Memory

Sleep's role in memory

Sleep is vital for long term memory encoding, consolidation, but less so for the retrieval. However not all sleep stages are equally as important. SWS is mostly responsible for both encoding and consolidation of declarative memories1, while REM sleep seems to be required for the consolidation of declarative memories, that are of emotional significance1,2, as well as spatial memory3. NREM2 was found to correleate with consolidation of motor sequence memory4, though SWS also affects motor coordination5.

Memory and sleep deprivation

After total sleep loss, encoding and consolidation of memory are dose-dependent impaired1. The deficit cannot be decreased after caffeine consumption1. Nevertheless this does not seem to be the case with more common partial or chronic sleep loss, where four hours of SWS-rich sleep, achieved by increased homeostatic sleep pressure6, doesnot influence encoding, consolidation and retrieval of declarative memories1. In addition retrieval is not meaningfully impaired by sleep loss1.

However REM sleep could be more important for those who use mnemonic techniques to ease the encoding of factual information via vibrant imagery and memory palaces, since they incoperate REM sleep dependent memories as mentioned previously.

Introduction

Mnemonics are powerful memory techniques that can improve memorization1. For students, using memory techniques for studtheirded can help drastically reduce the total time spent studying and score higher on exams2. Therefore, mnemonics, along with the Method of Loci, are viable alternatives for teenagers and students who are willing to trade some sleeping hours for studying hours by utilizing polyphasic sleep to learn more efficiently. The following mnemonics methods are not only usable on their own, but can also be combined with the Method of Loci or Spaced Repetition Systems for even greater benefits.

Different types of mnemonics

Mnemonics are memory tools that aid in memorization3. Every mnemonic device is based on association. The associations make it easier for humans to recall complex information4. Later these associations can be further associated with easier memorable mental images, rhymes, songs, stories and/or locations. There are various types of mnemonics that can be applied for each learner, so choose a method that works best personally.

Memorizing Numbers:

Memorizing numbers can be a challenging task without the use of any memory techniques. A mnemonic tool that students should use for memorizing numbers is called the Major System.

With the Major System, the first thing to do is trais word will aid in memorizing the number. Splitting the number and building two words nsform numbers from 0-9 into consonant sounds5. Then, add vowels to form a word. This also possible if it is a preferred choice. All learners need to do beforehand is to memorize the corresponding consonant for each number. Learners can assign a number a consonant sound or use the most common Major system as demonstrated below.

Major system

Numbers	consonant sounds
1	s, z
2	n
3	m
4	r
5	l
6	sh, ch, … (same sound)
7	k, g
8	f, ph
9	b, p

Example: A learner wants to memorize when Buckminster Fuller invented the Dymaxion Schedule (1943).

It is important to establish a link to Buckminster Fuller with 1943 and create an easily memorable image that will aid in the memorization process. In step 1, convert both things into something visible. If Buckminster Fuller’s physical appearance has been memorized, converting him into something more memorable is not necessary. Now, convert 1943 into a word, using the Major System. Possible words are: table-rem. In this example, imagine Buckminster Fuller taking a nap on his table or dreaming about something on a table. Visualize the image for about ten seconds. Alternatively, associating Buckminster Fuller with Ted Mosby is also a possible option, as both of them are architects, and use him as an image in the mind. Once familiar with this system, learners can memorize numbers without having any issues.

Alphabet Peg System

Alphabet Peg Systems enables learners to memorize up to 26 pieces of information. They make use of the fact that everyone can recall the alphabet, which is a given route. Before learners are able to use the alphabet for better memorization, each letter first has to be associated with something. This can either be a list of animals or a list of jobs with their first initial.

Example:

A- ant

B- beaver

C- crocodile

D- dolphin

E- elephant

…

After the list is completed, it is possible to use it for every type of information, even shopping lists, as often as one likes. To achieve this, learners have to let their mnemonic peg interact with the new information and then visualize the outcome.

Person-Action-Object (PAO) System

The PAO System is an advanced system for memorizing numbers6. With this system, it is easier to remember larger numbers, but learners need to invest more time beforehand. It evolves naturally from a simpler number to letter system like the Major System or the Dominic System. It is largely known and used by memory athletes7. With this system, learners create mental images by associating two digit numbers with one person, one action and one object. The image is created by visualizing the person for the first two digits, then the action for the next two digits, then the object for the last two digits for the mental image. This system allows memorization of six digit numbers with only one mental. If it is a number with more than six digits, like pi, it is possible to store the mental images on a loci-route/ in a memory palace.

How to create the first PAO-System:

As mentioned previously, the PAO-System is created by aligning two digit numbers (00-99) with one person, action and object each. First, memorize an easier number to letter system. This will enable every number (00-99) to be translated into initials. The next step is to find people or characters from movies that have these initials. Afterwards, associate an action and an object with each initial/ person.

Example: Number 21 is transformed into a Person-Action-Object System, and has already been memorized by the major system. The initials for 21 are  “n” for the first digit, “t” or “d” for the second digit. A possible person could be Nikola Tesla. Now, start associating that person with an action and an object.

3. Memorizing Vocabulary

Linking Method

Memorizing vocabulary is typically done by creating a mental image that contains the new word itssel and the meaning of the word8. Then, it is necessary to imagine the mental image for about 10 seconds before moving on. The new word is usually visualized as an already known word that sounds similar to the new one or by association. The word’s new meaning is usually easier to visualize and should not require any associations before being implemented in the image.

Example: Schlafen (to sleep):

“It's not so easy to form an association with this word. A key image is of two

city-types standing over a man who has fallen asleep. One of them is laughing

loudly, the other is saying, 'sssshhhhh, you'll wake him'. 'Sssshhh' and

'laughing' are roughly equivalent to Schlafen.”

This method may seem very complicated, but it is highly effective and easier than one would expect. Once the basics are clear. It is important to remind oneself that both the meaning and the new word have to be parts of the mental image. Fortunately, some authors have established how it works and written dictionaries that already contain these mental images. For an even better outcome, automate the learning process by combining this method with a spaced repetition system like Anki or Supermemo.

Spaced repetition

Spaced repetition systems are flashcard-based systems that make use of the forgetting curve and space the repetition intervals right before learners would forget something. The intervals enlarge after each successful repetition and are spaced accordingly to the review of the recall as either “again”, “good” or “easy” most of the time. The algorithms behind these systems are highly complex. The best known type of algorithm is the SuperMemo algorithm, which has been shown to increase the average examination points of students9 (Both Anki and the newest version of Supermemo use different types of the SuperMemo algorithm) .

How the SuperMemo algorithm works is explained below (and why Anki and Supermemo are superior to Quizlet etc.). It is important to note that simpler programs do not have a review system and rely mostly on the Leitner-System:

Figure 1. Leitner System

The problem with this system is obvious: it shows the flashcards too often, does not space each flashcard individually, yet relies on a fixed system. Thus, it does not differentiate between hard-to-remember and easy-to-remember flashcards. Nor does this system space the intervals at the latest possible time, before learners would forget it. All in all, this makes the system highly inefficient, though it was a good alternative for the standard rote learning in the non-digital age. Supermemo-Algorithms make use of a review system, that lets the algorithm learn how difficult it is to remember each flashcard:

Figure 2. Supermemo Algorithms

Moreover, the modern SuperMemo-Algorithms individuate between graduated and new flashcards.

SuperMemo-Algorithms are superior to rote learning and fixed repetition systems, because they not only make use of the forgetting curve but also allow the algorithms to space reviews right before learners would forget learned materials, which results in a reduced amount of repetitions. This effectively reduces the total time spent studying and makes use of the spacing-effect10. However, they also account for how difficult it is to remember each factum and place the repetitions accordingly. Additionally, there are many different SuperMemo-Algorithms. The spaced repetition software Anki is based on the SM-2 Algorithm, while the Version of the SuperMemo defines what SM-Algorithm is used.

Benefits of using mnemonics

There are numerous benefits of mnemonics, the most obvious and important of which is to drastically reduce the total time spent on studying with proper use7. In addition, it is apparently more fun than mindless rote learning; it has the potential to enliven even boring topics. Using mnemonics and better studying techniques also often leads to much less frustration and anxiety11; as a result, it creates more exciting ways to learn - learners also don't often experience failures as much as in common rote learning, since the information is likely to stick for years with good mnemonics and only few repetitions. In addition, learners who make use of Mnemonics have been shown to perform better on exams11. The reduction of the total time spent studying can also reduce the urge of young polyphasic sleepers to attempt sleep reducing schedules. In addition, applying mnemonics on a daily basis can enrich social life - there are mnemonic types that assist in the memorization of names and faces, and remembering important appointments also becomes easier with the use of mnemonics.

The best of both worlds: Utilizing mnemonics in combination with spaced repetition systems

Since Spaced Repetition Systems and mnemonics have both been shown to be an effective learning method2,9, it is wise for learners to make use of both. The Mnemonics can help learners get the information into long term memory right away, while the Spaced Repetition Systems make sure the information is not forgotten, and can still aid in transferring the facts into long term memory, if the mnemonics alone are not enough. The combination of both mnemonics and Spaced Repetition is nothing new, so the SuperMemo website advocates for using mental imagery and mnemonics12.

The easiest way to implement this combination is to either create Mnemonics while transfering the data learners want to memorize into a spaced repetition system. In addition, if students are fans of batching, start with creating mnemonics for every factum, transferring everything into a Spaced Repetition System and start rewinding. The viable ways to implement this into a daily routine together with polyphasic sleeping are listed in the following section.

Potential applications in polyphasic sleeping

Owing to the importance of sleep in memory consolidation13, undisturbed studying and refreshing breaks, polyphasic sleepers have advantages over monophasic sleepers in terms of studying. There are different ways polyphasic sleepers can utilize multiple concepts to optimize their study sessions.

Scheduling study sessions before naps:

All polyphasic schedules contain both REM and NREM2 after the adaptation process. Especially REM has been shown to be responsible for elaborative encoding13, which is the type of memory encoding that is utilized when mnemonics is used3. Furthermore, this idea can be optimized by placing the study session in a night wake period, which facilitates focusing and studying without interruptions. However, the studying period can also be scheduled before a daytime nap.

Figure 3. Mnemonics on Segmented sleep

The second core sleep of Segmented schedule contains abundant REM sleep, which is a powerful tool to boost elaborative encoding capacity. Alternatively, students could also divide the study sessions into two different segments, one of which is reserved for creating mnemonics and the other is for rehearsal, as shown in the example below.

Figure 4. Mnemonics on Siesta sleep

The second Siesta core contains both SWS and REM sleep, which further helps with elaborative encoding13. Getting both these vital sleep stages also helps with memory consolidation, declarative and procedural memory functions. Additionally, scheduling this study method can be improved even further, when learners can utilize the Pomodoro Technique. The first 2-3 Pomodoro cycles can be used to create mnemonics for the study material and the last 1-2 Pomodoro cycles can be used to recite learned materials.

Figure 5. Mnemonics and Pomodoro on E1-extended

Using the last Pomodoro cycle for recitation and placing it right before the nap will assist the encodement process of the episodic memory13, especially if done right before a REM nap placed at early hours in the day.

Lastly, students can also combine mnemonics, spaced repetition, the Pomodoro technique and polyphasic sleeping effectively. Creating mnemonics and converting them into flashcards can be done during the Pomodoro cycles while the 20-minute default break can be traded for some sleep and the daily review can be scheduled before a nap. This automates the rehearsal procedure and ensures that learners can keep the information for the long term by perfectly spacing the repetition intervals for each flashcard.

Figure 6. Mnemonics and Pomodoro on DC1

The daily review period is scheduled right before the REM-heavy core sleep on DC1, which boosts the ability to remember procedures by repetition8. Alternatively, if EEG readings show that the nap contains some amount of REM sleep, preparing for another set of mnemonics around that time is also recommended.

Conclusion

Mnemonics are strong memory tools that strengthen memorization - they can reduce the total time spent studying and help students perform better at exams. These memory techniques have the potential to be used even more effectively when learners combine them with other productivity boosters (e.g, the Pomodoro Technique) to make use of the elaborative encoding during REM sleep13, but also with the method of loci. Once trained to use mnemonic techniques effectively, learners can further understand their applications, develop their knowledge about them, proceed with more difficult learning tools (e.g, the method of loci) and finally start building a reliable studying routine. Tho mnemonics have not been shown to help in the memorization of random lists of words11. Spaced repetition system can also optimize studying and be used as a last resort, if learners are unable to find enough mnemonics in time. However, very few polyphasic sleepers combine mnemonics effectively with their sleep, which leads to room for speculation whether the timed study session brings along noticeable effects. All in all, this blog serves to detail the memory systems that polyphasic sleepers can try out for their learning experience if there is any interest in utilizing these learning tactics.

References

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3. Memory Improvement Techniques – Start Here:  – Boosting Your Powers of Recall With Mnemonics, Senses and Emotions.” Mindtools.Com, 2009, www.mindtools.com/memory.html. Accessed 26 Apr. 2020.
4. Kaschel, R., Sala, S. D., Cantagallo, A., Fahlböck, A., Laaksonen, R., & Kazen, M. (2002). Imagery mnemonics for the rehabilitation of memory: A randomised group controlled trial. Neuropsychological Rehabilitation, 12(2), 127–153.
5. “Major System - Memory Techniques Wiki.” Artofmemory.Com, artofmemory.com/wiki/Major_System. Accessed 24 June 2020.
6. “Person-Action-Object (PAO) System - Memory Techniques Wiki.” Artofmemory.Com, artofmemory.com/wiki/Person-Action-Object_(PAO)_System. Accessed 24 June 2020.
7. “Person-Action-Object (PAO) System - Memory Techniques Wiki.” Artofmemory.Com, artofmemory.com/wiki/Person-Action-Object_(PAO)_System#List_of_mnemonists_who_use_a_PAO_system. Accessed 24 June 2020.
8. “How to Memorize Vocabulary - Memory Techniques Wiki.” Artofmemory.Com, artofmemory.com/wiki/How_to_Memorize_Vocabulary. Accessed 24 June 2020.
9. Teninbaum, Gabriel H. "Spaced repetition: A method for learning more law in less time." J. High Tech. L. 17 (2016): 273.
10. Dempster, F. N. (1989). Spacing effects and their implications for theory and practice. Educational Psychology Review, 1(4), 309–330. doi:10.1007/bf01320097.
11. Mocko, M., Lesser, L. M., Wagler, A. E., & Francis, W. S. (2017). Assessing Effectiveness of Mnemonics for Tertiary Students in a Hybrid Introductory Statistics Course. Journal of Statistics Education, 25(1), 2–11. doi:10.1080/10691898.2017.1294879.
12. “SuperMemo.Com.” Www.Supermemo.Com, www.supermemo.com/de/archives1990-2015/articles/20rules. Accessed 24 June 2020.
13. Cheng, S., & Werning, M. Composition and replay of mnemonic sequences: The contributions of REM and slow-wave sleep to episodic memory. Behavioral and Brain Sciences. 2013;36(6):610–611. doi:10.1017/s0140525x13001234. [PMC]
14. Ullrich Wagner, A., et al. "Signs of REM sleep dependent enhancement of implicit face memory: a repetition priming study." (2002). [PMC]