Due to association — No recall without a cue — Memory is due to brain-plasticity — Native retentiveness — Number of associations may practically be its equivalent — Retentiveness is a fixed property of the individual — Memory versus memories — Scientific system as help to memory — Technical memories — Cramming — Elementary memory unimprovable — Utility of verbal memorizing — Measurements of immediate memory — They throw little light — Passion is the important factor in human efficiency — Eye-memory, ear-memory, etc. — The rate of forgetting, Ebbinghaus’s results — Influence of the unreproducible — To remember, one must think and connect.

We are following a somewhat arbitrary order. Since each and every faculty we possess is either in whole or in part a resultant of the play of our associations, it would have been as natural, after treating of association, to treat of memory as to treat of interest and attention next. But, since we did take the latter operations first, we must take memory now without farther delay; for the phenomena of memory are among the simplest and most immediate consequences of the fact that our mind is essentially an associating machine. There is no more preeminent example for exhibiting the fertility of the laws of association as principles of psychological analysis. Memory, moreover, is so important a faculty in the schoolroom that you are probably waiting with some eagerness to know what psychology has to say about it for your help.

In old times, if you asked a person to explain why he came to be remembering at that moment some particular incident in his previous life, the only reply he could make was that his soul is endowed with a faculty called memory; that it is the inalienable function of this faculty to recollect; and that, therefore, he necessarily at that moment must have a cognition of that portion of the past. This explanation by a ‘faculty’ is one thing which explanation by association has superseded altogether. If, by saying we have a faculty of memory, you mean nothing more than the fact that we can remember, nothing more than an abstract name for our power inwardly to recall the past, there is no harm done: we do have the faculty; for we unquestionably have such a power. But if, by faculty, you mean a principle of explanation of our general power to recall, your psychology is empty. The associationist psychology, on the other hand, gives an explanation of each particular fact of recollection; and, in so doing, it also gives an explanation of the general faculty. The ‘faculty’ of memory is thus no real or ultimate explanation; for it is itself explained as a result of the association of ideas.

Nothing is easier than to show you just what I mean by this. Suppose I am silent for a moment, and then say in commanding accents: “Remember! Recollect!” Does your faculty of memory obey the order, and reproduce any definite image from your past? Certainly not. It stands staring into vacancy, and asking, “What kind of a thing do you wish me to remember?” It needs in short, a cue. But, if I say, remember the date of your birth, or remember what you had for breakfast, or remember the succession of notes in the musical scale; then your faculty of memory immediately produces the required result: the ’cue’ determines its vast set of potentialities toward a particular point. And if you now look to see how this happens, you immediately perceive that the cue is something contiguously associated with the thing recalled. The words, ‘date of my birth,’ have an ingrained association with a particular number, month, and year; the words, ‘breakfast this morning,’ cut off all other lines of recall except those which lead to coffee and bacon and eggs; the words, ‘musical scale,’ are inveterate mental neighbors of do, ré, mi, fa, sol, la, etc. The laws of association govern, in fact, all the trains of our thinking which are not interrupted by sensations breaking on us from without. Whatever appears in the mind must be introduced; and, when introduced, it is as the associate of something already there. This is as true of what you are recollecting as it is of everything else you think of.

Reflection will show you that there are peculiarities in your memory which would be quite whimsical and unaccountable if we were forced to regard them as the product of a purely spiritual faculty. Were memory such a faculty, granted to us solely for its practical use, we ought to remember easiest whatever we most needed to remember; and frequency of repetition, recency, and the like, would play no part in the matter. That we should best remember frequent things and recent things, and forget things that are ancient or were experienced only once, could only be regarded as an incomprehensible anomaly on such a view. But if we remember because of our associations, and if these are (as the physiological psychologists believe) due to our organized brain-paths, we easily see how the law of recency and repetition should prevail. Paths frequently and recently ploughed are those that lie most open, those which may be expected most easily to lead to results. The laws of our memory, as we find them, therefore are incidents of our associational constitution; and, when we are emancipated from the flesh, it is conceivable that they may no longer continue to obtain.

We may assume, then, that recollection is a resultant of our associative processes, these themselves in the last analysis being most probably due to the workings of our brain.

Descending more particularly into the faculty of memory, we have to distinguish between its potential aspect as a magazine or storehouse and its actual aspect as recollection now of a particular event. Our memory contains all sorts of items which we do not now recall, but which we may recall, provided a sufficient cue be offered. Both the general retention and the special recall are explained by association. An educated memory depends on an organized system of associations; and its goodness depends on two of their peculiarities: first, on the persistency of the associations; and, second, on their number.

Let us consider each of these points in turn.

First, the persistency of the associations. This gives what may be called the quality of native retentiveness to the individual. If, as I think we are forced to, we consider the brain to be the organic condition by which the vestiges of our experience are associated with each other, we may suppose that some brains are ‘wax to receive and marble to retain.’ The slightest impressions made on them abide. Names, dates, prices, anecdotes, quotations, are indelibly retained, their several elements fixedly cohering together, so that the individual soon becomes a walking cyclop?dia of information. All this may occur with no philosophic tendency in the mind, no impulse to weave the materials acquired into anything like a logical system. In the books of anecdotes, and, more recently, in the psychology-books, we find recorded instances of monstrosities, as we may call them, of this desultory memory; and they are often otherwise very stupid men. It is, of course, by no means incompatible with a philosophic mind; for mental characteristics have infinite capacities for permutation. And, when both memory and philosophy combine together in one person, then indeed we have the highest sort of intellectual efficiency. Your Walter Scotts, your Leibnitzes, your Gladstones, and your Goethes, all your folio copies of mankind, belong to this type. Efficiency on a colossal scale would indeed seem to require it. For, although your philosophic or systematic mind without good desultory memory may know how to work out results and recollect where in the books to find them, the time lost in the searching process handicaps the thinker, and gives to the more ready type of individual the economical advantage.

The extreme of the contrasted type, the type with associations of small persistency, is found in those who have almost no desultory memory at all. If they are also deficient in logical and systematizing power, we call them simply feeble intellects; and no more need to be said about them here. Their brain-matter, we may imagine, is like a fluid jelly, in which impressions may be easily made, but are soon closed over again, so that the brain reverts to its original indifferent state.

But it may occur here, just as in other gelatinous substances, that an impression will vibrate throughout the brain, and send waves into other parts of it. In cases of this sort, although the immediate impression may fade out quickly, it does modify the cerebral mass; for the paths it makes there may remain, and become so many avenues through which the impression may be reproduced if they ever get excited again. And its liability to reproduction will depend of course upon the variety of these paths and upon the frequency with which they are used. Each path is in fact an associated process, the number of these associates becoming thus to a great degree a substitute for the independent tenacity of the original impression. As I have elsewhere written: Each of the associates is a hook to which it hangs, a means to fish it up when sunk below the surface. Together they form a network of attachments by which it is woven into the entire tissue of our thought. The ‘secret of a good memory’ is thus the secret of forming diverse and multiple associations with every fact we care to retain. But this forming of associations with a fact — what is it but thinking about the fact as much as possible? Briefly, then, of two men with the same outward experiences, the one who thinks over his experiences most, and weaves them into the most systematic relations with each other, will be the one with the best memory.

But, if our ability to recollect a thing be so largely a matter of its associations with other things which thus becomes its cues, an important p?dagogic consequence follows. There can be no improvement of the general or elementary faculty of memory: there can only be improvement of our memory for special systems of associated things; and this latter improvement is due to the way in which the things in question are woven into association with each other in the mind. Intricately or profoundly woven, they are held: disconnected, they tend to drop out just in proportion as the native brain retentiveness is poor. And no amount of training, drilling, repeating, and reciting employed upon the matter of one system of objects, the history-system, for example, will in the least improve either the facility or the durability with which objects belonging to a wholly disparate system — the system of facts of chemistry, for instance — tend to be retained. That system must be separately worked into the mind by itself — a chemical fact which is thought about in connection with the other chemical facts, tending then to stay, but otherwise easily dropping out.

We have, then, not so much a faculty of memory as many faculties of memory. We have as many as we have systems of objects habitually thought of in connection with each other. A given object is held in the memory by the associates it has acquired within its own system exclusively. Learning the facts of another system will in no wise help it to stay in the mind, for the simple reason that it has no ‘cues’ within that other system.

We see examples of this on every hand. Most men have a good memory for facts connected with their own pursuits. A college athlete, who remains a dunce at his books, may amaze you by his knowledge of the ‘records’ at various feats and games, and prove himself a walking dictionary of sporting statistics. The reason is that he is constantly going over these things in his mind, and comparing and making series of them. They form for him, not so many odd facts, but a concept-system, so they stick. So the merchant remembers prices, the politician other politicians’ speeches and votes, with a copiousness which astonishes outsiders, but which the amount of thinking they bestow on these subjects easily explains.

The great memory for facts which a Darwin or a Spencer reveal in their books is not incompatible with the possession on their part of a mind with only a middling degree of physiological retentiveness. Let a man early in life set himself the task of verifying such a theory as that of evolution, and facts will soon cluster and cling to him like grapes to their stem. Their relations to the theory will hold them fast; and, the more of these the mind is able to discern, the greater the erudition will become. Meanwhile the theorist may have little, if any, desultory memory. Unutilizable facts may be unnoted by him, and forgotten as soon as heard. An ignorance almost as encyclopedic as his erudition may coexist with the latter, and hide, as it were, within the interstices of its web. Those of you who have had much to do with scholars and savants will readily think of examples of the class of mind I mean.

The best possible sort of system into which to weave an object, mentally, is a rational system, or what is called a ‘science.’ Place the thing in its pigeon-hole in a classificatory series; explain it logically by its causes, and deduce from it its necessary effects; find out of what natural law it is an instance — and you then know it in the best of all possible ways. A ‘science’ is thus the greatest of labor-saving contrivances. It relieves the memory of an immense number of details, replacing, as it does, merely contiguous associations by the logical ones of identity, similarity, or analogy. If you know a ‘law,’ you may discharge your memory of masses of particular instances, for the law will reproduce them for you whenever you require them. The law of refraction, for example: If you know that, you can with a pencil and a bit of paper immediately discern how a convex lens, a concave lens, or a prism, must severally alter the appearance of an object. But, if you don’t know the general law, you must charge your memory separately with each of the three kinds of effect.

A ‘philosophic’ system, in which all things found their rational explanation and were connected together as causes and effects, would be the perfect mnemonic system, in which the greatest economy of means would bring about the greatest richness of results. So that, if we have poor desultory memories, we can save ourselves by cultivating the philosophic turn of mind.

There are many artificial systems of mnemonics, some public, some sold as secrets. They are all so many devices for training us into certain methodical and stereotyped ways of thinking about the facts we seek to retain. Even were I competent, I could not here go into these systems in any detail. But a single example, from a popular system, will show what I mean. I take the number-alphabet, the great mnemonic device for recollecting numbers and dates. In this system each digit is represented by a consonant, thus: 1 is t or d; 2, n; 3, m; 4, r; 5, l; 6, sh, j, ch, or g; 7, c, k, g, or qu; 8, f or v; 9, b or p; 0, s, c, or z. Suppose, now, you wish to remember the velocity of sound, 1,142 feet a second: t, t, r, n, are the letters you must use. They make the consonants of tight run, and it would be a ‘tight run’ for you to keep up such a speed. So 1649, the date of the execution of Charles I., may be remembered by the word sharp, which recalls the headsman’s axe.

Apart from the extreme difficulty of finding words that are appropriate in this exercise, it is clearly an excessively poor, trivial, and silly way of ‘thinking’ about dates; and the way of the historian is much better. He has a lot of landmark-dates already in his mind. He knows the historic concatenation of events, and can usually place an event at its right date in the chronology-table, by thinking of it in a rational way, referring it to its antecedents, tracing its concomitants and consequences, and thus ciphering out its date by connecting it with theirs. The artificial memory-systems, recommending, as they do, such irrational methods of thinking, are only to be recommended for the first landmarks in a system, or for such purely detached facts as enjoy no rational connection with the rest of our ideas. Thus the student of physics may remember the order of the spectral colours by the word vibgyor which their initial letters make. The student of anatomy may remember the position of the Mitral valve on the Left side of the heart by thinking that L.M. stands also for ‘long meter’ in the hymn-books.

You now see why ‘cramming’ must be so poor a mode of study. Cramming seeks to stamp things in by intense application immediately before the ordeal. But a thing thus learned can form but few associations. On the other hand, the same thing recurring on different days, in different contexts, read, recited on, referred to again and again, related to other things and reviewed, gets well wrought into the mental structure. This is the reason why you should enforce on your pupils habits of continuous application. There is no moral turpitude in cramming. It would be the best, because the most ec............