The Forgetting Curve by Ebbinghaus – Why do we forget new knowledge so quickly?

How much do you remember the content of the last book you read?

We can argue about the exact number, but the percentage is probably rather low.

The reason we forget is that our brains are designed for efficiency. Things that seem to be unimportant are quickly forgotten again, and, unfortunately, most things are not deemed important by our brains.

The rate of forgetting

The rate of forgetting is described by the forgetting curve.

It was first discovered in 1885 by the German psychologist Hermann Ebbinghaus.

In this article, I will show you why we forget things, how the forgetting curve is structured and how you can use targeted repetitions (spacing effect) to build up a personal store of knowledge so that you finally keep all the important facts in your head.

I often think to myself that I have a memory like a sieve: the only comfort I have is that I’m not the only one with this problem. Most people suffer from the fact that they immediately forget facts they have learned.

But instead of trying to find a real solution for this problem, they try to rely on cramming (bulimia learning) for learning new knowledge.

I also went down this path.

At least it made me graduate from school and university. However, if you ask me today about the knowledge I have retained from these years, you will quickly realize that just a few facts have stuck with me.

Our brain always forgets

But that’s not necessarily a bad thing.

Our brain constantly cleans itself up, by keeping just the information that is really important for our life.

That’s why things stick better that really interest us, that touch us emotionally or that simply play an important role in our day-to-day routine.

And if you forget knowledge, that doesn’t mean you’ve lost it forever.

It seems that every bit of information we’ve ever taken in is stored in our heads. We only need a key to retrieve them. This can be done by linking things that are related to each other.

For example, you can probably easily remember what you did on the day of your friend’s wedding, but it is much harder to remember anything if you don’t have a shortcut to this day.

What did we do on July 4th, 2017? You will probably have no idea because you don’t have any saved links to this date.

However, if you ask people who have consciously experienced days like September 11, 2001, they can almost always remember unimportant things that they did on that day.

The emotional event is the link to all other memories associated with it.

Learn smarter, not harder

In order to stop forgetting try converting dry dry facts into pictures and emotions. This hack is used by mnemonics as the loci method or the major system.

The problem with these methods is that setting them up is relatively time-consuming. In addition, mnemonics do not stop the forgetting process: the information simply stays longer in your brain because stronger neuronal connections are established.

But if you neglect your memory palace for some time, you will nonetheless have difficulty finding the stored information.

I am a big fan of mnemonics and they are also the reason why I got into memory training and learning methods in the first place. However, they are not a panacea when it comes to acquiring knowledge over the long term.

So, for a long time, I simply tried to store new knowledge in such a way that I could quickly access it again.

Mainly, with the Zettelkasten methode.

However, while some people argue that remembering facts is not the most important skill in today’s world, where all the world’s knowledge is at our fingertip, others point out that facts work as a kind of knowledge framework. This framework enables us to combine different ideas and come up with creative solutions.

So, I was delighted when two years ago I stumbled over a method called Spaced Repetitions.

Spaced repetitions make use of the forgetting curve, the rate of forgetting that occurs in our brain. This way, we can retain almost 100% of everything we try to remember.

How to use the forgetting curve to learn?

Our brain deals with new information in the following way:

We do not forget information linearly, but exponentially: The greatest loss of knowledge occurs within the first few minutes. Then the curve slowly flattens out. On average, half of the facts learned have disappeared after half an hour.

And so it goes: Each new piece of information has a half-life of 30 minutes. After 6 days we can only remember 23% of the learning material. In the long term, on average only 15% of the learned facts remain stored in the brain. Unfortunately, we can’t choose which facts will belong to this 15%. (source: Stangl).

The course of this forgetting curve was first presented by the German psychologist Hermann Ebbinghaus. He tested his memory by learning lists of meaningless syllables (e.g. according to Wikipedia: pöt, tuv or zim) and then checked how quickly he forgot the learned syllables. He was able to prove the exponential course of forgetting, as shown in the following graphic:

According to Ebbinghaus, people forget new knowledge with a half-life of 30 minutes. At least that explained why so many people feel like they have a sieve in their heads. This exploration was a milestone, and when s Ebbinghaus also discovered the Spacjing Effect, he solved the problem of forgetting.

The Spacing Effect

When Ebbinghaus repeated his list of meaningless syllables the following day, he could memorize them with significantly less learning time. After each repetition, he was able to increase the distance between the repetitions in order to achieve the same learning success (the distance between the necessary repetitions also grows exponentially).

This is the Spacing Effect.

To make use of this effect, it is only necessary to determine the optimal time interval between learning the subject matter, the first repetition of the subject matter, and the dates of each additional repetition.

Calculating this yourself for every piece of knowledge you are learning would be a cumbersome approach.

Fortunately, it is possible to determine the repetition intervals using an algorithm. Educational software has been available since the 1980s that tries to determine exactly that. It all started with the Supermemo program by the Polish researcher Dr. Piotr Wozniak. Much better known today (especially among law and medical students) is the open-source software Anki.

Here’s how Anki and Supermemo help you study

Learning software such as Anki or Supermemo uses an algorithm to try to determine the correct repetition period.

If you learn a new Anki flashcard, it will be shown to you again after one day. If you can recall it on the first repetition, the interval increases (the distance depends on whether you found the answer difficult or easy). If you can’t remember, you’ll have to do it again the next day.

The Anki algorithm is certainly not 100% perfect and a huge portion of the users don’t use the software correctly: they might regularly skip repeat days, or indicate that the answer was easy for them even though they had trouble answering it, and so on. Nevertheless, with the help of Anki you can retain new knowledge much more efficiently and keep it in your brain long-term.

Anki now serves as my personal knowledge repository: whether it’s information from books, blogs, YouTube videos, or lectures, as soon as I think the knowledge is useful for me in the future, it goes into my Anki flashcard stack. That way, as long as I do my Anki reps for a few minutes each day, I can be sure to remember it later.

That’s also the only problem with learning with Anki: If you want to keep knowledge for a lifetime and not just until the next exam, it has to be repeated for a lifetime. However, that sounds more strenuous than it really is: after just a few successful repetitions, the interval until the next repetition is several years. If you don’t add new knowledge to your Anki stack, you’ll soon be left with little to do.

In my experience, most people take a different route and add new knowledge far too quickly and on a far too large scale.

If you overwhelm yourself, you can quickly get an Anki burnout and leave things as they are. So that you don’t make the same mistake,

Spaced Repetitions for Notion

Recently, I have built a Spaced Repetition Solution for Notion. Check out my article to learn how to implement it into your Notion workspace.