In recent years, the use of mnemonic strategies has become popular and systematic, allowing very complex information to be learned in relatively simple ways. Among these techniques, the loci method, the hanger method, the memory palace or spaced repetition stand out.

In this article we will describe the spacing technique and explain how to apply it to memorise large amounts of information. We will also talk about the effect of spaced memory, a psychological phenomenon that explains the effectiveness of this mnemonic.

What is spaced repetition?

Spaced repetition, also known as spaced review, is a rote learning technique that consists of learning a given material by allowing increasingly long periods of time to pass between one training session and the next.

This technique is used to memorize content and practice skills over time, rather than intensively for a short period of time. The space between training sessions increases progressively as the learning process solidifies in order to use the spaced memory effect, which we will discuss later.

This spacing of learning allows for greater maintenance of memory: each time the memorization exercises are practiced, a new review of the information being worked on is carried out. Even intensive learning tends to be maintained to a lesser extent if regular practice is not carried out later.

Spaced repetition is especially useful when you intend to memorize a large number of different elements permanently. Examples include mathematical formulas or the vocabulary of a foreign language.

Likewise, the advances that have taken place in recent decades in the field of computing have favoured the emergence of computer-assisted learning methods. Many of these are based on the technique of spaced review, or allow it to be easily applied.

The spaced memory effect

Hermann Ebbinghaus, a pioneer in the experimental study of memory who lived in the second half of the 19th century, described two phenomena that gave him a place in the history of psychology: the forgetting curve, which represents the duration of memory strokes if no subsequent learning review is applied, and the effect of spaced memory.

According to Ebbinghaus and other later authors, when learning is distributed over time the information is retained better than if it is carried out in a single session. In the first case we talk about spaced presentation of the content, and in the second case we talk about massive presentation.

This implies, for example, that if we study for 6 hours for an exam the night before it, after a few days or a few weeks we will have forgotten a greater proportion of what we learned than if we had spread those 6 hours over several days. However, the superiority of spaced learning is not so clear in the short term.

There are different hypotheses about the causes of this effect; all of them may be true in relation to different types of learning and information retrieval (such as free and clueless recall). In this sense , the phenomena of semantic priming and neuronal enhancement in the long term stand out.

How is this technique used?

The most common method of applying the spaced repetition technique starts by dividing the information into small blocks of content. In some cases this is simpler than in others; for example, vocabulary can be studied using short definitions, but to memorize historical episodes it will be necessary to outline or summarize the information.

It is necessary to understand the content you want to memorize before preparing the training ; this will facilitate the capture of the relationships between the different elements and avoid possible errors in the preparation of the learning material. It is also advisable to divide the information as much as possible to facilitate the retention of each element.

Then the elements to be learned must be distributed in some kind of physical or virtual support. Cards can be used, but there is computer software that facilitates the use of spaced repetition, such as the Mnemosyne, Anki and Mnemodo applications. There are also specific programs for spaced language learning.

Two particularly popular types of cards are those that leave spaces to be filled in by the trainee (e.g. “Trigeminal is the _ of the 12 skull pairs”) and those that include a question and an answer. The latter can be prepared by writing a question on one side and a corresponding answer on the other side.

The time intervals between learning sessions and the length of the total learning period depend on the needs and preferences of the person applying the technique. The most important thing to bear in mind is that the memorisation exercises should be more frequent at the beginning and spaced progressively until the learning reaches the desired level.