How to always remember what you learn

Repetitio est mater studiorum. Repetition is the mother of learning.

Things that don't get repeated, will be forgotten. We’ve all noticed this in our lives. We can forget a song we used to play on an instrument, the name of a bird we learned in school, a password we haven't used in a long time, and countless other things.

But there are things we haven't forgotten and won't forget, such as the capital city of country, our address, our phone number, etc.

The knowledge we use and repeat will stay in our memory, while the rest will be gradually forgotten.

Repetition is therefore an important part of memory and learning. The problem arises in deciding when to repeat the material and when to take on new material. The answer to this lies in spaced repetition.

What is spaced repetition?

In 1885, Hermann Ebbinghaus published an article in which he presented the forgetting curve.

The forgetting curve describes how we forget what we have learned over time. He found that forgetting is fastest right after we learn something. After a few days, most of the information is already forgotten. In his research, Ebbinghaus discovered another important fact. If we repeat the material, the forgetting curve becomes more gradual. This means that we forget things more slowly. Since we forget more slowly, we can increase the time between repetitions. These two insights opened the door to the idea of spaced repetition.

The essence of this idea is that we repeat information just before we would forget it. This way, we don't waste time repeating fresh data that we won't forget, but only focus on the data that we would forget otherwise. We then repeat what we have learned to refresh it in our memory, while at the same time changing the forgetting curve - repeated information is slower to forget. With each successful repetition, we can extend the time until the next one. At first, we may need to repeat the material after one day, then after six, after 16, until it is so imprinted in our memory that we can refresh the data only once every few months.

We can approach spaced repetition in various ways, but the easiest is to use a program that is designed for it. We use Anki for learning new information and would recommend it to anyone.