A mnemonic (pronounced [nəˈmɑnɪk] in American English, [nəˈmɒnɪk] in British English) is a memory aid. Mnemonics are often verbal, are sometimes in verse form, and are often used to remember lists. Mnemonics rely not only on repetition to remember facts, but also on associations between easy-to-remember constructs and lists of data, based on the principle that the human mind much more easily remembers data attached to spatial, personal or otherwise meaningful information than that occurring in meaningless sequences.
The word mnemonic shares etymology with Mnemosyne, the name of the titan who personified Memory in Greek mythology. The first known reference to mnemonics is the method of loci described in Cicero's De Oratore.
Examples of simple mnemonics
One common mnemonic device for remembering lists consists of an easily remembered word, phrase, or rhyme whose initials or other characteristics are associated with the list items. The idea lends itself well to memorizing hard-to-break passwords as well.
Science and technology
- Stellar classification uses a peculiar group of letters, easily remembered using the phrase, "Oh Be A Fine Girl, Kiss Me." With two new categories L and T for brown dwarfs, the revised version to "Oh Be A Fine Girl/Guy, Kiss My Lips Tenderly." (Sometimes "Right Now Smack Wow." was added at the end, although these classes are not part of the sequence and are no longer current.)
- For naming the planets in order from the Sun, the phrases:
- "My Very Easy Memory Jingle Seems Useful Naming Planets"
- "Mary's Violet Eyes Made John Stay Up Nights Proposing"
- "Man Very Early Made Jars Stand Up Nearly Perfect"
- "My Very Eager Mother Just Served Us Nine Pizzas"
- "Mexican Vultures Enjoy Making Jam Sandwiches Using New Plums"
- "Many Visitors Eat Meat, Just Simple Under-Nourished People"
- "My Very, Educated Mother Just Showed Us Nine Planets"
- "Many Vikings Enjoyed Making Jelly Sometimes Using Norse Plums"
- "My Very Easy Method Just Speeds Up Naming Planets"
- "Many Vast Elephants Munch Jam Sandwiches Until [they] Nearly Pop"
- "Many Very Early Men Just Sat Under Neath Pluto"
- "Mom Visits Every Monday, Just Stays Until Noon, Period"
Biology, Medicine & Anatomy
Medical mnemonics are quite common, see .
- An example of a visual mnemonic for the drug "hydralazine" could be represented as "lazy hydra" that is on strike holding a sign "NO more work". "NO" in the above case symbolizes Nitrous Oxide, which is related to the drug's mechanism of action. For examples of this technique, see .
- A well-known mnemonic used to remember the 12 cranial nerves uses no profanity but isn't politically correct: "Oh Oh Oh, To Touch And Feel A Girl, Very Sexy And Hot".
- Note: The cursive "S" stands for "spinal". The accessory nerve splits in a spinal and cranial branch. The latter quickly combines with the vagus nerve, whereas the spinal branch continues on its own - hence the "S" as a reminder.
- The clean version is making ground though, and it goes like this: "On Old Olympus' Tiny Top A Finn And German Viewed Some Hops", or "On Old Olympus' Towering Top A Finely Vested German Viewed A Hawk" (with variations; some say "terraced tops", "towering top(s)" or "topmost top", and "viewed some hops" is sometimes rendered as "vaulted a hedge").
- The letters stand for Olfactory, Optic, Occulomotor, Trochlear, Trigeminal, Abducent, Facial, Auditory, Glossopharyngeal, Vagus, Accessory, and Hypoglossal.
- A profane example is "Some Anatomists Like Fucking, Others Prefer S & M" for the external carotid artery branches.
- Some ways of remembering biological groupings in taxonomy:
- "Kings Play Cards On Fat Green Stools"
- "Kings Play Chess On Fine Grained Sand"
- "Kings Play Chess Often For Great Sport"
- "Kings Play Chess On Funny Green Squares"
- (in the less politically correct category) "Kings Play Chess On Flat Girls' Stomachs".
- "Kids Prefer Cheese Over Fried Green Spinach".
- One more that begins with "kids" is "Kids Playing Chase On Freeway Get Squashed" (sounding rather like a public service announcement).
- "King Phillip Came Over For Good Spaghetti".
- "King Phillip Came Over From Germany, Swimming" is popular in America, as is "King Phillip Could Only Find Green Socks".
- "King Penguins Copulate Often For Greater Satisfaction" also works, as does Kevin Please Come Over For Gay Sex, as was popularized on the program TV Funhouse.
- "Some Girls Fill Out Clothes Pretty Keenly"
- Many biology students use the tune of "Row row row your boat" to assist in remembering the characteristics of DNA:
We love DNA,
Made of nucleotides,
A phosphate, sugar and a base,
Bonded down one side.
Adenine and Thymine,
Make a lovely pair,
Guanine without Cytosine,
Would be rather bare.
- Chemistry students use the phrase "LEO says GER" to keep the two halves of a redox process straight, since the Loss of Electrons is Oxidation while the Gain of Electrons is Reduction. Another version is the word "OIL-RIG", meaning Oxidation Is Loss, Reduction Is Gain (of electrons).
- The first few elements of the Periodic Table can be remembered with "Harry He Likes Beer But CanNot Obtain Food".
- A longer version, covering the elements from Helium to Potassium, is "Here Lies Benjamin Bold; Cry Not Old Friend; Needlessly Nature Magnifies All Simple People Sometimes, Clots and Kings." Skipping Calcium, the subsequent elements from Scandium to Zinc (the first group of transition metals) can be remembered via "Scandinavian T V Corrupts Many French Coalmen's Nieces and Cousins (Cu Zins)".
- The universal gas constant "PV/T" was remembered in the 1960's by saying "Pee" "Vee" over the "Telephone". Pee Vee was a television character in the 1960s that was always talking on the telephone.
- The perverse phrase "Gay Garrett Rape Our Young Girls But Violet Gives Willingly" is used to remember the electronic color codes of resistors, capacitors and other electronic components. Occasionally the phrase "for Silver and Gold" is tacked on to the end, referencing the color of the bands which denote tolerance. It is also sometimes seen as "Bad Boys Rape Our Young Girls Behind Victory Garden Walls", or "Burke Bastard Raped Our Young Girl Bloody Virginity Gone West". A milder version is "Bright Boys Rave Over Young Girls But Veto Getting Wed."
- The also somewhat lewd phrase "Bob Eats Carol's Virgin Pussy In A Big Garage Licking Mostly Her Hot Moist Loins In Out In is also used in electronics to remember transistor output types given which input is common.
- "King Xerxes Can Seduce Lovely Princesses" aids in remembering the microwave frequency bands, in order of increasing wavelength.
- "Twinkle, twinkle little star, power equals I squared R."
- A mnemonic to remember which way to turn common (right handed) screws and nuts, including light bulbs is "Righty tighty, lefty loosey".
See also: Trigonometry mnemonics
- Many mnemonics have been devised for remembering the digits of pi, consisting of phrases or verses in which successive digits of pi are obtained by counting the number of letters in each word. (Fortunately, the first thirty digits of pi contain no zeroes). Some are:
- "May I have a number?"(May = 3, I = 1, have = 4, etc. 3.1416)
- "May I have a large container of coffee?" (3.1415926)
- "May I have a large container of orange juice?" (3.14159 265)
- "How I wish I could recollect pi easily today." (3.14159 265)
- "How I want a drink, alcoholic of course, after the heavy lectures involving quantum mechanics!" (3.14159 265358979)
- (Alternate version of previous) "How I need a drink, alcoholic in nature, after the heavy lectures involving quantum mechanics!" (3.14159 265358979)
- See "Poe, E.: Near a Raven" for an extreme example.
- Two mnemonics for the constant e (the base for natural logarithms) are "We require a mnemonic to remember e whenever we scribble math" and "To express e, remember to memorize a sentence to simplify this". The lengths of the words constitute the number 2.7182818284, an approximation of e to 11 decimal places.
- Many people remember the order of operations in arithmetic with the word Brackets Of (fractions: 1/2 of 2) Division Multiplication Addition Subtraction (BODMAS or BOMDAS). In the United States, students often use the sentence Please Excuse My Dear Aunt Sally, where the E signifies exponentiation. Occasionally the phrase is modified to My Dear Mother's Aunt Sally, with the second M standing for modulo; this is more often seen in the context of programming languages, where the modulo operation is more common.
- Many secondary school students remember the basic trigonometric functions with the phrase SOH-CAH-TOA (pronounced "soak a toe-uh").
SOH ... Sine = Opposite leg divided by the Hypotenuse
CAH ... Cosine = Adjacent leg divided by the Hypotenuse
TOA ... Tangent = Opposite leg divided by the Adjacent leg
*A much sportier way to remember it is with the phrase:
- Saddle Our Horses, Canter Away Happily Toward Other Adventures.
- Saddle Our Horses, Canter Away Happily Toward Other Adventures.
Or, as popularized at Cincinnati's, they use the simple phrase Sally Can Tell : Oscar Has A Hard On Always. (It's been theorized that mnemonic devices that reference strong emotions, such as sexual feelings, imprint a stronger memory. However "Hat On" works equally well, but seems to be less memorable.)
Another phrase used in English schools is Six Overweight Heffalumps Came And Heavily Trod On Arthur.
Oscar Had A Heap Of Apples also works if you can remember the sine, cosine, tangent order.
- "One Hopes, And Hopes, On America" was widely taught to British schoolchildren during World War II (the sine-cosine-tangent order was presumed). Not only was it a good mnemonic, it also served to reassure the children that Great Britain was not doomed to Nazi annihilation.
- You can also remember the basic trigonometric functions with the phrase "Some Old Hippie, Caught Another Hippie, Tripping On Acid", or simply, "Old Hippies Are High On Acid
- You can also consider: Some People Have, Curly Black Hair, Through Proper Brushing, Where S=Sine;P=Perpendicular;B=Base;C=Cos;T= Tan (S=P/H;C=B/H;T=P/B)
- Another, very true, trigonometric mnemonic taught to British schoolchildren was "Signs Of Happiness Come After Having Tankards Of Ale".
- Yet another alternative (taught at King Alfred's Grammar School, Wantage, Oxon, England in the 1960s) is:
Over Head Subway (O/H = S)
Algebra Helps Clarity (A/H = C)
Oxford Are Terrific (O/A = T).
- The name Roy G. Biv helps us to remember the order of the colors in the spectrum. In England "Richard Of York Gave Battle In Vain" is popular (Red, Orange, Yellow, Green, Blue, Indigo, Violet). In an alternate version, "Battle" is replaced with "Birth".
- A mnemonic used by physics students to remember the Maxwell relations in thermodynamics is "Good Physicists Have Studied Under Very Fine Teachers", which helps them remember the order of the variables in the square, in clockwise direction. Another mnemonic used here is "Valid Facts and Theoretical Understanding Generate Solutions to Hard Problems", which gives the letter in the normal left to right writing direction.
- The Group XVIII inert gases (helium, neon, argon, krypton, xenon and radon) may be recalled by the sentence "Heaven Never Arsked Kriegspiel's eXtra Rent"
- The phrase "We guarantee certainty, clearly referring to this light mnemonic." represents the speed of light in meters per second through the number of letters in each word: 299792458.
- "DOC" represents phases of the Moon by shape: "D" is the waxing moon; "O" the full moon; and "C" the waning moon. In the Southern hemisphere, this is reversed, and the mnemonic is "COD". A French mnemonic is that the waxing moon at its first "premier" quarter phase looks like a 'p', and the waning moon at its last "dernier" quarter looks like a 'd'. In German, the Moon is compared to a handwritten small letter a for "Abnehmen" (waning) and a z for "Zunehmen" (waxing). One more (Northern hemisphere) mnemonic, which works for most Romance languages, says that the Moon is a liar: it spells "C", as in crescere (Italian for "to grow") when it wanes, and "D" as in decrescere ("decrease") when it waxes.
- "Red, right, return" used to remember which sea mark denotes which side of a sailing channel.
- On the other hand, "there´s always some red port (wine) left" is also used to remember the basics in sea faring.
- Let's not forget the word that reminds us that the best plan is usually a simple plan: K-I-S-S (Keep it Simple, Stupid!)
- Many young Australian, Kiwi and British children remember the compass points in order in clockwise with the phrase Never Eat Soggy Weet-bix, or Never Eat Shredded Wheat (North, East, South, West). Weet-bix and Shredded Wheat are popular breakfast cereals in Australia, New Zealand and Britain. Another variation is Never Ever Smoke Weed. In the United States, school children are often taught with the phrase Never Eat Soggy Waffles or Never Eat Sour Worms.
- The acronym HOMES is also a mnemonic aid that can be used to remember the names of the North American Great Lakes (Huron, Ontario, Michigan, Erie, Superior). SMHOE is also useful to remember their positions from North to South, "Super Man Helps Every One" to remember their positions from West to East, and if you like, "Sam's Horse Must Eat Oats" helps one to remember their ordering by size from largest to smallest. (See if you can find others!)
- The Dutch Antilles can be remembered by thinking of the Leeward Islands as the ABC islands and of the Windward Islands as the SSS islands.
- The nations of Central America can be remembered (in order north to south) by "Better Go Home Every Night Completely Paid".(Belize, Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica, Panama)
- To help me remember whether you lose time or gain it, I made this little mnemonic: EWG and WEL. East to West Gains and West to East Loses
- Beginning music students trying to memorize the notes of the staff use the mnemonics "Every Good Boy Does Fine", or alternatively, "Empty Garbage Before Dad Freaks" (or, in Britain, "Every Good Boy Deserves Favour" - also the title of a play with music by Tom Stoppard and Andre Previn), and "FACE" for the lines and spaces of the Treble Clef respectively. The Bass Clef equivalents are "Good Boys Do Fine Always" or "Good Boys Deserve Fine Apples" or "Great Big Dogs Fight A lot" for lines, and "All Cows Eat Grass" or "All Cars Eat Gas" for spaces.
- The strings on a six-string guitar with standard tuning can be remembered using the mnemonic "Elephants And Donkeys Grow Big Ears".
- A mnemonic for remembering the number of days in the months of the year, practically a cultural universal in the United States, is "Thirty days hath September/April, June and November." (Although this is only part of a longer rhyme, this is the only part that most people remember, so they commonly complete it with words similar to "... except February alone, and that has twenty-eight days clear, and twenty-nine in each leap year." The full mnemonic is "Thirty days hath September/April, June and November/All the rest have thirty-one/except February alone/which has eight and a score/until leap year gives it one day more.")
- Another mnemonic for the days of the months is not a rhyme or a jingle, but a gestalt. Whereas the traditional mnemonic simply associates the name of the month with the number of days, this one emphasizes the sequence. The 31 and less-than-31-day months would be easy to remember if they simply alternated, but the pattern of month lengths is not that simple. They alternate until the fourth 31-day month, July, which is immediately followed by another 31-day month. Since the human hand has four fingers, one can, given an appropriate mind-set, perceive this pattern in a view of the knuckles of two fists, held together. The raised knuckles can be seen as the 31-day months, the dips between them as the 30-day-months-and-February, and the gap between the hands ignored. (Thus: left-hand-pinky-knuckle = January, dip = February, left-hand-ring-knuckle = March, dip = April, and so on to left-hand-index-knuckle = July; then continue with right-hand-index-knuckle = August, dip = September, etc).
Many tournament Scrabble players employ anamonics, a form of initialization mnemonic, for the purposes of learning and quickly recalling sets of acceptable words. An anamonic consists of a "stem" (usually of six or seven letters), paired with a semantically related phrase, in which each letter of the phrase can be added to the stem and rearranged to form at least one acceptable word. For example, if a player has the tiles ACDEIRT on her rack, and recalls the anamonic "DICE-ART = casino math diploma", she will know precisely which letters may be played through to form 8-letter words, and will hopefully be aided in finding the words: ACCREDIT, RADICATE, ACRIDEST, RATICIDE, DICENTRA, CERATOID, TIMECARD, CITRATED/TETRACID/TETRADIC, TRACHEID, READDICT, PICRATED, and ARTICLED/LACERTID.
A mnemonic technique is one of many memory aids that is used to create associations among facts that make it easier to remember these facts. Popular mnemonic techniques include mind mapping and peg lists. These techniques make use of the power of the visual cortex to simplify the complexity of memories. Thus simpler memories can be stored more efficiently. For example, a number can be remembered as a picture. This makes it easier to retrieve it from memory. Mnemonic techniques should be used in conjunction with active recall to actually be beneficial. For example, it is not enough to look at a mind map; one needs to actively reconstruct it in one's memory.
Other methods for remembering arbitrary numbers or number sequences use numerological (lit. number+word) systems such as the abjad, where each numeral is represented by a consonant sound. These systems take advantage of the memory's ability to store more information by organizing it into "chunks".
An example of a widely used system for memorizing numbers as words is the major system.
Number rhyme system
This is an example of a "peg list". It is useful for remembering ordered lists, especially for people with strong auditory learning styles. The following numbered list is static. Note the rhyme of the digit and the word (one/bun, two/glue, and so on). The items you wish to remember should be associated with each word. A similar system utilizing a combination of this and the preceding "abjad" system can easily yield numbers through 100 or higher (ex. 76 lash, 77 lilly)
Egg and spear or number shape system
This is another peg system, much like the number-rhyme system but more suitable for those with visual learning styles (a one looks like a candle; a two looks like a swan, and so on).
- Candle, spear
Visual mnemonics are popular in medicine as well as other fields. In this technique, an image portrays characters or objects whose name sounds like the item that has to be memorized. This object then interacts with other similarly portrayed objects that in turn represent associated information.
Other mnemonic systems
- Method of loci
- Mnemonic verses
- Acronym System
- Link System
- Room System
- Peg System including number-rhyme, number-shape, and number-consonant conversions.
- Major System
- Goroawase System
Arbitrariness of mnemonics
A curious characteristic of many memory systems is that mnemonic devices work despite being (or possibly because of being) illogical, arbitrary, and artistically flawed. "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? Medical students never forget the arbitrary nationalities of the Finn and German. 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; 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 (by relying on some external way to tie each mnemonic to a number).
History of mnemonics
See the method of loci.
- 010 Memorizer (commercial software for memorizing numbers)
- 2Know - Windows Freeware for converting numbers to words using the Major System. Now in English, German, and French.
- Random secure password generator with automatic mnemonic generation
- Free software to help memorise Pi
- AidToMemory.com, mnemonics collection and forum
- Use mnemonics to learn English
- Human Memory
- Homepage of the World Memory Championships
- Mick Curtis memory techniques A practical memory course.
- Google Answers: How to Have a Good Memory
- Memory Joggers Using Mnemonics to teach children Math
- The Memory Page: Tutorials and tips on how to improve your memory.
- Science mnemonics From Science Jokes
- Tools for Improving Your Memory from Mind Tools
- Method of loci about Memory Palaces
- The Effect of the Integrated Keyword Method on Vocabulary Retention and Motivation by Dr. Joern Hauptmann
- Medical Mnemonics.com: World's Database of Medical Mnemonics - "A free online searchable database of medical mnemonics to help students of health-related professions remember the important details."
- Memory Improvement and Learning Information
- Memory Master
- Mind Tools
- World Wide Brain Clubcs:Mnemotechnická pomůcka