the humerus”, “What’s the atomic number of Iron? 26”.

Let’s say you were studying all of the world’s capitals:

  • Day 0: You learn 10 capitals you didn’t know before. This step can be done without Spaced Repetition.
  • Day 1: You review those 10 capitals for the first time.
  • Day 3: You review them for a second time.
  • Day 6: Third review.
  • Day 10: Fourth review. And so on.
  • If you fail to remember a certain card, go back to day 1.

This method is based on solid science, namely a psychological principle known as the spacing effect – items that you frequently review are easier to remember.

Spaced Repetition is great because it adapts to the learner. If you’re having trouble remembering certain items, you’ll repeat them more often, while easier items will not show up as frequently. These intervals are usually computed by an equation just like this one:

In which I(n) is the interval based on the number of reviews and EF is an estimated difficulty factor. Luckily, software magic does most of the heavy lifting, otherwise employing this method would be too complex.


The most famous program to learn via spaced repetition is called Anki, a free Windows and Android app that allows everyone to create flashcard decks and study them with spaced repetition. You can even download existing decks created by the community, some of them are incredibly well done.

Anki also allows the users to create specific types of cards:

  • Cards with images or sounds: great for language learning, in order to create visual or auditory connections between words and the concepts they represent.
  • Double sided cards: you can be shown both sides of the card and be asked what’s on the other side. For example: “What is H2O?” – “Water” and “What’s the chemical symbol of water?” – “H2O”
  • Fill-in the blanks cards: shows an incomplete sentence that has to be completed with data from your memory, e.g. “The man landed on the Moon in […]” – “The man landed on the moon in 1969”.
  • Typed answers: Anki will ask you to type the answer and then compare it with the original text on the card.

Creating quality cards depends, to a certain extent, on the creativity of the user. Think about how you can elicit maximum recall from your cards and how they can help your memories stick.

My personal experience with Spaced Repetition has been extremely positive and I couldn’t recommend it more. I learned Swedish fairly quickly using flashcards and also some basic German. As a medical student, Pharmacology, Surgery concepts and Anatomy become much less daunting when studying with flashcards.

It all boils down to the numbers. For example, if you have to memorize 500 anatomy concepts for a test (including names, insertions, functions, etc), divide those 500 by 20 concepts a day and you get 25 days. Under less than a month, you’re able to learn 20 new anatomy concepts a day without forgetting the ones from previous days – game-changer.


Spaced repetition works great every time you need to memorize large sets of material over an extended period of time. It’s not a cramming tool, but will ensure that what you study with it keeps inside your brain for a long time. Smartphones allow thousands of flashcards to fit in your pocket and be easily studied anywhere. With a little help from software, there’s no better time to take advantage of this resource.

However, it does require serious commitment to what you are learning. Failing to study every day will cause the cards to pile up. If you had 100 cards to review in a given day and you forget about it, expect to review 175 cards the next day. Moreover, spaced repetition is a learning tool, but not exactly a comprehension tool. It’s best used after you clearly understand the concepts, not as a standalone learning tool.

All in all, I don’t know of any method as efficient as Spaced Repetition when it comes to memorizing. While designing your own cards and maintaining the discipline required to study every day is difficult, the rewards are Matrix like absorption of information.

John Ramos

Author John Ramos

A medical student, entrepreneur and Science enthusiast. When outside the gym, hospital or conference halls, John does his best to keep up and running.

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