Ask a room of medical students to name the cranial nerves in order, and many will start mouthing a sentence before they say a single nerve. The sentence carries them through all twelve. Ask what the seventh nerve does, and the sentence has nothing to offer.
Mnemonics, from acronyms and rhymes to stories and imagined routes, are built for exactly that job. They give you a route back to an item without building any understanding of it.
How a Mnemonic Works
Bellezza (1981) described mnemonics as cue structures that a learner builds, then uses to prompt recall. Recall becomes two steps: you rebuild the cue (the sentence), and the cue hands you the item (the nerve).
Some devices hang items on outside pegs, such as the letters of an acronym or places along a familiar route (the method of loci). Others form a chain, as in a story where each item cues the next. A third kind recodes a hard item into an easier one. To remember that Spanish perro means dog, you might picture a dog eating a pear. That is the keyword method, which comes up again below.
He also proposed what a good cue needs. You must be able to regenerate it at recall, tell it apart from other cues, link it easily to its item, and decode it back to the original word. He offered them only as a first step toward theory. Even so, they make sense of some common failures. Pegs that are too alike blur together, and an image you cannot decode later gives you nothing back.
Mnemonics are often explained as pairing words with pictures. Bellezza warned that research had sometimes treated them as if they were all imagery, yet acronyms and rhymes are built from words. Even for the keyword method, Dunlosky et al. (2013) treat the picture account as one side of an unsettled debate.
What the Evidence Shows
Studies of first-letter devices disagree. Some found them better than control procedures, and others did not (Bellezza, 1981). One explanation is that “ROY G. BIV” helps you put the colors in order once you have remembered them, and does little to help you remember them in the first place (Nelson & Archer, 1972, and Morris, 1978, as cited in Bellezza, 1981).
Dunlosky et al. (2013) reviewed the keyword method and reported benefits across many materials and ages, even on near-transfer tasks such as using new words correctly in fresh sentences. They still gave it a low utility rating, because it suits mainly concrete words and its benefit may not last. Earlier studies tested the same students twice, which favors whoever does better the first time. In a study of separate groups, students tested right away remembered more with keywords than with rote repetition, but students tested only after a week showed no advantage. When extra practice equated the groups’ immediate scores, the rote group did better a week later (Wang et al., 1992, as cited in Dunlosky et al., 2013).
Evidence on stories points both ways. An unpublished master’s thesis by Akhter, first author of an anatomy review that summarizes it without methods, found that acronyms, acrostics and rhymes helped students memorize anatomy while storytelling did not beat a control group (Akhter, 2018, as cited in Akhter et al., 2021). Another study found a story matched an acronym immediately and beat it at one week (Rust & Blick, 1972, as cited in Akhter et al., 2021).
The one randomized trial here with medical students is the hardest to read. In a preprint with 79 first-year students, those who watched an audiovisual story outscored those who read highlighted text, slightly at first. By four weeks the text group’s scores had fallen by about two-fifths; the video group’s barely moved (Abdalla et al., 2020). But the groups differed in medium, amount of exposure and narrative at once. Both also took the same test four times, and the group ahead on the first test may have gained more from each retest. So the trial cannot isolate the mnemonic.
Where Mnemonics Stop
Bellezza (1981) put the limit plainly. Mnemonics “operate by the use of cognitive structures that, somewhat disturbingly, have little or no relation to the conceptual content of the material being learned” (p. 247). Learners can even miss structure that is there: Luria’s famous mnemonist memorized 4, 8, 12, 16, 20 without noticing that it climbs by fours (Luria, 1968, as cited in Bellezza, 1981).
Hattie and Donoghue (2016) place mnemonics among strategies for acquiring surface knowledge, the early phase of learning. My reading of that evidence, not a tested finding, is that mnemonics mainly serve retention of discrete items. Apart from narrow near transfer, like using a new word in a sentence, they do little to build the understanding that lets you apply those items to a new problem.
Using Them Well
Save mnemonics for arbitrary material, such as the order of the cranial nerves or side effects that do not follow from a drug’s mechanism. If the material has a structure, learn the structure. Learn the items first, too. An acronym helps you order and retrieve things you already know, and it cannot teach you what the letters stand for (Bakken & Simpson, 2011, as cited in Akhter et al., 2021).
Self-made cues usually beat supplied ones, as long as the learner can make them (Bellezza, 1981). A day later, check each cue against his criteria. Can you rebuild it? Does it decode to one answer only? With use, the cue seems to drop out as direct links form (Bellezza, 1981), so you are not reciting the sentence forever. Then hand the fact over to practice testing and spaced review.
For people who teach, a supplied mnemonic is a reasonable gift for a truly arbitrary list. Where the content has a logic, teach the logic first and let the mnemonic order what is left.
What This Looked Like for Me
I leaned on mnemonics heavily. Anatomy and pharmacology are full of lists with no logic to them, and a good acronym or a vivid image made those lists stick when rereading would not.
What I learned slowly was where they ran out. I could recite a drug’s side-effect profile through a mnemonic and still freeze on a question that described a patient and asked which drug to choose. Answering it meant connecting the mechanism to the patient, which is the work of elaboration and self-explanation. The mnemonic had anchored the facts, and the reasoning had to be built some other way.
I changed many things about how I studied over the same period, so I cannot isolate what any one technique contributed. What I kept was the habit of not mistaking a full list for understanding.
The Core Lesson
A mnemonic builds a cue that leads back to a fact while ignoring what the fact means. It can give encoding a head start, but the evidence on how long that lasts is mixed, so pair it with retrieval and spacing. Build understanding where there is something to understand, and use mnemonics for the facts that have no logic to learn.
The next post turns to contextual learning: what the place you study in does, and does not do, for what you recall later.
This post is part of a series on the science of learning. Each post covers one evidence-based principle and how to apply it to your own studying. Follow us on Instagram @acemeded to keep up with future blog posts and related content.
References
Abdalla, M. M. I., Azzani, M., Rajendren, R., Hong, T. K., Balachandran, Y., Hassan, T. R. F. M., Wei, T. Y., Yahaya, U. K., En, L. J., Ajaykumar, S., Moore, R. A. R., & Haja, M. H. S. (2020). Effect of story-based audio visual mnemonics in comparison with text reading method on memory consolidation among medical students: A randomized controlled trial [Preprint]. Research Square. https://doi.org/10.21203/rs.3.rs-24300/v1
Akhter, N., Nawshin, N., & Khatun, M. (2021). Mnemonic techniques: Characteristics, educational suitability and research prospects in the field of anatomy. Mymensingh Medical Journal, 30(4), 1187–1191.
Bellezza, F. S. (1981). Mnemonic devices: Classification, characteristics, and criteria. Review of Educational Research, 51(2), 247–275. https://doi.org/10.3102/00346543051002247
Dunlosky, J., Rawson, K. A., Marsh, E. J., Nathan, M. J., & Willingham, D. T. (2013). Improving students’ learning with effective learning techniques: Promising directions from cognitive and educational psychology. Psychological Science in the Public Interest, 14(1), 4–58. https://doi.org/10.1177/1529100612453266
Hattie, J. A. C., & Donoghue, G. M. (2016). Learning strategies: A synthesis and conceptual model. npj Science of Learning, 1, Article 16013. https://doi.org/10.1038/npjscilearn.2016.13
