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The use of mnemonics

Let's look a little deeper into the value of mnemonics for knowledge acquisition. By “knowledge acquisition”, I mean the sort of information you learn from textbooks — information that is not personal, that you need for the long-term.

In this context, I believe the chief value of mnemonic strategies is to help you recall information that needs to be remembered in a particular order. Thus we use mnemonics to help us remember the order of the planets, the order of musical notes on the stave, the order of the colors in a rainbow.

Sometimes we impose an order to make something easier to remember. Thus, HOMES is an established acronym to help people remember the Great Lakes of North America (Huron, Ontario, Michigan, Erie, Superior). The order of the lakes has no meaning, except that, ordered in such a way, the initial letters form a word.

Notice that, of course, the sole assistance this acronym offers is to serve as a reminder cue, by telling you the initial letters of the lakes (and how many there are). You have to already know the names of the lakes.

Other mnemonics for the Great Lakes provide slightly more information, by involving a meaningful order. Thus, “Sam's Horse Must Eat Oats” orders the lakes according to size, and “Sergeant Major Hates Eating Onions” tells you the order of the lakes from west to east.

None of these help you remember the actual names of the lakes.

You could use words similar in sound to the lakes’ names, to help in remembering the names. However, this may well result in a mnemonic that is harder to remember. For example, “Superior Mitch Again sees a Herons’ Eyrie Entire” makes far less sense and is a much harder sentence to remember than “Sergeant Major Hates Eating Onions”.

All this emphasizes the main point about mnemonics, a point that sometimes gets a little lost in the shuffle. Mnemonics are adjuncts to learning. They have their place, and they are extremely effective for their purpose, but you have to remember that their purpose is very limited. Thus, if you wished to learn the Periodic Table of Elements (a question about ways of memorizing the Periodic Table was actually what provoked this article), then you could simply devise a first-letter mnemonic for the table, such as:

He Helps Limping Beggars Borrow Crutches Nicely Or Fairly Near. Naturally Magazines Allow Simple Punctuation Should Clear Arguments. (the first 18 elements, i.e., the first three rows of the Table).

And of course, this won’t help you in any way if you are not already very familiar with the names of the elements. Nor will it tell you anything at all about the significance of the Periodic Table.

Why would you want to memorize the Periodic Table of Elements?

I don’t mean this question to indicate contempt for the task, I actually believe deeply in the value of having core information tamped down, as it were, deep into your knowledge base. You cannot develop any expertise in a subject without knowing the core facts — really knowing, in the same way you know your name and birthdate and, maybe, the names of the players in your favorite sports team, or the words to a favorite song, or the names of the characters in your favorite TV show. (Mnemonics do not, in fact, play a role when you have that depth of knowledge. Once you know something at the level of instant accessibility, you don’t need a mnemonic. But mnemonics can be of great help in the early stages of developing your knowledge.)

But let’s return to the question. Why do I ask it? Because, whenever you want to learn something, you should ask yourself why. Not in the spirit of “does it really matter?”, but with the purpose of establishing precisely your goal. Notice the word “precisely”. It’s not enough to simply say, “Well, I need to know the Periodic Table because I’m studying chemistry, and the teacher tells me I have to know it.” Why does your teacher insist you learn the Periodic Table? How does it help your understanding of chemistry?

The Great Lakes of North America are simply several large bodies of water in geographical proximity. Knowing their names is of no deep significance, has no larger meaning. The Periodic Table, however, does have larger meaning. The order of elements is no arbitrary thing, and the placement of an element in a particular place in the Table is deeply significant.

The Periodic Table arranges the elements in such a way as to demonstrate the pattern underlying the physical and chemical similarities between elements. If you know where an element is in the Table, you know a great deal about the element.

To know that, however, you must understand a great deal more about the Periodic Table than simply the order of the elements. The order of the elements tells you nothing in itself.

So, what is it that you really need to know? Not the order, as such. Not simply: Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminum Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton etc. The Periodic Table is a table for good reason, and you should never lose sight of that.

The rows have significance. The columns have significance. You don’t want to be able to say, “Oh, Scandium. That’s between Calcium and Titanium.” So?

More to the point would be if you knew Scandium was in row 4 and column 3B — that would tell you something (if you knew the significance of the rows and columns).

I’m not knocking the use of mnemonics to learn this sort of information. Mnemonics, used wisely, can facilitate your learning in the beginning. But, if the information you want to memorize has any meaning, you need to combine the use of mnemonic strategies with the use of strategies that are appropriate for meaningful learning. Never forget that the purpose of mnemonic strategies is to help with arbitrary information, facts that have no meaningful connection with each other.

Thus, to master the Periodic Table, you should look at the underlying principles and the meaningful clusters. Use mnemonics to memorize members of meaningful clusters, by all means. Just remember to clearly articulate precisely what you need to know (and then, redefine your goals at intervals as your knowledge grows), and organize the information in ways that support those precise goals. Then apply your mnemonics judiciously.

Visual vs verbal mnemonics

I have also been prompted to discuss another favorite issue - the question of visual imagery vs verbal mnemonic techniques. Here's a quick run-through of the situation as I understand it.

One study that compared verbal and visual imagery methods for remembering serial items (lists of words) found that using a verbal strategy resulted in equal performance on both lists of items rated as "high imagery" and "medium imagery". The two visual imagery techniques (method of loci, and pegword) resulted in higher performance than the verbal strategy for the high-imagery list, but poorer performance for the medium-imagery list. (Marston & Young, 1974).

A more recent study found that connecting three nouns by imagery was more beneficial for immediate unexpected recall than relating them by sentence, however, after a week, recall was the same for both techniques (Hishitani, 1985).

It is well-established that people differ in their abilities to visualize, and clearly the usefulness of visual imagery is partly dependent on whether you are a "high-imager" or a "low-imager" (but don't be fooled by these categorical labels - people will vary along a continuum rather than fall into an either-or category).

This talent also seems to change over the course of one's life. It has been suggested that older adults in particular might be better advised to use verbal mnemonics rather than visual image techniques, as they apparently find it difficult to produce and remember visual images (Poon, Walsh-Sweeney, & Fozard, 1980; Baltes & Kliegl, 1992).

Not entirely independent of these individual differences, there is also a significant difference between the effectiveness of visual images presented to you and those you must generate for yourself.

There is also some evidence that imagery techniques are more effective in particular types of memory tasks compared to others. Herrmann (1987) suggested that interactive imagery was the most effective strategy for paired associate learning (linking two items together), but a story mnemonic was most effective for free recall (remembering various items in any order).

On a related subject, a study that looked into the usefulness of bizarre imagery as a mnemonic aid found that bizarre images were remembered better in the immediate term but not the long term, and only if the images were experienced as part of a mixed list (bizarre and non-bizarre items), and the learner could control their pace of learning (Iaccino & Sowa, 1988). A number of studies have failed to find any particular benefit to constructing bizarre images, and indeed, have suggested that bizarre images take longer to construct and may result in poorer performance. Most recently, the bizarreness advantage in mixed lists was eliminated when alternative retrieval strategies were encouraged (McDaniel, DeLosh & Merritt, 2000). These researchers suggested that the advantage of bizarreness depends on your retrieval strategy (whether or not it is based on distinctiveness).

In sum, then, I would say that use of visual imagery is an entirely personal matter, that there is no clear superiority of visual over verbal techniques, and that (as always) it comes down to individual idiosyncracy. Don't feel pressured into using imagery if you're not easy with it. And if you are comfortable with imagery, still restrict your use of the technique to situations where the images come easily - don't spend more time on constructing images than is warranted; be open to using other techniques. There's no magic to visual imagery. Meaningfulness, organization, depth of processing are the crucial elements in learning, not the precise tools you use to get there.