Memory

Your IQ does not really matter
Who learns faster: larks or owls?
It is harder to learn foreign languages after forty
There is a physical limitation on how much we can learn per day
We remember pictures better than words
Forgetting is a decay process that can wipe out memories for good
Memorization allows of employing associational thinking
The main myth to clear out: Easy learning in Relaxation
Maximum speed of learning is not what you really need!
Reading also involves active recall
Putting things in the same place is a good idea
To memorize names, combine mnemonic techniques with spaced repetition
Submitting to your natural sleeping rhythm seems best for learning
Herbert Simon guess on the expert memory power reflects his genius
Polyphasic sleep can hurt your learning
Poor memory is usually a self-imposed limitation
Spacing effect results from reduced potential for increasing synaptic strength
Automaticity does not correlate with the probability of forgetting
Mixing declarative and procedural learning may be good for you
Ages old techniques are still valid
Your own personalized peg-list would work best
What kind of music is best for remembering?
Why do synapses get weaker during sleep?

SuperMemo

You need repetitions to remember for ever
SuperMemo may indeed improve your memory
If you want to devour books ... you will love SuperMemo
Going to a medical school? SuperMemo is a must!
We believe SuperMemo is a must for anyone with serious plans to enter science
SuperMemo can make you more creative!
SuperMemo can lead to learning garbage
Music and incremental reading
You can easily learn 10,000 items per year
SuperMemo accelerates learning 50-fold?
Who memorized most items with SuperMemo? 
SuperMemo is vital if you are dealing with large bodies of knowledge
The effectiveness of passive review may be dismal
If you have problems with focusing on repetitions ... you may be getting nowhere 
SuperMemo discourages mindless memorization
Does not minimum information principle contradict the need for associative knowledge
Bahrick's research on Spanish vocabulary retention does not undermine SuperMemo
SuperMemo can also be used for cramming
Why is SuperMemo slow to show its strength?
8-year olds are using SuperMemo with success
SuperMemo contributes to rat race!
Can SuperMemo be used to forget things?
Questions and answers might be enough for effective learning
Does SuperMemo use short-term memory or long-term memory?
SuperMemo can help you remember things that you do not even store in SuperMemo!
Delayed repetitions in SuperMemo
Trust SuperMemo to save time
Can SuperMemo help patients with ADD (Attention Deficit Disorder)?
SuperMemo and Alzheimer's
SuperMemo and low self-esteem
Could SuperMemo become an unhealthy addiction?
SuperMemo will not help you bring things to mind without a trigger
I don't buy memory overload hypothesis in Alzheimer's
It is possible to roughly estimate the amount of time needed for learning a portion of material
Vacation may feel like "improving memory"
Is repetition the best way to remember?
Minimum information principle v.s. the length of "20 rules" article
There is no harm in "memorizing" things you already know
Users of SuperMemo 2 can be irritated!
No other software can match SuperMemo
Intervals are measured in circadian cycles
Advanced repetitions and the spacing effect
Learning to do calculations in memory
One of 1985 experiments was inconclusive
Spaced Application & Semantic Networks
Use Simulation to figure out the expected speed of learning
Memorizing instances of abstract cases is not a waste of time
Limited Postpone will not damage your learning process
First meaningful split into difficulty categories occurs at first repetition
The optimum number of repetitions will depend on numerous factors
SuperMemo should not be viewed as a cramming tool
SuperMemo does not use microspacing of repetitions
Forgetting curve for ill-formulated items is flattened
Flatter forgetting curve does not increase optimum interval
There is no remedy to interference
See also: FAQ: Learning with SuperMemo

SuperMemo Algorithm

Intervals used in SuperMemo are not optimum intervals!
Higher grades can produce shorter intervals
Even low forgetting index can produce long intervals
First repetition does not have to take place on the next day
Why isn't first repetition followed by interval=1?
Intervals are slightly randomized
The algorithm used in SuperMemo is not "fixed"
The more time you give to SuperMemo, the closer it will approximate your memory needs
SuperMemo contradicts some results reported by Tony Buzan
Grades in final drill do not affect the interval
Your response time does not matter
You can compute your retention from the forgetting index
Different intervals used in different SuperMemos
Use Simulation to estimate workload
SuperMemo ain't science! He just ad junk 
SuperMemo is better than re-wise
Mid-interval repetitions do not bias your measured forgetting index
Simulation of learning process in SuperMemo may be inaccurate 
Short-term memory requires no spaced repetition
Multitasking is not recommended in learning
Repetition category is used to update optimization matrices
First Grade vs. A-Factor graph data is kept as a collection of trailing averages

Speed-learning techniques

What is better: SuperMemo or MegaMemory?
What is better: SuperMemo or SuperLearning?
What is better: SuperMemo or Tony Buzan's mind-maps?
What is better: SuperMemo or NLP?
What is better: SuperMemo or VTrain
You can learn mind-maps with SuperMemo
Tony Buzan and SuperMemo
You can best remember mind-maps by ... splitting them to pieces
You can add a mind-map to the answer component
Memorizing mind-maps does not contradict minimum information principle
Memorizing collections such as 20x20 Multiplication Table increases mnemonic computational skills
SAFMEDS skills are useful in incremental reading
The Silva method does not seem to be based on solid science
Mega Memory and SuperMemo are complementary
Mega Memory controversy
Axon software

Other

The term "staggered learning" may sometimes be used to describe "spaced learning"
Alarm clock may hurt your learning ability
You do not need more than one nap per day
Memory "overflow" is not "fatal"
Internet addiction falls out of this site's focus

See the body of this file for more answers

(Elena and Rachel, US, Dec 12, 1997)
Question:
How is SuperMemo supposed to improve someone's memory?
Answer:
We do not claim that SuperMemo improves memory. We say that it allows you to learn fast with high retention of knowledge. The fact is that improving your memory will be a nice side effect, but this will happen not by virtue of the SuperMemo method but by virtue of intense learning. SuperMemo makes it possible to learn fast by organizing your learning process. For more see: General principles of SuperMemo

(Crizeldo  G.  Cariaso, MD, Philippines, Dec 17, 1997)
Question:
I am a medical doctor who is into resident training as of this moment.  Do you advice me to use your product if I read about 100 pages of documents and books a day and have to remember it?
Answer:
Absolutely! Read Devouring knowledge to see how you can read thousands of independent articles at the same time. If you learning from paper books, your job will be much harder. You will only be able to remember a fraction of the material. An exemplary algorithm would be:

1. divide your time to: 70% reading, 30% SuperMemo 
2. in SuperMemo time slot formulate questions in reference to the most important facts and rules you have learned from the books. Memorize  those facts. Those shall stick to your memory for ever (if you regularly run repetitions as scheduled by the program)

The sad fact is that reading 100 pages daily is really a feat, and even the mere typing in the material to SuperMemo will limit you to 20-100 questions per day (depending on time available and the speed of typing). Even this small proportion will still provide you with amazing build-up of knowledge! It is very important that you intelligently select what must and what does not have to be memorized

(Tomasz Szynalski, Poland, Oct 18, 1998)
Question:
What value of the forgetting index ensures the optimum ratio of (retention)/(time spent per day)?
Answer:

Paradoxically, the highest speed of learning can be accomplished ... without SuperMemo! In our daily life we pick up lots of facts that stay in our memory for long with few repetitions in lifetime! The problem is that these are usually not exactly the facts or rules that are critical to our goals. In other words, not the speed of acquiring new items counts but the speed of acquiring new items bearing a given content.

It is difficult to determine exactly what forgetting index brings the highest acquisition rate. Simulation experiments have consistently pointed to the value of 25-30%. You can even plot speed-vs.-forgetting graph using your own actual learning material in SuperMemo 98 using Tools : Statistics : Simulation. You will probably also arrive to similar results

As you perhaps know, SuperMemo disallows of the forgetting index above 20%. This comes from the fact that you should aim at achieving high speed of learning combined with high retention of the learned material. Setting the forgetting index above 20% would be like giving up SuperMemo altogether and coming back to remembering only that what is easy to remember. In highly interlinked material where new knowledge depends on the previously acquired knowledge, high forgetting rate can even be more harmful

Nevertheless, if you want to maximize the speed of learning with little control over what actually stays in your memory, set the forgetting index to 20%

Question:
On what basis do you ground your claim that SuperMemo increases the speed of learning from 10-50 times?
Answer:
For knowledge retention of 95%, it can be computed that the number of repetitions in an average learning lifetime (i.e. about 55 years) is roughly 50 times greater for equally spaced repetitions than for progressive repetitions (as used in SuperMemo). For repetitions with no regular spacing scheme, this number may even be greater. Moreover, the greater the required knowledge retention, the greater the increase in the knowledge acquisition rate (classical forms of learning almost never reach knowledge retention above 10%!!!). In practice, users of SuperMemo claim that it increases their speed of learning from 50% to 2000%. These values are, however, highly subjective, as they do not account for so-called intractable items, which are practically not memorizable without SuperMemo. In other words, students tend to underestimate the fact that they reach knowledge retention from 90-99%, which would hardly be achievable using any other method.

(Jerzy Duda, Poland, Oct 1, 1997)
Question:
What is the lowest age at which a child can start using SuperMemo?
Answer:
The younger the child the more difficult the entry into the learning process. However, with a dose of parental guidance, even first-graders can cope with SuperMemo. The learning process itself is simple and repetitive and the child can quickly enter regular repetitions. Definitely, SuperMemo 98 (and later) at the beginner level is much less daunting than SuperMemo 7 for the initial entry. As a documented example, 9-year-old Agata Czaplinska from Gliwice, Poland, memorized 150 new English words in 2 months working nearly on her own. In another case, 8-year-old Annalynn Clary from Monroe, Louisiana (USA) memorized Cross Country material (1673 items) in 100 days working 30 minutes per day (5 days per week)

(Elena and Rachel, US, Dec 12, 1997)
Question:
Do people with higher IQ benefit more from SuperMemo?
Answer:
People with higher IQ are more likely to find clever uses for SuperMemo and they are usually faster to grasp the principles of the program. They are also more likely to become addicted to SuperMemo as one of their most important applications. However, recent research indicates no significant correlation between IQ and any of 30 major studied learning parameters used in SuperMemo

Mixing declarative and procedural learning may be good for you (#4331)
(Robyn, Tuesday, April 26, 2005 9:11 AM)
Question:
Has an interference effect been noted between declarative and procedural learning? If I immediately follow a Spanish lesson with a martial arts lesson, will consolidation of either be adversely effected?
Answer:
Declarative and procedural learning are governed by different brain circuits and even their consolidation in sleep seems to be separated in time. For that reason, interference between both is highly unlikely. At the same time, there could be positive trophic feedback between the two (i.e. learning in one circuit may have some positive effect on another). In other words, mixing Spanish and martial arts might be a very good strategy for enhanced learning. As for the optimum sequence, it is very difficult to determine. If your martial arts training is very intense, it might better follow Spanish due to possible physical exhaustion. On the other hand, if it is modestly stimulating, it could equally well be executed before. You could also split your Spanish into two portions and execute part of it before and part of it after the training. That could prevent the overload effect (mental tiring in prolonged learning). Your best strategy for determining the learning sequence would probably be to try what seems to work best for you

Question:
Why is the first interval after which the first repetition takes place not equal in all cases?
Answer:
It is randomly modified to speed up computing its optimal value. Additionally, random dispersion of intervals around the optimum value prevents repetitions from being packed on a given day, while neighboring days have lots of room to accommodate new items.

(Tomasz Szynalski, Poland, Oct 18, 1998)
Question:
What retention can I obtain with the forgetting index set to 9%? What if I then change it to 12%?
Answer:
The formula that relates the forgetting index to the retention looks like this (source):

retention = -(forgetting index)/ln(1-(forgetting index))

If you accomplish the forgetting index of 9%, the retention will equal 95.4%. For 12%, the same figure will be 93.9%. Note that if your material is very difficult, your measured forgetting index may be higher than the requested forgetting index. This comes from the fact that SuperMemo imposes some boundary conditions on the increase of intervals. Elements that have been forgotten more than five times should be reformulated with a view to reducing their difficulty or increasing their mnemonic component.

If you initially set the forgetting index to 9% and later on increase it to 12%, you will probably start with retention of 94-95% which will later gradually decrease to 92-93% (after the change)

(David Mckenzie, New Zealand, Apr 8, 1998)
Question:
Why does not the first repetition after forgetting occur the next day after the unsuccessful repetition (this is advised by Tony Buzan and others)?
Answer:
In SuperMemo, the length of the first interval is computed from the forgetting curve plotted in the course of repetitions. This is to make sure that a defined proportion of items is remembered (usually 80-97%). This proportion is programmed by means of the forgetting index. Depending on the forgetting index, the length of the first interval may range from 1 to 20 days, and is not set arbitrarily. It is computed from the record of repetitions and determined by the desired forgetting index (requested forgetting index is the proportion of items that are not remembered at repetitions). While Buzan’s recommendation is valid in many cases, you should not forget that SuperMemo computes intervals with a high degree of accuracy that cannot otherwise be easily achieved

(Constantin Ilieu, Bulgaria, 1993)
Question:
In your materials I found a contradiction. On one hand you claim that once learned knowledge is constantly maintained in the student's memory, on the other you say that after ceasing repetitions, I will gradually forget what I have learnt. Which is true?
Answer:
Both facts are true. The term maintained is understood as kept in memory by means of repetitions, not as remains in memory for ever

(Manfred Kremer, Germany, Sep 7, 1998)
Question:
I noticed that frequently I get Optimum Interval in Element Data window shorter than the last interval displayed as Interval. Is it a bug in SuperMemo?
Answer:
No. If your forgetting index is very low, e.g. 3%, SuperMemo will often conclude that you will stand 97% chance of remembering a given element only if your next interval is shorter than the presently used one. In such cases, it will not accept the new value and the new interval will be at least 5% longer than the previous interval. Please note that the forgetting index equal 3% should only be used for selected high-priority items. Keeping the forgetting index at this level throughout the collection will make repetitions annoying frequent and ineffective

(Ryszard Siwczyk, Poland, Nov 4, 1997), Poland, Nov 4, 1997)
Question:
Does the response time at repetitions influence the next interval?
Answer:
No. Repetition timer is only used to compute the average response time and Workload.

Polyphasic sleep can hurt your learning
(Mariusz Zmuda, Poland, March 22, 2000)
Question:
Is it true that it is better to get shorter sleep in the night and then take a few naps during the day?
Answer:
This approach is not likely to benefit your health or learning. Most of all, you should not artificially shorten the night sleep! As for the naps, in healthy adults there is only one major trough in alertness during the day at siesta time. Taking more than one nap is not likely to be needed. Experts on insomnia argue against naps as these may keep people up at night. If your nap lasts only 5-45 minutes and does not affect your ability to fall asleep in the night, it will help you stay more alert in the evening hours. See: The cruel myth of polyphasic sleep and Good sleep for good learning

(Grzegorz Malewski, Poland, Dec 10, 1997)
Question:
Do grades at final drill affect the learning process?
Answer:
No. They are only used to eliminate items from the final drill queue.

(Spud Science, USA, Feb 14, 1998)
Question:
What is the best (most effective) way to set up a new series of question and answer pairs in SuperMemo?
Answer:
See: 20 rules of formulating knowledge. See also: SuperMemo Decalog. For a more academic reading in the subject you can have a look at Knowledge Structuring and Representation...

(Matt Cassidy, New Zealand, Sep 11, 1997)
Question:
Is it possible that with forgetting index equal to 3% I get the first interval equal to 6 days?
Answer:
Yes. Especially if the material you work with is relatively easy. You should also remember about random dispersion of intervals. In isolated cases, dispersion might produce intervals substantially longer (or shorter) than the optimum interval. For more read about SuperMemo Algorithm

(Jake White, USA, May 14, 1997)
Question:
Should not final drill continue keeping a queue of no less than 10 newly learned words in order to make sure that when repeated again and again they will really be imprinted well in short-term memory.
Answer:
This solution may indeed eliminate contextual dependency in final drill (remembering items only because of having them in a given context); however, this would involve lots of extra repetitions that would contradict the principle of SuperMemo: maximum effect at minimum time. Additionally, the learner would risk activating the spacing effect, i.e. reducing the probability of recall as a result of excessive repetition! The best solution to contextual dependency is (1) random shuffling of final drill queue with Tools : Randomize : Drill and (2) concentration (not grading well items that were remembered only due to appearing in a given context).

Question:
I have heard that baroque music is the best for improving memory; particularly Bach and Vivaldi. Does it also work in association with SuperMemo?
Answer:
The claim that any particular kind of music is best for memory is unlikely to be true. Indeed, music can have powerful impact on our emotions and, consequently, on remembering. It has been found that it is similar in effects to caffeine. However, a study that measures impact of a particular kind of music on recall in a group of people can be compared to trying to find the optimum size of a shoe for an average citizen. Depending on the musical education of an individual, the same kind of music may bring a variety of emotion from relaxation, through agitation to aggression. While Four Seasons may have a positive impact on the mind of majority of the population, the best bet would be that everyone should stick with the music he or she likes. Be it punk or funk. The truth is that all that is good for the mind and health is good for remembering.

(Miss E216, US, Nov 25, 1997)
Question:
We are 7-th graders and work on a project related to memory. We have a question to Dr Wozniak: "Why do we better remember pictures than word combinations?"
Answer:
In the course of evolution, humans practiced visual memory a lot. They did not deal much with math or abstractions. That is why there are parts of our brain built specially to serve visual memory. As you know, evolution gives better adapted individuals a better chance for survival. Those who could remember better, e.g. shape of the prey or enemy, could survive better, and pass their "good" genes to the next generation. Calculating a differential was not needed in apes or early humans. That is why evolution did not built a specialized calculator into our brain. It has, however, built a calculator for processing visual data. You "type in" the picture, and get a short answer: "danger!" or "food!". Those simple signals are easier to remember than ... streams of bits of a complex image. Evolution and memory are fun, aren't they.

Question:
Can I use SuperMemo to memorize mind maps?
Answer:
Yes. You can build mind maps directly in SuperMemo; however, it is easier to import them from specialized mind map software (e.g. MindMan). You can include MindMap objects with the OLE component or you can simply import them as graphics (as BMP or GIF files).

For example, import your mind map as graphics to an image component and check Answer on the image component menu. Add a text component, e.g. "What is the structure of mind map X?".
During repetitions grade yourself less than Pass (3) each time your forget any part of the mind map! Do not forget that you should reinforce "weak links" in the mind map with separately formulated items of simple question-answer or question-picture form. Each time you forget part of the mind map, see if you have reinforced the forgotten links in separate items!

(Julien Seetharamdoo, UK, Jan 3, 1997)
Question:
I would like to know how to memorise mind maps?
Answer:
The best method is to split the mind-map into simple individual pieces and memorize these pieces separately! The pieces must be chosen in such a way that ensuring that you remember all of them you can guarantee that you can recall the whole map. You can find more information about this in knowledge structuring in repetition spacing

(Julien Seetharamdoo, UK, Feb 19, 1998)
Question:
I am trying to use SuperMemo 8 to learn mind maps created using Mind Manager. I have imported the mind maps as BMP files to the image registry but haven't been able to append them as answers to questions. How do I do this?
Answer:
It is faster to import files directly to image components:

1. Create an image component in the element window
2. Use Import file to import the BMP file (right click to open the pop-up menu with Import file).
3. Check Answer on the component menu to make sure that the image is not visible at question time.

NB: If you already have images in the registry, you can use Link Registry Member on the image component menu (instead of Import file).

Question:
Isn't memorizing mind maps in opposition to the minimum information principle?
Answer:
No. Minimum information principle should not be interpreted as minimum information on the screen, or minimum number of bytes to represent the item. It should be interpreted in terms of information that has to be stored in your memory. If you produce and item that links the image of a horse and a cow, the association is very simple. No mater how intricate the pictures of the horse and the cow are. The essence of mind maps is that they are easy to remember, i.e. if well-designed, they comply excellently with the minimum information principle.

Question:
Which learning method is more effective: traditional SuperMemo with questions and answers, or the new hypermedia SuperMemo with videos, games, puzzles, and tests?
Answer:
Simple questions and answers are extremely effective and easy to create; however, some users find classic SuperMemo too boring. If the psychological factor plays a part, the variety provided by SuperMemo 8 may substantially add to the effectiveness of learning. The answer to the question will depend on the application domain and the mentality of the student.

(Elena and Rachel, US, Dec 12, 1997)
Question:
Does SuperMemo improve short-term memory or long-term memory?
Answer:
SuperMemo builds up long-term memory but helps you increase your mnemonic skills that will result in the impression that your short-term memory works better.
You can also look at this like that: SuperMemo loads knowledge to short-term memory and this is transferred to long-term memory. The effect on long-term memory is stable but the speed of putting things into short-term memory may increase due to training. Short-term memory improvement comes slowly with training, but long-term memory build-up comes immediately upon employing SuperMemo!

One of 1985 experiments was inconclusive
(Tomasz P. Szynalski, Saturday, August 04, 2001 1:33 PM)
Question:
I see that one of early experiments showed that constant 18-day intervals were better than increasing intervals. So how does this prove the validity of SuperMemo?
Answer:
This 1985 experiment does not prove validity of SuperMemo. Nor does it disprove it. In that respect, it is simply inconclusive. The experiment was an attempt to "guess" optimum increase in intervals and the guess appeared wrong. If the underlying hypothesis was that increasing intervals are always better than equally distributed intervals, then this experiment proved that hypothesis wrong. Obviously, if equal intervals are short enough or the increase in the length of intervals is too fast, equal-interval schedule may appear superior. This is why, in the long run, we need to use a computer to optimally adjust the repetition schedule to the defined level of knowledge retention

(Prof. Witold Abramowicz, Poland, Feb 1993)
Question:
Does the minimum information principle not stand in conflict with the ages old rule that the learned knowledge should be highly associative in nature?
Answer:
No. The minimum information principles concerns the representation of knowledge in SuperMemo databases, not in the student's memory, and it does not prevent great advantages coming from proper structuring of the learned material. In the optimum situation, the student should first construct a cohesive model of the learned subject, and only then, apply SuperMemo to make sure that the learned knowledge is sustained in memory as a whole. The knowledge may be highly associative, but strictly targeted neural stimulation, achieved by means of granular representation of knowledge in SuperMemo, is necessary to effectively induce molecular processes responsible for memory formation. Indeed SuperMemo has been conceived in such a was so as to make it easier to formulate knowledge in a structured way (topics) and later learn it in a way typical for SuperMemo (items). See also: Topics vs items

(Anatolyi Lipatov, Ukraine, Jul 12, 1998)
Question:
I am using Advanced English to enhance my English and business English. Now I am registering for CFA examination (that is Chartered Financial Analyst program of Association of Investment Management and Research). There are several organizations developing and distributing methodological stuff for preparing to the exam. A lot of things should be memorized for passing the exam. What do you think the best way to fit SuperMemo for memorization and what approach should I use to prepare my own knowledge base for memorizing the material. Is special programming knowledge needed for it?
Answer:
No specialist knowledge is needed to prepare simple learning material collection in SuperMemo. With Alt+A (i.e. Add new) you get 90% of functionality! All advanced editing options can be worked around by an appropriate questions-and-answer approach. Perhaps it would be useful yet to learn how to add images to your items (see help for details). To learn more about effectively structuring knowledge in SuperMemo you might want to read 20 Rules of Formulating Knowledge and Knowledge Structuring and Representation; however, nothing works better as learning on one's own mistakes in formulating knowledge for learning with SuperMemo

(Pawel Dzierwa, Poland, June 3, 1997)
Question:
Personal question to Dr Wozniak: If you did not have SuperMemo at hand, which competitive product would you use?
Answer:
I would probably pick one of the programs that most closely follow the SuperMemo paradigm, e.g. Edukom or PowerMemo. Only later would I choose from better known products that are less focused on spaced repetition such as Langmaster or YDP's Collins Dictionary. However, as a software developer involved in the design and implementation of SuperMemo since 1987, I would rather opt for implementing the program from scratch. Back in 1987, the first version was written in 16 evenings. I would have to give up all the bells and whistles, but it is the core that matters most. And it would be most difficult to give up the control over what new options might yet be implemented

(Colin Quiney, Canada, Jan 22, 1998)
Question:
Do you think SuperMemo can be beneficial in patients with ADD (Attention Deficit Disorder)?
Answer:
User's ability to focus on repetitions is one of pre-conditions of success with SuperMemo. Seemingly, this would make ADD patients poor SuperMemo learners. Perhaps the report submitted by Maarten Mols from Holland sheds some different light on the issue: SuperMemo in a school for special education.

SuperMemo and Alzheimer's
(Maria Jonas, South Africa, Dec 2000)
Question:
Can SuperMemo be used in the treatment of Alzheimer's?
Answer:
Except for inconclusive anecdotal data, there has been no study of SuperMemo in Alzheimer's. See also: Can too much learning lead to Alzherimer's?

Question:
Tony Buzan claims that 75% of information is lost if not reviewed in 24 hours. Does it not defeat the validity of SuperMemo in which the first interval is often longer than a week?
Answer:
No. Buzan's claim may refer to textbook knowledge or complex knowledge structures (e.g. large mind maps). However, it does not seem accurate in reference to simple well-structured material in the light of results obtained with SuperMemo. In SuperMemo, if the student chooses the retention of 95%, the typical value of the first interval falls in the range 2-5 days depending on the student and the difficulty of the learned material. For retention 25%, the same interval might be as long as one month, though it cannot be verified experimentally with SuperMemo which limits the range of the forgetting index from 3-20%, which implies the overall retention in the range of 89-99%. For more see: Theoretical background of SuperMemo

(William McGhee, Jun 22, 1998)
Question:
Could SuperMemo be used to extinguish behaviours as well as reinforce them?
Answer:
Forgetting is a molecular process that cannot easily be induced by natural methods. The more so, there are no sensitive methods to induce selective forgetting, though lesion to some parts of the cerebral cortex may produce roughly localized amnesia. However, there is a component of forgetting that may be influenced. This component is interference. Whenever we learn new things, they always interfere with previously learned material. The interference may enhance some of memories while obliterating others. This fact can be used to employ SuperMemo in forgetting, by formulating and memorizing a large number of contradictory items that strongly interfere with remembered facts that are to be forgotten. For example, if you learn the meaning of the word "indict" and you want to later forget it, you might try to learn words like "indite" or some meaningless like "dictin", "incid", "endict", etc. However, you should not expect the effectiveness of such a procedure to be anything but disappointing.

Question:
I used SuperMemo 2 shareware, and was accustomed to repeating forgotten items on the next day. It is very irritating that in SuperMemo for Windows I do not have this possibility
Answer:
SuperMemo will schedule forgotten items in intervals that are determined by the forgetting index. The greatest increase in the speed of learning in newer versions of SuperMemo as compared with SuperMemo 2 resulted from substantially increasing the length of the first interval. The student may be left with the feeling that he is likely to forget the item again if it is not repeated on the next day. Statistically, however, he will forget no more than the proportion defined by the forgetting index (specified in Tools : Options : Learning : Forgetting index). By reducing the forgetting index to less than 5%, the length of the first interval is likely to drop to 1-2 days in most cases. Moreover, if you are particular about repeating a given item on the next day, you can choose Ctrl+M to commit or recommit an item with a selected first interval

Question:
I have an exam for a driver's license in 2 weeks. How can I best memorize the Traffic Regulations collection for SuperMemo? How can I increase the frequency of repetitions?
Answer:
Although SuperMemo is not a cramming tool, and it would be much safer to start 2-3 months before the exam, the following shall work pretty well: (1) Set Tools : Options : Learning : Forgetting index at 3%. (2) When memorizing difficult items, choose Ctrl+M and provide the first interval value equal to one day. (3) Memorize the collection in equal portions in the period spanning from today to 2-4 days before the exam. Use Tools : Random review intensely over the last 2-4 days

(Shaun Hoffland, UK, Oct 22, 1998)
Question:
Do you have statistics on what is the average number of items an average user has to repeat per day? What is the greatest number of memorized items?
Answer:
The best results oscillate around 60,000 items memorized overall, and 10,000 memorized within 4-5 months. Most users memorize 1000-10,000 items per year. Please read SuperMemo User Survey (esp. section Using SuperMemo)

(Scot Prohaska, USA, Oct 29, 1998)
Question:
I am going back to medical school after a 10-year break. I look for tools to improve my brain skills. Is SuperMemo a product for me?
Answer:
That's your lucky day! SuperMemo is ideally suited for enhancing your ability to learn new stuff and make sure it stays in your memory for good. Learning medical sciences with SuperMemo comes second in popularity to learning English! Recommended reading: Six steps to excellent memory

(Tomasz Szynalski, Poland, Oct 18, 1998)
Question:
When first versions of SuperMemo were released, how could SuperMemo predict intervals that were many years long if it had only been researched for a couple of years? I read that the first version was released after just 3-4 years of research on the length of intervals.
Answer:
The first experiments in reference to the length of optimum interval resulted in conclusions that made it possible to predict the most likely length of successive inter-repetition intervals without actually measuring retention beyond weeks! In short, it could be illustrated with the following reasoning, if the first months of research yielded the following optimum intervals: 1, 2, 4, 8, 16 and 32 days, you could with confidence hope that the successive intervals would increase by a factor of two. To better understand what reasoning lead to the first formulation of SuperMemo read: First experiments: 1982-1985

(Tomasz Szynalski, Poland, Oct 18, 1998)
Question:
What retention can I obtain with the forgetting index set to 9%? What if I then change it to 12%?
Answer:
The formula that relates the forgetting index to the retention looks like this (source):

retention = -(forgetting index)/ln(1-(forgetting index))

If you accomplish the forgetting index of 9%, the retention will equal 95.4%. For 12%, the same figure will be 93.9%. Note that if your material is very difficult, your measured forgetting index may be higher than the requested forgetting index. This comes from the fact that SuperMemo imposes some boundary conditions on the increase of intervals. Elements that have been forgotten more than five times should be reformulated with a view to reducing their difficulty or increasing their mnemonic component.

If you initially set the forgetting index to 9% and later on increase it to 12%, you will probably start with retention of 94-95% which will later gradually decrease to 92-93% (after the change)

(Tomasz Szynalski, Poland, Oct 18, 1998)
Question:
What value of the forgetting index ensures the optimum ratio of (retention)/(time spent per day)?
Answer:
Paradoxically, the highest speed of learning can be accomplished ... without SuperMemo! In our daily life we pick up lots of facts that stay in our memory for long with few repetitions in lifetime! The problem is that these are usually not exactly the facts or rules that are critical to our goals. In other words, not the speed of acquiring new items counts but the speed of acquiring new items bearing a given content.

It is difficult to determine exactly what forgetting index brings the highest acquisition rate. Simulation experiments have consistently pointed to the value of 25-30%. You can even plot speed-vs.-forgetting graph using your own actual learning material in SuperMemo 98 using Tools : Statistics : Simulation. You will probably also arrive to similar results

As you perhaps know, SuperMemo disallows of the forgetting index above 20%. This comes from the fact that you should aim at achieving high speed of learning combined with high retention of the learned material. Setting the forgetting index above 20% would be like giving up SuperMemo altogether and coming back to remembering only that what is easy to remember. In highly interlinked material where new knowledge depends on the previously acquired knowledge, high forgetting rate can even be more harmful

Nevertheless, if you want to maximize the speed of learning with little control over what actually stays in your memory, set the forgetting index to 20%

(Robert Szumilo, Poland, Jan 3, 1999)
Question:
What is the optimum approach to making repetitions with SuperMemo: one long session or a few smaller sessions (e.g. main repetitions in the morning and the final drill in the evening)?
Answer:
For psychological reasons, the quality of learning should increase substantially when working in separate sessions, esp. if the number of repetitions surpasses 100 per day. Additionally, a break before final drill is useful due to the spacing effect. The danger of this approach is ... you can easily drive yourself into a situation in which you will spend excessive proportion of your day on repetitions (in the future when your schedule changes you might have problems with keeping up with your present pace)

(Tony D'Angelo, USA, Feb 3, 1999)
Question:
I am a management consultant who uses professional development programs from a company called Resource Associates Corporation. These programs are based upon spaced repetition learning. In their literature they cite an unnamed study that suggests that people will generally only retain 2% of information they are exposed to in a one time event after 2 weeks. In contrast they suggest that at least 65% of information delivered over 5 consecutive days may be retained for 15 years to life. Can you confirm those claims?
Answer:
If you look at the graphs generated by SuperMemo during the learning process, you will notice that the 2% figure might be true depending on how the material has been presented and its difficulty. However, the claim that 65% of knowledge can be retained for 15 years as a result of five-day exposure must be false in the same light. Even if we consider perfectly formulated knowledge (i.e. knowledge characterized by the highest possible A-Factor), you might need to space the quoted five exposures in the period of 2-3 years to make the 65% figure realistic. If the quoted figures were accurate, you would probably never need to use SuperMemo! For more details on the speed of learning, see Theoretical aspects of SuperMemo

(Lawrence A. MacDonald, USA, Feb 16, 1999)
Question:
From your experience, and I know it is different with different people, how many repetitions (how far out on the scale in the future) does one need to make to have mastered in information, and what is the standard deviation for that number?
Answer:
There is no point when you can say the material is remembered for ever! Even after 20 years of repetitions there is a slight risk of forgetting. If you want to always remember a piece of information with a defined degree of probability, you should proceed with your repetition till your last day on this planet

(Lawrence A. MacDonald, USA, Feb 16, 1999)
Question:
What is the result on scheduling in the future when you add a question every day? At what point does your future schedule become vastly over booked?
Answer:
The beautiful thing about SuperMemo is that overbooking never happens! Your question and worry is typical for those who begin their work with SuperMemo. Please have a look at simulation experiments that show that the learning curve, in the long perspective, is nearly linear, i.e. it does not bend as a result of "overbooking"! In practice, you will be able to notice the decline in the speed of learning for no more than a year. Later the slowdown is minimum and entirely imperceptible! The mathematical explanation of this is quite complex. The measurements show that you spend 50% of time on just 2.5% of the material! Imagine then that the memorized material quickly reaches high intervals and disappears from view. You just constantly struggle with newly memorized items and items that you find difficult to remember

(Vit Usela, Czech Republic, Nov 2, 1999)
Question:
What do you think of so called memory-enhancing smartdrugs: Piracetamum, GABA, Vinpocetin, Takrin, Diapid, Vasopressin, Fipexid, Deprenyl, Hydergin, etc.?
Answer:
We do not take an official stand on memory enhancing drugs. Please consult other sources. Note the following though:

1. Forgetting has an important biological function and all attempts to prevent it by non-selective means are likely to result in information confusion described in some clinical case studies in psychiatry
2. Some of the drugs listed play an important physiological function and may be of value in learning for reasons other than memory enhancement. In this context you could always best consult your physician
3. Simple health-boosting factors such as exercise, healthy diet, sufficient amount of sleep and stress-management are likely to bring more benefit to your learning that all listed drugs taken together

(Tomasz Szkopek, Poland, Feb 25, 1999)
Question:
Does using SuperMemo increase the capacity of the human brain for learning with traditional methods?
Answer:
SuperMemo is likely to strengthen your mnemonic capacity. It is does not include any specific options for that purpose, it simply acts as a training tool via repetition. Your mnemonic techniques will develop subconsciously as a result of training the same way like muscles grow as a result of lifting weights. However, this should not be treated as a substitute for a course in mnemonic techniques. If you have not heard about mind maps and peg lists, you might want to visit sites listed in the links section (e.g. Buzan site).
Secondly, recent research shows that the brain continues growing new neurons and new synapses even at a very advanced age. This process is dramatically enhanced by rich environment and intellectual stimulation. It is possible that a 40-minute session with SuperMemo also acts as a good stimulant of these growth and development processes (as much as any challenging intellectual activity)

(Vit Usela, Czech Republic, Nov 2, 1999)
Question:
You advise to merge all SuperMemo collections in one. Does it not contradict the principle of avoiding knowledge interference?
Answer:
No. The same items are not likely to interfere more with each other once they are put in the same collection and repeated one after the other. Indeed, this may even help resolve the interference by means of techniques described in 20 rules of formulating knowledge. For those who learn material related to various branches of knowledge, an interdisciplinary mixture of repetitions often generates unexpected associations that can be a goldmine of ideas in your professional field. This is the simplest illustration of the fact that SuperMemo can make you more creative!

Question:
It is well know that people can be divided into late sleepers, owls, and early sleepers, larks. Has there been any research to indicate what sleeping type has better memory?  
Answer:
The conviction that people are inherently prone to be either larks or owls is wrong. Most owls would claim it is virtually impossible to shift to earlier hours of sleeps while larks just cannot keep their eyes open late in the evening. However, the main reason for this differentiation is not physiology but lifestyle. The stereotype is reinforced by the fact that it is indeed very difficult to shift the sleeping rhythm even by a few hours. If you try to force an owl to start getting up at 5 am, you will expose it to immense mental and physical torture that may quickly result in serious health consequences! However, with the right approach, an owl can gradually be shifted into an early riser mode! The shift must be gradual as no magic force can instantly override the body's internal clock. The main reason why owls are owls is that they tend to excitedly spend their time over a book, movie, or computer game till early hours of the morning. They enjoy the quiet of the night when they can pursue their passion. Subconsciously, they try to get as much of the night time for their pursuits as possible. Were it not for school obligations, family or a job, owls might easily shift to going to sleep at sunrise or later. This is why an owl will find it easy to go to sleep later and later, while it will be nearly impossible to gradually shift the sleeping rhythm in the opposite direction: it is 20-30 minutes earlier each day. For an owl to become a lark, the shift should go in the opposite direction. If an owl goes to sleep 1 hour later each day, soon it will cycle to sleep through the day and finally start getting up as early as 1-2 am. An owl can comfortably stick to such a cycle for quite long until its natural tendency to go to sleep later each day will not ruin it. Moreover, people isolated from external stimuli tend to fall into cycles slightly longer than 24 hours which also explain why it is easier to prolong the day rather than to shorten the night.
The above facts illustrate that there are no underlying physiological reasons for being of a particular sleeping type. The reasons are in the lifestyle and personality (which are both strongly connected). Owls may show lots of excitement for learning as this excitement is the main factor that makes them owls. On the other hand, larks can make better use of early morning hours where they can study in quiet at the time when their brains are most refreshed. The formula for better learning would then probably be to sleep in a way that brings maximum refreshment, i.e. without paying much attention to the actual sleeping hours

(Mariusz Zmuda, Poland, March 22, 2000)
Question:
I sleep seven hours per day and wake up with an alarm clock. I read that using the alarm clock may negatively affect learning. Is it true?
Answer:
There is a significant body of evidence that the you will get the best results in learning if you have your sleep out. Many individuals need eight or more hours of sleep. It is difficult to predict how damaging the alarm clock can be in your case. It will mostly depend on how much sleep your body actually needs

Question: 
Can SuperMemo help remember things that are not stored in SuperMemo?
Answer: 
Yes. To a limited degree. There are three ways in which this is or may be happening: 

1. knowledge which is closely associated with facts and rules you keep in SuperMemo will often be reinforced even if it is not actually stored in the program. For example, if you memorize a few items about John D. Rockefeller without including his photograph and later see his face on TV, it may happen that you will indefinitely be able to recognize his face. You will notice that Rockefeller's face will subconsciously be brought to your imagination at each repetition related to his life 
2. SuperMemo will enhance your mnemonic skills and help you improve your short-term memory. This is the case not only with SuperMemo but also with all other forms of learning 
3. Similarly, learning is likely to have a positive trophic effect on your brain tissue. This should also enhance your general intellectual performance. The scope of this effect is difficult to quantify but it has been proved in a number of experiments that rodents bred in enriched environment grow more neurons, learn faster and live longer

(Ben Lister, Apr 5, 2000)(comment placed at PalmGear in reference to SuperMemo for Palm Pilot)
Comment:
[…] this "scientific study" thing [in reference to SuperMemo], that's a bunch of advertisement junk. It's not science that they use, but simple variable calculations. The program detects the number of times you have gotten something right or wrong and then uses this number to decide when it should next be on a test, like a priority list
Rejoinder:
Ben Lister's observations were surprisingly derived from SuperMemo for Palm Pilot, which reveals little of its internally used optimization procedures (which are slightly simplified as compared with the Windows version). The timing of repetitions may remotely be correlated with the number of bad grades, but is actually derived from the currently estimated so-called memory stability (which reflects how quickly memory traces volatilize) and knowledge difficulty (which reflects the increase in stability as a result of a repetition). Consequently, items with a large number of memory lapses can be repeated in longer intervals than items with fewer memory lapses (unlike it is claimed by Ben Lister). SuperMemo does not use a priority list in scheduling repetitions. The scheduling algorithm does not consider the relationship between items but their reference to time, their difficulty and the history of repetitions. For example, if repetitions were to be delayed, the "priorities" would change. So would the scheduling. The central point of the algorithm is based on plotting the forgetting curve and predicting the optimum timing of the next repetition. The greatest merit of SuperMemo is in fine-tuning the algorithm so that it can adapt to individual skills and knowledge in shortest possible time. No algorithm running in abstraction from the actual forgetting curve stands a chance to compete with SuperMemo in its efficiency (this includes neural algorithms that indirectly will predict the probability of forgetting)

(M.R.W., Poland, March 24, 2000)
Question:
SuperMemo does not seem to provide enough support for those who cannot afford to spend their time daily on regular repetitions. The daily regimen may discourage a large number of potential users. Sometimes one would like to double the effort. On other occasions, one might not feel like working with the program at all. For example, I could never convince my father to use SuperMemo. When he comes back from work, he is often too tired to watch TV, let alone make repetitions. Do you plan to include special tools that would make it possible to learn only on weekends or exclude certain days of the week?
Answer:
Weekly calendar of repetitions is in consideration; however, this option adds complexity without actually providing much learning benefit. It may actually appear harmful:

1. daily repetition regimen comes from the properties of human memory, not from the design of SuperMemo. All delays in making repetitions are unwelcome and should be discouraged
2. we have documented dozens of cases in which users regularly abused Tools : Mercy and ultimately concluded that SuperMemo does not work! Those users blamed SuperMemo, not their own lack of regularity! We have even removed an infamous tool from SuperMemo 7 called Wipe that made it possible to reduce workload by removing the most difficult items. This tool, despite warnings, have ruined the learning process of many users who used it as the shortest way to spending less time on repetitions
3. most of users who prefer SuperMemo for Palm Pilot as opposed to SuperMemo for Windows list its simplicity as an advantage second only to portability. Despite its high satisfaction ratings, the main complaint about SuperMemo for Windows is its complexity and featuritis (i.e. too many features)
4. there is a very simple way towards freeing the user from the daily regimen of repetitions: hiding the statistics. With statistics hidden, the student can delay repetitions without the sense of guilt. He or she can also triple the workload on good days. However, experiments show that in such cases, users add much more learning material that they are able to repeat. This results in significant repetition delays, and a dramatic increase in forgetting. Consequently, the learning process becomes similar to traditional learning, learning results unimpressive and a drop-out rate very high
5. users who are truly unable to spend their time on learning on certain days are encouraged to use Postpone

(Tomasz Strzelczyk, Poland, Jan 31, 2001)
Question:
I would like to invest in a Langmaster course of English. How would you convince me that SuperMemo is superior to the rewise method? 
Answer:
English courses by Dr Lang have a very good reputation for quality and they can be recommended independent of the question on the efficiency of the re-wise method. You could invest in a Langmaster course that best suits your needs and boost your vocabulary with SuperMemo and Advanced English. Alternatively, you could use stand-alone SuperMemo for learning the material from the Langmaster course. As the for re-wise method (developed in Czech Republic around 1994), its principles are similar to SuperMemo; however, we have no doubts as to the superiority of SuperMemo technology that encompasses far more than the repetition scheduling. We have not tested re-wise extensively, but our customers who also use Langmaster CD-ROM titles, unanimously confirm that they prefer to keep their learning material in SuperMemo. Combining Langmaster courses with stand-alone SuperMemo or with Advanced English would probably be the recommended course of action

(Terje A. Tonsberg, Kuwait, Jan 13, 2001)
Question:
I received seemingly wrong results when using Tools : Simulation in SuperMemo. I got the minimum speed of learning for the forgetting index of 8%. Once I reduced the forgetting index to 5% and further to 3%, the expected speed of learning increased substantially!
Answer:
Your observation is accurate. Indeed, there is a discrepancy between the simulation procedure and SuperMemo Algorithm used in computing the optimum schedule of repetitions. In many texts about SuperMemo you will find that SuperMemo ensures the retention programmed with the forgetting index on the assumption there is no delay in repetitions. This is however imprecise. To prevent clogging up the learning process, Algorithm SM-8 makes an assumption for grades Pass and above (3-5) that the interval must increase by at least one day (i.e. it cannot decrease nor can it stay the same). For low values of the forgetting index and for difficult learning material this assumption actually means a significant departure from the expected retention level. Unfortunately, the simulation procedure does not take this fact into the account, and it does not attempt to correct the forgetting rate which increases as a result of the rigid limitation imposed on the increase in intervals. Consequently, for a low value of the requested forgetting index, the measured forgetting index may be higher than the one assumed for the simulation purposes. This will naturally produce skewed simulation results: repetitions scheduled late by Algorithm SM-8 will still produce high retention as programmed by the forgetting index fed into the simulation input data. For that reason, simulation may be inaccurate for a low forgetting index if your learning material is difficult.
In the future, we hope to make it possible to adjust retention for the departure of Algorithm SM-8 from the optimum repetition schedule, as well as to make it possible to simulate repetitions at intervals that fully comply with the forgetting index. That latter option would naturally slow down the learning process even further

(Lisa Arcella, Women's World magazine, Jan 26, 2001)
Question:
What techniques can you use to remember someone's name after you meet them? For example, some sort of word-association; if the person's name is Smith, associating a blacksmith with them might help. If you could give me two or three tips for our readers that would be really helpful
Answer:
Associating Smith with blacksmith and providing a mental image of Smith hammering his colleagues at work is likely to leave a strong memory imprint (the more gruesome or shocking the association, the better it works). The solutions range from low-tech and less efficient to high-tech and "memory-leak-proof": 

• mnemonic techniques - this is how the problem of forgetting used to be solved for centuries 
• spaced repetition - this is the method that eliminates forgetting in the most efficient way (with efficiency limited only by inherent properties of human memory)

Mnemonic techniques: The Smith-blacksmith approach falls into the category of mnemonic techniques, which use the power of the visual cortex of the brain to represent memories that humans are poor at remembering (e.g. complex numbers). We easily remember images and can often recognize faces after very long intervals without repetition in the meantime. However, an intelligent person will often find it difficult to recall seven consecutive digits presented one after another. Humans are inherently poor at numbers! With mnemonic training, the same person may quickly arrive at remembering sequences of 50 digits, cards, or objects. The Guinness Record drives this to unimaginable heights (thousands of digits or playing cards) -- far surpassing what we need in our daily lives. One of the most useful techniques, for remembering numbers (e.g. phone numbers) is the so-called peg list. If you memorize 100 so-called pegs that associate numbers with pictures (e.g. one is tree, two is a switch, three is a tripod, etc.), you will quickly learn to "see" numbers as "scenes". For example, 911 might be a cat ("cat has nine lives") stretched between two trees (assuming tree is one). Memorizing 100 pegs is a substantial effort and not many will want to undertake it. However, remembering a 10-digit number can then be reduced to remembering a 5-event sequence (e.g. my grandmother is chasing the postman who hides in a manhole and is eaten by a giant rat). Such memories tend to be manifold easier to retain. If you need to remember more than 30 numbers, the investment in memorizing the peg list will pay back. Beyond 50 (e.g. your personal phone book), peg-list is a pure saving.

Spaced repetition: The above mnemonic approach converts "difficult memories" to "easy memories" and is a subject of many books and self-improvement tapes worldwide. However, there is a substantial flaw. "Easier memories" are also subject to forgetting! They tend to be lost at a slower pace but they do get lost in the end. Forgetting also affects the peg-list if it is not rehearsed often enough. In other words, we cannot remember without a review/repetition. Spaced repetition can rationalize and simplify the review of study material, and ensure nearly perfect recall. This may not be as easy to present to your readers as the Smith-blacksmith association, however. The major drawbacks of spaced repetition are:

• for a quality application, you need a computer and software called SuperMemo (from Super Memory); also available as freeware
• for top-quality use of SuperMemo (call it "power SuperMemo"), a number of skills are needed, which are considered "complex" by non-technical people (see: Devouring knowledge)

Memory "overflow" is not "fatal"
(Chris Houser, Japan, Sun, Feb 06, 2000 12:13)
Question:
One some website related to SuperMemo I found that without forgetting "the brain would fill up ... with ... fatal results". This sounds quite silly. Does research support this?
Answer:
No. This statement is unfortunate. We are unable to control all what is being written about SuperMemo. The corrected statement might be: Forgetting is needed to clean up room for new memories in the limited space of the human brain. For example, neocortical representations cannot be reconstructed by the hippocampus due to the limited size of its network; hence the constant flow of memories. The reports of patient confusion in cases of reduced forgetting are sporadic and difficult to verify. Genetically engineered mice that exhibit reduced forgetting rate have actually been shown to outsmart normal mice in tasks such as navigating a maze

(Jason Roos, USA, Mar 27, 2001)
Question:
When I need to memorize a bunch information, I make flashcards. My gut is usually a good indicator of when I need to go through them again. It's surprising to me there seems to be so much scientific study behind SuperMemo. (full text below)
Answer:
If you try SuperMemo for some time, you will notice that it is quite liberating to let the computer do the guessing for you. If you later go into thousands of memorized elements, your "gut" will fail you at some point. After all, it is not easy to guess which of your 100,000 items is closest to being forgotten

Jason Roos: When I need to memorize a bunch information, I make flashcards: 

1. I write a question on one side and an answer on the other
2. I gather all the cards up, and go through them one at a time
3. Those cards I get wrong, I set aside in a "don't know yet" pile. Those I get right, I set aside in a "know it" pile
4. After I've passed through the stack once, I pick up the "don't know yet" pile and repeat this sorting process until they've all been memorized

My gut is usually a good indicator of when I need to go through them again. If I feel confident, I know I'm ready to take the test. Intervals are not that accurately determinable, and 4 days for the first one, in my experience, is waaaay too long [in SuperMemo, the first interval will depend on the user and the learning material]. I need to pass through them every 30 minutes to an hour for at least a day, before they're reasonably secure in my head. Of course, it all depends on the type of material and how many days I slept in class. 
This method [SuperMemo] is hardly unique-- that's how many people study. And the effect is identical to your unnecessarily complex and rather tedious, I think, worksheets and software. It's surprising to me there seems to be so much scientific study behind it. I find it fairly simple and obvious

Internet addiction falls out of this site's focus
(Greg, Saturday, July 21, 2001 8:17 AM)
Question:
I am looking for professional information about IAD. Can you help?
Answer:
IAD falls out of this site's focus. We have found for you a couple of links with some interesting excerpts though:

• http://www.concentric.net/~Astorm/iad.html - Internet Addiction Disorder is the term first proposed by Dr. Ivan Goldberg for pathological, compulsive Internet usage. The criteria for this disorder are based on similar criteria for substance abuse disorders found in the DSM-IV. It is ironic that Dr. Goldberg was not serious about proposing this as an official diagnostic category, yet this term became used extensively. Dr. Goldberg recently revised his suggestion to change the term for this condition to Pathological Computer Use, and changed several of the criteria
• http://psychcentral.com/netaddiction/ - Do some people have problems with spending too much time online? Sure they do. Some people also spend too much time reading, watching television, and working, and ignore family, friendships, and social activities. But do we have TV addiction disorder, book addiction, and work addiction being suggested as legitimate mental disorders in the same category as schizophrenia and depression? I think not. It's the tendency of some mental health professionals and researchers to want to label everything they see as potentially harmful with a new diagnostic category. Unfortunately, this causes more harm than it helps people [...] 
  What some very, very few people who spend time online without any other problems present may suffer from is compulsive over-use. But compulsive behaviors are already covered by existing diagnostic categories and treatment would be similar. It's not the technology (whether it be the Internet, a book, the telephone, or the television) which is important or addicting -- it's the behavior. And behaviors are easily treatable by traditional cognitive-behavior techniques in psychotherapy
• http://www.victoriapoint.com/internetaddiction/articles.htm - Internet addiction articles

(Dawid Calinski, Poland, Apr 6, 2001)
Question:
Why does this site not mention learning in the relaxed state? What is your opinion about alpha waves in learning? Do you recommend products like BrainWave Generator, Hemi-Sync, Holosync or Polish Sita biofeedback?
Answer:
We do realize that the proper cognitive environment is paramount for learning. However, for clarity we use the term concentration instead of an all-inclusive relaxation. It is highly recommended that you maximize your concentration by taking into account the following factors:

• being cut off from all sources of interference in learning (telephone, e-mail, conversation, radio and even your favorite music)
• finding the optimum circadian timing for learning (e.g. early in the morning in free running sleep cycle, late in the evening in DSPS individuals who cannot afford free running sleep, etc.)
• all aspects of mental and cognitive health (e.g. stress avoidance, substance abuse, etc.)

The concept of relaxation is often associated with alpha wave learning which has attracted lots of companies that are more interested in their bottom line than their customers actual success in learning. EEG measurements can be used to generally conclude on the current state of the brain in the same way as you could detect bustling activity in a major city by scanning the surrounding electromagnetic field. The usefulness of alpha wave scanning in learning can be compared to the usefulness of electromagnetic field scanning for social life of a city. You need to focus on the causes rather than on symptoms. Alpha waves appear primarily in the absence of visual processing and other intense mental processes. This is why they cannot dogmatically be considered as a desired learning state. After all, the drowsy alpha state that precedes falling asleep is exactly the worst moment for learning during your day.

In evaluating the "relaxation products" you need to differentiate between the relaxation effect and the actual learning effect. The number of companies producing false claims in this field is astounding. It is very easy to fall for a simple solution to a learning problem (e.g. get 10Hz binaural beat difference and your learning problem will go away for life, and perhaps your sex drive will improve at the same time, you will sleep better and you will look younger). The easy learning solution explains why false claims related to "learning in relaxation" are so hard to extinguish.

At the same time, if you need to cope with stress or insomnia, many products in the field may have a legitimate application. Customers of the Polish Sita system jokingly claim that the company would do better if they marketed their product as a napping system. A worthy application on its own. If you know of relaxation products with legitimate claims and proven results, please let us know. We will gladly write about the subject or provide links from this website

Question:
(1) I want to spend my money on the MegaMemory program delivered on cassette tapes. How would you convince me, that I should rather spend money on buying SuperMemo (2) Is SuperMemo the same as SuperLearning developed by Dr Georgi Lozanov from Bulgaria? (3) Which techniques produce a greater increase in the speed of learning: SuperMemo or the mind maps proposed by Tony Buzan?
Answer:
The mnemonic techniques (Tony Buzan, MegaMemory, MindMan, etc.), Suggestopedia (Dr Lozanov) and SuperMemo can all be considered complementary. All of them have to do with optimization:

• In Dr Lozanov's method the stress is put on optimizing the cognitive environment which produces the best effects in the learning process
• In mnemonic techniques, the representation of knowledge is optimized in order to produce the most durable memory engrams
• In SuperMemo, the optimization concerns the spacing of repetitions

To be a successful student, you have to (1) apply mnemonic techniques while (2) using spaced repetition in a (3) optimum cognitive environment. The important advantage of SuperMemo is that many capable students develop quite good tricks as far as mnemonic techniques are concerned. They can also reasonably master their own psychology and physiology to subject it to the learning effort. However, they have no way of optimizing the spacing of repetitions. Mostly due to the fact that the amount and complexity of computation needed to determine the intervals require the use of a computer and the technology proprietary to SuperMemo World. You should always try to extract the best of the teachings of Tony Buzan and others; however, if you are a capable student, you may start off from learning how to optimize the timing of repetitions. As for now, SuperMemo is the world's best tool developed to assist you in this task

Question:
What is your opinion about Suggestive-Accelerative Learning and Teaching (SALT)?
Answer:
The problem with SALT is that it seems difficult to reproduce good results in learning with the method. The flaw may not necessarily be the method itself but its replicable employment (example). Similarly, it can be shown that learning vocabulary with SuperMemo is relatively easy and can be reproduced by self-taught individuals in nearly all cases. However, more advanced techniques, such as incremental reading, require a great deal of expertise and may, in experimental classroom conditions, produce inconclusive results! SALT may be the most representative implementation of the teachings of Dr Georgi Lozanov who himself had to disavow association with a number of teaching schools that try to pull his name under their own umbrella with tags such as SuperLearning, alpha wave learning, NLP biofeedback, accelerative learning, hypnosis, etc. Quality evaluations are scarce and practical applications may not be straightforward

Question:
Do you recommend books by Tony Buzan?
Answer:
Yes. These books belong to the classics of memory improvement and mental training. They also are very motivational. If learning is important to you, reading at least one of Buzan's collection is a must

(Peter Cool, The Netherlands, Nov 6, 1998)
Question:
Last weekend I started to read and exercise Kevin Trudeau's book Mega Memory. What is your opinion about this?
Answer:
MegaMemory is a good system to exercise your mnemonic skills. It is simple, strongly motivational and shall be useful for most students who want to strengthen their ability to master hard-to-memorize material.
The course, however, carries a couple of popular memory myths. Needlessly Kevin Trudeau begins his program with the claim that memories do not get erased as a result of forgetting and are simply becoming inaccessible. This is not true. The example used in the program refers to our bicycle riding skills. It is noted that people retain biking skills for years without repetition. However, biking falls into the domain of procedural learning (including touch typing, playing instruments, sports, etc.) as opposed to declarative learning (e.g. math, vocabulary, learning faces, etc.). Every minute of biking is equivalent to multiple repetitions in declarative learning and retention and forgetting are governed by slightly different principles. Information theory can be used to quickly prove that the brain is not capable of retaining all information in stores in long-term storage. Hence the need for forgetting. 
Note also that FTC has filed a lawsuit against Kevin Trudeau as a result of his marketing overstatements (the lawsuit was settled). Having said that we still strongly recommend Mega Memory or other mnemonic systems as a system complementary to SuperMemo and based on tried ancient mnemonic techniques. As a bonus, if English is your second language, Mega Memory tapes can additionally serve as a course of colorful English (narrated by Trudeau himself). See also: Mega Memory at SuperMemopedia and MegaMemory controversy

Mega Memory controversy
(Tim Stinnett, Mar 19, 2005, 12:42:27)
Question:
I was reading your FAQ and came across a section regarding Kevin Trudeau and his Mega Memory system. In addition to the criticisms of Trudeau already mentioned, you may want to add that Mr. Trudeau's memory apparently is so bad that he cannot even remember our criminal statutes or agreements he made with the federal government. Kevin Trudeau is a two-time convicted felon who served federal time for credit card fraud. Trudeau also was convicted on state charges involving check fraud and impersonating a physician
Answer:
As we may not be able to provide a thorough review of all products and techniques on the market, you can use SuperMemopedia to initiate review articles and place your opinions there. For example, click the Edit tab on the Mega Memory article and expand it to your best knowledge: http://wiki.supermemo.org/index.php?title=Mega_Memory. As for Mega Memory, this is an indisputably entertaining course of ancient mnemonic techniques. Those who do not want to support shady characters standing behind individual products can always look for equivalent alternatives

(M.Z., Poland, Apr 15, 2001)
Question:
While I make my repetitions, I often have problems with focusing on questions. My brain simply wanders off to other subjects. Do you think this is normal?
Answer:
This is a clear indication that your material is either badly structured or poorly selected. Unfortunately, this situation affects quite a number of users. Repetitions affected by concentration problems are dramatically less efficient. A wild guess is that you might be losing 50-95% of your efficiency. If you formulate your material poorly, you may suffer from recall problems (answers are too complex) or comprehension problems (questions are too wordy). Repetitions immediately become less enjoyable or even painful. This will quickly trigger natural defense mechanism. Your brain will search for more productive mental effort such as pondering over the movie you had seen a day before. Poorly selected material will produce exactly the same result. Optimally, you should only store top-importance material in SuperMemo. This comes from the fact that usually you hardly have time to master top-importance items, let alone anything else. If your material does not meet this criterion, it will seem less relevant and simply boring. If you cram for uninteresting exams, the result will be the same. Poorly selected or structured material is the chief cause of showing little progress with SuperMemo. Problems with attention are a clear indication that you need to review your learning process carefully. Probably you will need to do lots of deleting and reformulating. 
In addition, be sure you get enough sleep, avoid stress (e.g. make repetitions before school or work), do not let anyone disrupt you, turn off the radio and TV, turn off your music (even those pieces you love will compete with your items for your brain power). Please read: SuperMemo Decalog, esp. the section entitled Concentration

The term "staggered learning" may sometimes be used to describe "spaced learning"
(SKlein, Holland, Tuesday, December 05, 2000 7:32 AM)
Question:
What is the difference between staggered learning and learning based on spaced repetition?
Answer:
The term "staggered learning" is not used often. It may refer to intermittent learning or learning based on repetition and review. It is used in reference to the curriculum rather than the method of learning. Probably, its association with spaced repetition comes from the fact that it was used in the context of the Leitner method which is a very old form of spaced repetition

Reading also involves active recall
(Tomasz P. Szynalski , Mon, May 14, 2001 16:39)
Question:
I think your website overestimates the importance of active recall, esp. in learning languages. If I read 20 books (purely passive review), my result will be far from zero. On the contrary, my English skills will shoot up
Answer:
Active recall is needed to guarantee the high retention as defined by the forgetting index (even 99%). Depending on volume, structure, delay, etc. passive review may leave as little as less than a percent of recall. However, reading books for the sake of learning English is not just passive review. Each time you encounter a problematic word, the need for comprehension will automatically trigger an active recognition test in which the stimulus is the word in question and the response is its semantic association. This is active recall

Short-term memory requires no spaced repetition
(Mark G. Patterson, USA, Wednesday, July 18, 2001 6:24 AM)
Question:
The encoding phase of SuperMemo could be dramatically improved by providing a micro-spacing algorithm that presented each new item for recall 3 to 4 times during a 30 minute interval in an expanding pattern. For example, 0, 5, 15, 30 minutes
Answer:
Spaced repetition is valid for long-term processes and its purpose is to minimize the number of presentations and maximize the memory effect by sufficient spacing. However, improved recall within the span of short-term memory can be accomplished only in cases where the initial encoding was incomplete or insufficient. In other words, an important assumption in SuperMemo is that the first exposure should be used to formulate a valid memory engram that will last until the first repetition. Ideally, even the concept of final drill is excessive and serves solely as an insurance against imperfect concentration on the memory task. Sufficiently encoded short-term memories will always be converted to long-term memories and will likely last a few days until the moment of the first repetition

The more time you give to SuperMemo, the closer it will approximate your memory needs
(Luis Gustavo Neves da Silva, Brazil, Thursday, January 04, 2001 4:29 PM)
Question:
If I memorize a collection of 200 items with SuperMemo and make regular repetitions, when will my measured forgetting index be closest to the requested forgetting index: after a day, after a week, after a month or after a year?
Answer:
In conditions of no outside interference, the more time you give to SuperMemo, the better it will approach the requested level of retention. However, if you encounter this knowledge in real life (i.e. outside SuperMemo), the result cannot be predicted. For example, interference early in the interval may have no effect, while interference later in the interval may increase retention in the repetition to come and reduce the retention in the repetition that will follow yet another interval. The outcome will depend on the timing relationship of interference and measurement

Keeping things in memory is important! Memorization allows of employing associational thinking
(T.P.S., Poland, Fri, May 18, 2001 17:05)
Question:
What's the difference between persons A and B: Person A can recall thousands of facts in 5 seconds from memory. Person B can look up those facts in 30 seconds from the net. Clearly, person B is more effective, because he/she hasn't invested 30 minutes every day in appending the facts and then repeating them with SuperMemo
Answer:
Person A can produce instant associations between all those thousands ideas. If the number is 10,000, he or she can produce 10,000 x (10,000-1) instant associations of which many may appear useful (depending on the actual content of memory) Person B can produce only as many associations as his short-term memory can hold while browsing the sources (say 50 x 49 in case he can keep 50 things at once in short-term memory)

Delayed repetitions in SuperMemo
(Malcolm Macgregor, Saturday, September 21, 2002 12:32 AM)
Question:
What causes delayed repetitions?
Answer:
Delayed repetitions are usually caused by a user's failure to go through the allocated portion of the learning material. In massive incremental reading, delayed repetitions may also come by design as a result of material overload. Delayed repetitions will always result in an increased measured forgetting index (more forgetting) but can, paradoxically, save student's time by increasing memory consolidation (the speed of learning might be highest for forgetting index around 20-30%). Using Postpone, the student can choose portions of material that will be protected from delay in massive incremental reading. This way, important material takes more time to learn but shows a better recall rate

Forgetting curve for ill-formulated items is flattened
(anonymous, Wednesday, July 25, 2001 2:54 PM)
Question:
I had a 5-months break in using SuperMemo. I resumed my repetitions and noticed that I still remembered many items. Initially, SuperMemo asked me to repeat difficult items (e.g. enumerations). To my surprise, I remembered many of these items. SuperMemo required a 15 days interval, while I made my repetitions after 150 days and still succeeded. I no longer believe in the optimality of the SuperMemo algorithm. Probably it is 10 times worse than optimal
Answer:
Your results are in full compliance with theoretical expectations. It is no surprise that SuperMemo initially tossed the most difficult items at you, and it is no surprise that you showed remarkable recall on these items. Those items clearly belong to those that have not been formulated in compliance with representation rules (e.g. enumerations are notoriously difficult). If you imagine memories as sets of apples (you can see an apple as a single synapse in the brain), good memories are like small collections of well-polished apples. Bad memories (e.g. enumerations, complex items, ambiguous items, etc.) are like large collections of apples of which few are spoilt. Naturally, spoilt apples rot fast and make recall difficult. After just 15 days, all spoilt apples might have been rotten. During the remaining 150 days, the remaining apples rot very slowly. Hence the typical departure of wrongly formulated items from the shape of the classical forgetting curve. For bad items, the curve is flattened (as an expected superposition of several Ebbinghausian curves). SuperMemo blindly obeys your recall criteria. If it takes 15 days to ensure 98% recall, SuperMemo will take no consideration of the fact that at 150 days you may still show 95% recall. This is why SuperMemo 2000 includes leech management. It makes it easy to identify bad items and use auto-postpone or auto-forget options. Auto-postpone will do exactly what you expect, i.e. delay bad items with little impact on overall retention. Auto-forget will help you rebuild memories from scratch. Occasionally, the newly established memory representation will click and your recall will improve. Naturally, the best method against bad items is the use of appropriate representation (see: 20 rules of formulating knowledge for learning). Interestingly, SuperMemo can never predict the moment of forgetting of a single item. Forgetting is a stochastic process and can only operate on averages. A frequently propagated fallacy about SuperMemo is that it predicts the exact moment of forgetting: this is not true, and this is not possible. What SuperMemo does is a search for intervals at which items of given difficulty are likely to show a given probability of forgetting (e.g. 5%). If you look for a numerical measure of the algorithm's inaccuracy, instead of comparing intervals you should rather compare retention levels as the retention is the optimization criterion here. Even for a pure negatively exponential forgetting curve, a 10-fold deviation in interval estimation will result in R₂=exp(10*ln(R₁)) difference in retention. This is equivalent to a drop from 98% to 81%. For a flattened forgetting curve typical of badly-formulated items, this drop may be as little as 98%->95%

Multitasking is not recommended in learning (#6918)
(dansujp, Sun, Sep 16, 2001 3:07 PM)
Question:
Here is another improvement for SuperMemo. When I reviewed the flashcards, I would lay them out on a large table so that I could see 30 at a time, and would pick up the cards for which I knew the answer. Sometimes the answer takes a few seconds to surface. In the mean time I can be looking at other cards and thinking about them in a multitasking fashion. In SuperMemo there is only one question at a time, so it is frustrating to sit there and wait and not have anything else to do until the answer appears
Answer:
Research shows that multitasking considerably reduces cognitive powers. Optimally you should be able to focus on a single recall at a time. In addition, recall should, ideally, be instantaneous. Long and frustrating retrieval times would typically indicate ill-formulated items of high complexity. Your solution might increase the fun of learning for overly complex material, but if you apply the minimum information principle along with other pivotal rules of knowledge representation, multitasking would reduce your processing speed . In the past, we have added a number of options to SuperMemo by sheer user pressure; however, it can be demonstrated that in many cases this have actually done harm to user learning process. We consequently remove options that are frequently misused (e.g. Batch Repetitions, Background Repetitions, some rescheduling tools, and more)

Music and incremental reading
(Mohammed Asad Khan, Pakistan, Thursday, May 02, 2002 1:01 AM)
Question:
Can I read articles in SuperMemo with the help of my favorite music?
Answer:
Optimally, you should have your favorite music turned off when learning. However much it invigorates your brain, it will ALWAYS decrease your focus and take away some mental processing power. Invariably, background music reduces the efficiency of working with SuperMemo. If your learning is boring, you must diagnose the reasons. Most often, user knowledge is not properly formulated for active recall. Incremental reading may require a few months of practice to develop good learning habits. You cannot resolve the "boredom" of learning with background entertainment. Learning must be entertaining on its own!

Memorizing collections such as 20x20 Multiplication Table increases mnemonic computational skills
(Mark, Sun, Jul 29, 2001 2:48)
Question:
Once a user memorizes 20x20 Multiplication Table, will he or she be able to count properly without a calculator or pencil and paper?
Answer:
Yes. It is hardly possible to memorize 20x20 multiplication table without doing some simple calculations in memory. Cramming the results is neither recommended nor is it easy. The calculations made at recall stage actually enhance one's ability to run computations in memory, and decrease the need for a calculator!

Trust SuperMemo to save time
(Mike C, Thursday, September 20, 2001 2:46 AM)
Question:
I have a problem with Mercy. On 9/10 I answered an item, which was then scheduled again on 9/13. Then on 9/17 I ran Mercy. That item ended up getting re-scheduled to 9/19, today. What I'm seeing is that SuperMemo has assigned it an interval of 9 days rather than 3 days. The problem is that if I answer this item Good or Bright it is going to get scheduled out to something like 13 or 15 days, when it really should be only 4 or 5 days
Answer:
Once you get a good grade after a longer interval, SuperMemo will naturally use longer intervals as it will upgrade your recall chances. Your anxiety is understandable. However, by shortening intervals you would actually increase time needed for learning. What is worse, artificial shortening of intervals increases the chances of forgetting due to spacing effect

Memorizing instances of abstract cases is not a waste of time
(SuperMemo R&D, Wed, Aug 01, 2001 21:47)
Question:
In SuperMemo you propose to introduce several examples of the same rule. For example, 13*10=130, 24*10=240 and 69*10=690. One could get dozens of different possible appearances of one principle. Does this make sense?
Answer:
Yes. This is instance training. Problems you solve are instances of a certain abstraction. A single rule-based item requires a very smart mind to produce a strongly applicable abstraction. Several instance items help you make use of the natural properties of neural networks to enforce the abstraction. In many cases, you will achieve better results by memorizing a rule and several instances of its application than by just the rule alone. In SuperMemo, the cost of such a redundancy is negligible. Remember that in SuperMemo you spend most of your time on repetitions of difficult material. Redundancy improves retention by optimizing representation. Paradoxically, by adding redundant instance items, you can often reduce overall workload. And even if the workload were to increase, the applicability of thus-strengthen abstraction is a highly welcome side effect

Poor memory is usually a self-imposed limitation
(darran a., Australia, Mon, Aug 27, 2001 10:47 PM)
Question:
I was tested some years back for my memory, I always had problems learning at school, they told me I had a genetic short term memory loss, possibly inherited from my father, my children show some of the same signs that I have
Answer:
Please consult another specialist! Genetic factors affecting short-term memory are quite unlikely. In addition, it is the long-term memory that makes you succeed in life, while short-term memory can be honed easily with mnemonic training. Hopefully, SuperMemo should help you figure out that your abilities are not much different from others, and that your future rests in your hands (and your brain). Dozens of people claim they have poor memory only to find out, in measurement, that they do not differ much from others (except perhaps for some trainable mnemonic skills). Among those above forty, the claims of poor memory are epidemic

Vacation may feel like "improving memory"
(p.b., Thu, Apr 11, 2002 18:02)
Question:
When I came back from vacation, where I did not do my daily SuperMemo, some 1,500 items awaited me. I found out with surprise that I recall the items better after this 10-day break then on usual days with daily repetitions. Maybe my mind had so good rest that it worked noticeably better?
Answer:
If the vacation took away some stressload or gave you a chance to catch up with sleep, your fresher mind might partly explain a higher recall rate. However, you should also be aware of the placebo effect enhanced by the surprise that you remember so much. If your forgetting is usually 10%, you might have expected 30% after the vacation (as most people do expect). When you had noticed or sensed it is 12% (the more likely value), you could have felt as if it was 8%. It would "feel" as if your scores improved even though they were worse in proportion to the length of the delay

There is no remedy to interference
(Justin, Wed, Nov 07, 2001 23:58)
Question:
What should I do when I get two successive elements that are identical but flipped (i.e. the question goes in the place of the answer)? The first card obviously "refreshes" my memory -- so the "testing" of the second item is inaccurate. I usually just click Fail ('D'), which I is bad for the learning process
Answer:
Your only remedy is introspection and an honest attempt to estimate how you would have scored had the refreshing item not been presented. Otherwise, scoring Bad or Fail should not do much damage to the learning process. In the long run (i.e. when intervals increase) and with a high volume of the learning material, this is usually not a problem to worry about. Successive occurrence of similar items is rare in such circumstances

Spacing effect results from reduced potential for increasing synaptic strength
(Mark G. Patterson, Tuesday, September 25, 2001 3:25 AM)
Question:
Why is the term Spacing Effect used with negative connotations at supermemo.com? Spacing Effect refers to the beneficial effects of spaced repetition (which I prefer to call spaced recall since active recall, not mere repetition or review, is key)
Answer:
Forgetting and the spacing effect are beneficial from the evolutionary point of view as these both evolved to prevent memory overload. However, in the context of learning, both phenomena need to be struggled against by the student. Spacing effect may be interpreted as "shorter intervals - harder learning" or as "longer intervals - easier learning". In other words this might be a glass half-empty case. However, once we understand the molecular origins of the spacing effect, we quickly come to see it as a mechanism directed against remembering. In the same way, once we try to fill a glass with water, we will call it half-full in the middle of the way. Spaced repetition is effective exactly because it goes around the spacing effect, i.e. around the reduced ability to reinforce memories at high levels of retrievability

It is possible to roughly estimate the amount of time needed for learning a portion of material
(Patrik Nilsson, Tuesday, December 18, 2001 11:53 AM)
Question:
Can Tools : Statistics : Simulation help me figure out the date when it is expected that I manage my learning material?
Answer:
Once you introduce an item into the learning process and execute all outstanding repetitions, it is SuperMemo's responsibility to ensure the desired level of retention. For that reason, you can assume that you "managed" your material as soon as it has been introduced into the learning process. Consequently, you do not need to run Simulation. If you want to memorize 1000 items and you decide to introduce 10 items per day into the learning process, you will "manage" the material in 1000/10=100 days. Now you can use Simulation to try to estimate how much work this will require. A rule of thumb is that you need 10x more effort for repetitions than for learning new material. This could indicate that if you memorize 10 items per day, you may expect 100 repetitions per day (at least in the initial period). This number may vary greatly depending on the difficulty of the material and your learning skills and techniques. Use Simulation to get a better estimate. With rescheduling tools (e.g. Postpone), you can also reduce the daily load of repetitions; however, you will then suffer some loss in retention. Another rule of thumb is that to increase your forgetting index from 10% to 20% you would need to either (1) massively overload the learning process (e.g. by increasing the inflow of material 10-fold), or (2) dramatically cut down on the learning effort (e.g. by 90%). For more see: Theoretical aspects of SuperMemo

Use Simulation to estimate workload
(Piotr Wasik, Poland, Tue, Apr 24, 2001 14:26)
Question:
I would like to know how to estimate my workload on a large collection if I commit 40 items per day and keep the forgetting index at the default ten percent
Answer:
If you use Tools : Statistics : Simulation and set: (1) the forgetting index to 10%, and (2) daily repetitions to 230 items, you will get 40 new items memorized per day. In other words, your workload might roughly be 230 items/day (this will vary greatly depending on the quality of your learning material)

Tony Buzan and SuperMemo
(JON DOWAT, Tuesday, February 12, 2002 5:10 AM)
Question:
Is SuperMemo based on the memory research by Tony Buzan?
Answer:
Not directly. However, both SuperMemo World and Tony Buzan try to produce a synthesis of what is know about efficient learning. Those philosophies are largely identical. Our advice related to mnemonic techniques, although not part of SuperMemo itself, is largely based on Buzan thinking. Similarly, Buzan is a proponent of repetition spacing. His proposed increased interval scheme is slightly different from what comes out from computations made by SuperMemo, but is equally valid in practical, non-computer, applications. Tony Buzan has accomplished a great deal promoting "learning to learn" attitudes worldwide. His work fertilized the ground for seeding SuperMemo

Flatter forgetting curve does not increase optimum interval
(Tomasz P. Szynalski, Saturday, August 04, 2001 5:53 AM)
Question:
If the forgetting curve is flatter for difficult items, I will remember them for a longer time, right? Does that suggest that ill-formulated items are remembered better?
Answer:
No. Flattened forgetting curve will increase retention measurements in intervals that are a multiple of the optimum interval as compared with the typical negatively exponential curve for well-structured material. However, the optimum intervals for ill-formulated items will expectedly be shorter as can be observed on the first interval graph in Tools : Statistics : Analysis : Graphs : First Interval. The smoothness of this graph depends on the number of repetitions recorded. In the picture below, over 90,000 repetitions have been recorded

I don't buy memory overload hypothesis in Alzheimer's
(Mike, Tue, May 28, 2002 5:01)
Question:
I'm sure the basic premise of the "memory overload hypothesis" is flawed. The effect of SuperMemo is really no different, at the basic biochemical level, than any other repetitive learning activity (although certainly more efficient). If I dial my mother's phone number 100 times over the next few years, does that also contribute to Alzheimer's?
Answer:
It is important to differentiate between recalling/reusing old memories, and forming new memories. When you redial the same phone number, you are not likely to form new long-term memories. Nor does the overall storage change when you make repetitions of outstand