General principles of the SuperMemo method

The main advantage you will find in SuperMemo that puts it apart from other hypermedia authoring tools is that it makes possible for you to use a speed-learning technique called SuperMemo. This technique was developed in Poland in the 1980s, and has become the main competitive advantage of software produced at SuperMemo World since 1991.

As you will have to wait a few weeks before you see the first effects of using the SuperMemo technology, please read the following paragraph to understand what SuperMemo is, and why it is worth a dose of your persistence.

Every student knows from his own experience that, after a period of learning, forgetting can ruin even the most meticulously woven structure of the learned knowledge. The obvious remedy against forgetting is repetition. However, repetition is time consuming. In the face of an increasing pressure to learn more and faster, most of the students on this planet waste a great deal of their life for learning things they are bound to forget. Ask a recent graduate about the proportion of the learned knowledge that he or she has retained in his or her brain after a 4-6 year course of studies. If the number produced is greater than 5%, it may only be attributed to the student's poor understanding of the devastating power of forgetting. Indeed, forgetting can ruin lives and careers, it inhibits progress of sciences, medicine, technology and all other branches of human activity where knowledge plays a part.

There is, however, a partial solution to the problem of forgetting: SuperMemo. The solution is partial, because it does not allow you to learn with no effort at all. However, it can be demonstrated in strictly scientific terms that SuperMemo helps you increase the speed of learning manifold. Indeed, it makes it possible to closely approach the maximum natural capability of the human brain to store and retain information. Over a lifetime, SuperMemo allows you to learn 10-50 times faster than by conventional methods, and to reach knowledge retention rates of 95% or more. How about gaining the level of knowledge of an experienced professor in just a few years?

SuperMemo minimizes the effects of forgetting and the overall time needed for learning. This is done by scheduling repetitions of knowledge items in carefully determined intervals of time called optimal intervals. These are calculated on the basis of two contradictory criteria:

* Intervals should be as long as possible to obtain the minimum frequency of repetitions, and to make the best use of the so-called spacing effect, which says that longer inter-repetition intervals, up to a certain limit, produce better memories

* Intervals should be short enough to ensure that the knowledge is still remembered.

In practice, these two criteria translate into the following one:

Intervals should be as long as it is necessary for a selected, small fraction of knowledge to be forgotten. This fraction, called the forgetting index, can vary from 3%, for slower and very exact learning, to 20% for blitz-learning characterized by lower knowledge retention.

If the forgetting index drops below 3%, the knowledge acquisition rate becomes unacceptably low. On the other hand, the acquisition rate peaks at the forgetting index of about 20%. Above that value, both the retention and acquisition rate decrease. Note, that one can compare traditional learning, in which repetitions are arbitrarily set in time, to time-optimized learning with the forgetting index above 50%. Such learning is not only slow, but above all, the retention of knowledge may be unacceptably low, and in consequence, instead of remembering things which are important, the student remembers only things which are easy to remember.

As optimal intervals differ for particular facts or rules that are to be remembered, SuperMemo requires that the learned knowledge be split into smallest possible pieces called items. If items were to be repeated collectively, e.g., as chapters of a textbook in traditional learning, the overall optimal intervals would have to be as short as the optimal intervals for the most difficult subitem in the set. This would make learning even less effective than learning by means of classical methods. Splitting knowledge to small pieces makes it possible for SuperMemo to determine an independent repetition spacing for each of the items.

Simplicity of items is perhaps even more important for cytophysiological reasons. Simple items make it possible for the right neuronal synapses to be fully stimulated at the right time. Complex items result in trains of diversified nervous impulses that result in unpredictably intricate molecular memory patterns, which make optimization of repetition spacing difficult or not possible at all.

Optimum repetition spacing and simplicity of items are a formula for speed and high retention. However, the speed of learning is not the most important element of education. It is the quality of knowledge and its representation that count most. SuperMemo allows you to learn very fast, but it is still your responsibility to select the learned material and represent it in the most suitable form.


1. The key to effective learning is in minimizing the number of repetitions necessary to maintain knowledge in the brain.

2. SuperMemo optimizes the process of learning by approximating optimal intervals that should separate repetitions of knowledge.

3. The knowledge memorized by means of SuperMemo must be split into smallest possible pieces called items.

4. Applying SuperMemo, one must not forget that the quality of learning will depend on selection of the learned material and the way it is split into items.

For some popular scientific insight into SuperMemo see:

Theoretical background of SuperMemo

Scientific conquest of the forgetful memory

If you are not scared by mathematics, you can find out more about SuperMemo optimization algorithm used in spacing repetitions. If you would like your application to use the SuperMemo method, read about SM8OPT.DLL.