A mnemonic ( //, with a silent "m"), or mnemonic device, is any learning technique that aids memory. To improve long term memory, mnemonic systems are used to make memorization easier. A mnemonic system is "special techniques or strategy consciously employed in an attempt to improve memory(Carlson & Heth, 2010)".Commonly encountered mnemonics are often verbal, such as a very short poem or a special word used to help a person remember something, particularly lists, but a mnemonic may instead be visual, kinesthetic or auditory. Mnemonics rely on associations between easy-to-remember constructs which can be related back to the data that are to be remembered. This is based on the observation that the human mind much more easily remembers spatial, personal, surprising, physical, sexual or humorous or otherwise meaningful information, as compared to retrieving arbitrary sequences.
The word mnemonic is derived from the Ancient Greek word μνημονικός mnemonikos ("of memory") and is related to Mnemosyne ("remembrance"), the name of the goddess of memory in Greek mythology. Both of these words refer back to μνημα mnema ("remembrance"). Mnemonics in antiquity were most often considered in the context of what is today known as the Art of Memory.
The major assumption in antiquity was that there are two sorts of memory: the "natural" memory and the "artificial" memory. The former is inborn, and is the one that everyone uses every day. The artificial memory is one that is trained through learning and practicing a variety of mnemonic techniques. The latter can be used to perform feats of memory that are quite extraordinary, impossible for most people to carry out using the natural memory alone.
First letter mnemonics
One common mnemonic for remembering lists consists of an easily remembered acronym, or phrase with an acronym that is associated with the list items. The idea lends itself well to memorizing hard-to-break passwords as well. For example, to remember the colours of the rainbow, use the mnemonic "Richard Of York Gave Battle In Vain" or the fictitious name "Roy G. Biv". Another one is HOMES to help people remember the names of all of the Great Lakes (Huron, Ontario, Michigan, Erie, and Superior.) In electronics, color codes are used on some components, with each color representing a specific value (0-9). Numerous mnemonics exist to help remember the sequence of numbers where the first letter of each word represents the first letter of the name of the color for that number. One such mnemonic is "Bill Brown Realized Only Yesterday Good Boys Value Good Work", representing the colours black (0), brown (1), red(2), orange, yellow, green, blue, violet, gray and white (9). 
Mnemonics for numerical sequences
Mnemonic phrases or poems can be used to encode numeric sequences by various methods, the most common using the number of letters in each word. For example, the first 15 digits of the mathematical constant pi (3.14159265358979) can be encoded as "How I need a drink, alcoholic of course, after the heavy lectures involving quantum mechanics". A large number of so-called piems have been devised, some containing thousands of digits; see the article on "Piphilology" for examples in multiple languages.
Arbitrariness of mnemonics
A curious characteristic of many memory systems is that mnemonics work despite being (or possibly because of being) illogical or arbitrary. "Roy" is a legitimate first name, but there is no actual surname "Biv" and of course the middle initial "G" is arbitrary. Why is "Roy G. Biv" easy to remember in order to memorise the order that the seven colours of the rainbow appear? ROYGBIV can also be expressed as the almost meaningless phrase "Roy Great Britain the Fourth" again referencing "Roy" but using the GB national code for Great Britain and the Roman numerals for 4, viz: IV. The sentence "Richard of York gave battle in vain" is commonly used in the UK. Any two of the three months ending in -ember would fit just as euphoniously as September and November in "Thirty days hath...", yet most people can remember the rhyme correctly for a lifetime after having heard it once, and are never troubled by doubts as to which two of the -ember months have thirty days. A bizarre arbitrary association may stick in the mind better than a logical one.
One reason for the effectiveness of seemingly arbitrary mnemonics is the grouping of information provided by the mnemonic. Just as US phone numbers group 10 digits into three groups, the name "Roy G. Biv" groups seven colors into two short names and an initial. Various studies (most notably The Magical Number Seven, Plus or Minus Two) have shown that the human brain is capable of remembering only a limited number of arbitrary items in working memory; grouping these items into chunks permits the brain to hold more of them in memory.
Programming in machine code, by supplying the computer with the numbers of the operations it must perform, can be quite a burden, because for every operation the corresponding number must be looked up or remembered. Looking up all numbers takes a lot of time, and mis-remembering a number may introduce computer bugs.
Therefore a set of mnemonics was devised. Each number was represented by an alphabetic code. So instead of entering the number corresponding to addition to add two numbers one can enter "add".
Although mnemonics differ between different CPU designs some are common, for instance: "sub" (subtract), "div" (divide), "add" (add) and "mul" (multiply).
This type of mnemonic is different from the ones listed above in that instead of a way to make remembering numbers easier, it is a way to make remembering numbers unnecessary (e.g. by relying on the computer's assembler program to do the lookup work.)
In foreign-language acquisition
Mnemonics can be helpful in learning a foreign language, for example by adapting a hard-to-remember foreign word to a pre-existent phrase in the learner's native language - using folk etymology. Linguist Ghil'ad Zuckermann has proposed many Anglo-Hebraic lexical mnemonics for English-speaking students of Israeli Hebrew. For example, in trying to assist the learner to remember ohel, the Hebrew word for tent, Zuckermann proposes the memorable sentence "Oh hell, there's a raccoon in my tent". The memorable sentence "There's a fork in Ma’s leg" may help the learner remember that the Hebrew word for fork is mazleg, and so forth. The notable linguist Michel Thomas taught students to remember that estar is the Spanish word for to be by using the phrase "to be a star". These are sometimes known as linkwords.
Mnemonics are also useful for learning elements of a foreign language that do not exist in the native language of the learner. For example, in Spanish language acquisition, a student may learn the gender of nouns by associating masculine nouns with the color blue and feminine nouns with red. This allows them to create visual images such as a foot stepping on a pie and blue filling squirting out the sides. The Spanish word for "foot" is el pie, a masculine noun, so recollection of the blue filling will cue recall of the gender of the word.
- Art of memory
- List of mnemonics
- List of visual mnemonics
- Memory sport
- Method of loci
- Mnemonic dominic system
- Mnemonic goroawase system
- Mnemonic link system
- Mnemonic major system
- ^ Catherine Soanes; Angus Stevenson; Sara Hawker, ed (29 March 2006). Concise Oxford English Dictionary (Computer Software) (11th ed.). Oxford University Press. pp. Entry mnemonic.
- ^ Liddell, H. G.; R. Scott (1889). Intermediate Greek-English Lexicon. Oxford: Oxford University Press. ISBN 0-19-910206-6.
- ^ Gambhir, R.S. (1993). Foundations Of Physics. 2. New Age International. p. 49. ISBN 8122405231. http://books.google.com/books?id=r-Qpy0KQayIC&pg=PA49&dq=resistor+code+mnemonic&hl=en&ei=0yNyTpCgLI-3hAe35OnICQ&sa=X&oi=book_result&ct=result&resnum=1&sqi=2&ved=0CDMQ6AEwAA#v=onepage&q=resistor%20code%20mnemonic&f=false.
- ^ Anglo-Hebraic lexical mnemonics for English-speaking students of Israeli Hebrew, by Ghil'ad Zuckermann.
Carlson, N. R., & Heth, C. D. (2010). Psychology, the science of behaviour. (4th ed.). Toronto: Pearson Canada.
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