The Principles of Psychology, by William James

Chapter 16

Memory.

In the last chapter what concerned us was the direct intuition of time. We found it limited to intervals of considerably less than a minute. Beyond its borders extends the immense region of conceived time, past and future, into one direction or another of which we mentally project all the events which we think of as real, and form a systematic order of them by giving to each a date. The relation of conceived to intuited time is just like that of the fictitious space pictured on the flat back-scene of a theatre to the actual space of the stage. The objects painted on the latter (trees, columns, houses in a receding street, etc.) carry back the series of similar objects solidly placed upon the latter, and we think we see things in a continuous perspective, when we really see thus only a few of them and imagine that we see the rest. The chapter which lies before us deals with the way in which we paint the remote past, as it were, upon a canvas in our memory, and yet often imagine that we have direct vision of its depths.

The stream of thought flows on; but most of its segments fall into the bottomless abyss of oblivion. Of some, no memory survives the instant of their passage. Of others, it is confined to a few moments, hours, or days. Others, again, leave vestiges which are indestructible, and by means of which they may be recalled as long as life endures. Can we explain these differences?

Primary Memory.

The first point to be noticed is that for a state of mind to survive in memory it must have endured for a certain length of time. In other words, it must be what I call a substantive state. Prepositional and conjunctival states of mind are not remembered as independent facts -- we cannot recall just how we felt when we said 'how' or 'notwithstanding.' Our consciousness of these transitive states is shut up to their own moment -- hence one difficulty in introspective psychologizing.

Any state of mind which is shut up to its own moment and fails to become an object for succeeding states of mind, is as if it belonged to another stream of thought. Or rather, it belongs only physically, not intellectually, to its own stream, forming a bridge from one segment of it to another, but not being appropriated inwardly by later segments or appearing as part of the empirical self, in the manner explained in Chapter X. All the intellectual value for us of a state of mind depends on our after-memory of it. Only then is it combined in a system and knowingly made to contribute to a result. Only then does it count for us. So that the EFFECTIVE consciousness we have of our states is the after-consciousness; and the more of this there is, the more influence does the original state have, and the more permanent a factor is it of our world. An indelibly-imprinted pain may color a life; but, as Professor Richet says:

"To suffer for only a hundredth of a second is not to suffer at all; and for my part I would readily agree to undergo a pain, however acute and intense it might be, provided it should last only a hundredth of a second, and leave after it neither reverberation nor recall."1

Not that a momentary state of consciousness need be practically resultless. Far from it: such a state, though absolutely unremembered, might at its own moment determine the transition of our thinking in a vital way, and decide our action irrevocably.2 But the idea of it could not afterwards determine transition and action, its content could not be conceived as one of the mind's permanent meanings: that is all I mean by saying that its intellectual value lies in after-memory.

As a rule sensations outlast for some little time the objective stimulus which occasioned them. This phenomenon is the ground of those 'after-images' which are familiar in the physiology of the sense-organs. If we open our eyes instantaneously upon a scene, and then shroud them in complete darkness, it will be as if we saw the scene in ghostly light throught [sic] the dark screen. We can read off details in it which were unnoticed whilst the eyes were open.3

In every sphere of sense, an intermittent stimulus, often enough repeated, produces a continuous sensation. This is because the after-image of the impression just gone by blends with the new impression coming in. The effects of stimuli may thus be superposed upon each other many stages deep, the total result in consciousness being an increase in the feeling's intensity, and in all probability, as we saw in the last chapter, an elementary sense of the lapse of time (see p. 635).

Exner writes:

"Impressions to which we are inattentive leave so brief an image in the memory that it is usually overlooked. When deeply absorbed, we do not hear the clock strike. But our attention may awake after the striking has ceased, and we may then count off the strokes. Such examples are often found in daily life. We can also prove the existence of this primary memory-image, as it may be called, in another person, even when his attention is completely absorbed elsewhere. Ask someone, e.g., to count the lines of a printed page as fast as he can, and whilst this is going on walk a few steps about the room. Then, when the person has done counting, ask him where you stood. He will always reply quite definitely that you have walked. Analogous experiments may be done with vision. This primary memory-image is, whether attention have been turned to the impression or not, an extremely lively one, but is subjectively quite distinct from every sort of after-image or hallucination. . . . It vanishes, if not caught by attention, in the course of a few seconds. Even when the original impression is attended to, the liveliness of its image in memory fades fast."4

The physical condition in the nerve-tissue of this primary memory is called by Richet 'elementary memory.'5 I much prefer to reserve the word memory for the conscious phenomenon. What happens in the nerve-tissue is but an example of that plasticity or of semi-inertness, yielding to change, but not yielding instantly or wholly, and never quite recovering the original form, which, in Chapter V, we saw to be the groundwork of habit. Elementary habit would be the better name for what Professor Richet means. Well, the first manifestation of elementary habit is the slow dying away of an impressed movement on the neural matter, and its first effect in consciousness is this so-called elementary memory. But what elementary memory makes us aware of is the just past. The objects we feel in this directly intuited past differ from properly recollected objects. An object which is recollected, in the proper sense of that term, is one which has been absent from consciousness altogether, and now revives anew. It is brought back, recalled, fished up, so to speak, from a reservoir in which, with countless other objects, it lay buried and lost from view. But an object of primary memory is not thus brought back; it never was lost; its date was never cut off in consciousness from that of the immediately present moment. In fact it comes to us as belonging to the rearward portion of the present space of time, and not to the genuine past. In the last chapter we saw that the portion of time which we directly intuit has a breadth of several seconds, a rearward and a forward end, and may be called the specious present. All stimuli whose first nerve-vibrations have not yet ceased seem to be conditions of our getting this feeling of the specious present. They give rise to objects which appear to the mind as events just past.6

When we have been exposed to an unusual stimulus for many minutes or hours, a nervous process is set up which results in the haunting of consciousness by the impression for a long time afterwards. The tactile and muscular feelings of a day of skating or riding, after long disuse of the exercise, will come back to us all through the night. Images of the field of view of the microscope will annoy the observer for hours after an unusually long sitting at the instrument. A thread tied around the finger, an unusual constriction in the clothing, will feel as if still there, long after they have been removed. These revivals (called phenomena of Sinnesgedächtniss by the Germans) have something periodical in their nature.7 They show that profound rearrangements and slow settlings into a new equilibrium are going on in the neural substance, and they form the transition to that more peculiar and proper phenomenon of memory, of which the rest of this chapter must treat. The first condition which makes a thing susceptible of recall after it has been forgotten is that the original impression of it should have been prolonged enough to give rise to a recurrent image of it, as distinguished from one of those primary after-images which very fleeting impressions may leave behind, and which contain in themselves no guarantee that they will ever come back after having once faded away.8 A certain length of stimulation seems demanded by the inertia of the nerve-substance. Exposed to a shorter influence, its modification fails to 'set,' and it retains no effective tendency to fall again into the same form of vibration at which the original feeling was due. This, as I said at the outset, may be the reason why only 'substantive' and not 'transitive' states of mind are as a rule recollected, at least as independent things. The transitive states pass by too quickly.

Analysis of the Phenomenon of Memory.

Memory proper, or secondary memory as it might be styled, is the knowledge of a former state of mind after it has already once dropped from consciousness; or rather it is the knowledge of an event, or fact, of which meantime we have not been thinking, with the additional consciousness that we have thought or experienced it before.

The first element which such a knowledge involves would seem to be the revival in the mind of an image or copy of the original event.9 And it is an assumption made by many writers10 that the revival of an image is all that is needed to constitute the memory of the original occurrence. But such a revival is obviously not a memory, whatever else it may be; it is simply a duplicate, a second event, having absolutely no connection with the first event except that it happens to resemble it. The clock strikes to-day; it struck yesterday; and may strike a million times ere it wears out. The rain pours through the gutter this week; it did so last week; and will do so in sœcula sœculorum. But does the present clock-stroke become aware of the past ones, or the present stream recollect the past stream, because they repeat and resemble them? Assuredly not. And let it not be said that this is because clock-strokes and gutters are physical and not psychical objects; for psychical objects (sensations for example) simply recurring in successive editions will remember each other on that account no more than clock-strokes do. No memory is involved in the mere fact of recurrence. The successive editions of a feeling are so many independent events, each snug in its own skin. Yesterday's feeling is dead and buried; and the presence of to-day's is no reason why it should resuscitate. A farther condition is required before the present image can be held to stand for a past original.

That condition is that the fact imaged be expressly referred to the past, thought as in the past. But how can we think a thing as in the past, except by thinking of the past together with the thing, and of the relation of the two? And how can we think of the past? In the chapter on Time-perception we have seen that our intuitive or immediate consciousness of pastness hardly carries us more than a few seconds backward of the present instant of time. Remoter dates are conceived, not perceived; known symbolically by names, such as 'last week,' '1850;' or thought of by events which happened in them, as the year in which we attended such a school, or met with such a loss. -- So that if we wish to think of a particular past epoch, we must think of a name or other symbol, or else of certain concrete events, associated therewithal. Both must be thought of, to think the past epoch adequately. And to 'refer' any special fact to the past epoch is to think that fact with the names and events which characterize its date, to think it, in short, with a lot of contiguous associates.

But even this would not be memory. Memory requires more than mere dating of a fact in the past. It must be dated in my past. In other words, I must think that I directly experienced its occurrence. It must have that 'warmth and intimacy' which were so often spoken of in the chapter on the Self, as characterizing all experiences 'appropriated' by the thinker as his own.

A general feeling of the past direction in time, then, a particular date conceived as lying along that direction, and defined by its name or phenomenal contents, an event imagined as located therein, and owned as part of my experience, -- such are the elements of every act of memory.

It follows that what we began by calling the 'image,' or 'copy,' of the fact in the mind, is really not there at all in that simple shape, as a separate 'idea.' Or at least, if it be there as a separate idea, no memory will go with it. What memory goes with is, on the contrary, a very complex representation, that of the fact to be recalled plus its associates, the whole forming one 'object' (as explained on page 275, Chapter IX), known in one integral pulse of consciousness (as set forth on pp. 276 ff.) and demanding probably a vastly more intricate brain-process than that on which any simple sensorial image depends.

Most psychologists have given a perfectly clear analysis of the phenomenon we describe. Christian Wolff, for example, writes:

"Suppose you have seen Mevius in the temple, but now afresh in Titus' house. I say you recognize Mevius, that is, are conscious of having seen him before, because, although now you perceive him with your senses along with Titus' house, your imagination produces an image of him along with one of the temple, and of the acts of your own mind reflecting on Mevius in the temple. Hence the idea of Mevius which is reproduced in sense is contained in another series of perceptions than that which formerly contained it, and this difference is the reason why we are conscious of having had it before . . . . For whilst now you see Mevius in the house of Titus, your imagination places him in the temple, and renders you conscious of the state of mind which you found in yourself when you beheld him there. By this you know that you have seen him before, that is, you recognize him. But you recognize him because his idea is now contained in another series of perceptions from that in which you first saw him."11

Similarly James Mill writes:

"In my remembrance of George III., addressing the two houses of parliament, there is, first of all, the mere idea, or simple apprehension, the conception, as it is sometimes called, of the objects. There is combined with this, to make it memory, my idea of my having seen and heard those objects. And this combination is so close that it is not in my power to separate them. I cannot have the idea of George III.; his person and attitude, the paper he held in his hand, the sound of his voice while reading from it; without having the other idea along with it, that of my having been a witness of the scene. . . . If this explanation of the case in which we remember sensations is understood, the explanation of the case in which we remember ideas cannot occasion much of difficulty. I have a lively recollection of Polyphemus's cave, and the actions of Ulysses and the Cyclops, as described by Homer. In this recollection there is, first of all, the ideas, or simple conceptions of the objects and acts; and along with these ideas, and so closely combined as not to be separable, the idea of my having formerly had those same ideas. And this idea of my having formerly had those ideas is a very complicated idea; including the idea of myself of the present moment remembering, and that of myself of the past moment conceiving; and the whole series of the states of consciousness, which intervened between myself remembering, and myself conceiving."12

Memory is then the feeling of belief in a peculiar complex object; but all the elements of this object may be known to other states of belief; nor is there in the particular combination of them as they appear in memory anything so peculiar as to lead us to oppose the latter to other sorts of thought as something altogether sui generis, needing a special faculty to account for it. When later we come to our chapter on Belief we shall see that any represented object which is connected either mediately or immediately with our present sensations or emotional activities tends to be believed in as a reality. The sense of a peculiar active relation in it to ourselves is what gives to an object the characteristic quality of reality, and a merely imagined past event differs from a recollected one only in the absence of this peculiar feeling relation. The electric current, so to speak, between it and our present self does not close. But in their other determinations the re-recollected past and the imaginary past may be much the same. In other words, there is nothing unique in the object of memory, and no special faculty is needed to account for its formation. It is a synthesis of parts thought of as related together, perception, imagination, comparison and reasoning being analogous syntheses of parts into complex objects. The objects of any of these faculties may awaken belief or fail to awaken it; the object of memory is only an object imagined in the past (usually very completely imagined there) to which the emotion of belief adheres.

Memory's Causes.

Such being the phenomenon of memory, or the analysis of its object, can we see how it comes to pass? can we lay bare its causes?

Its complete exercise presupposes two things:

1) The retention of the remembered fact;

2) Its reminiscence, recollection, reproduction, or recall.

Now the cause both of retention and of recollection is the law of habit in the nervous system, working as it does in the 'association of ideas.'

Associationists have long explained recollection by association. James Mill gives an account of it which I am unable to improve upon, unless it might be by translating his word 'idea' into 'thing thought of,' or 'object,' as explained so often before.

"There is," he says, "a state of mind familiar to all men, in which we are said to remember. In this state it is certain we have not in the mind the idea which we are trying to have in it.13 How is it, then, that we proceed in the course of our endeavor, to procure its introduction into the mind? If we have not the idea itself, we have certain ideas connected with it. We run over those ideas, one after another, in hopes that some one of them will suggest the idea we are in quest of; and if any one of them does, it is always one so connected with it as to call it up in the way of association. I meet an old acquaintance, whose name I do not remember, and wish to recollect. I run over a number of names, in hopes that some of them may be associated with the idea of the individual. I think of all the circumstances in which I have seen him engaged; the time when I knew him, the persons along with whom I knew him, the things he did, or the things he suffered; and, if I chance upon any idea with which the name is associated, then immediately I have the recollection; if not, my pursuit of it is vain.14 There is another set of cases, very familiar, but affording very important evidence on the subject. It frequently happens that there are matters which we desire not to forget. What is the contrivance to which we have recourse for preserving the memory -- that is, for making sure that it will be called into existence, when it is our wish that it should? All men invariably employ the same expedient. They endeavor to form an association between the idea of the thing to be remembered, and some sensation, or some idea, which they know beforehand will occur at or near the time when they wish the remembrance to be in their minds. If this association is formed, and the association or idea with which it has been formed occurs; the sensation, or idea, calls up the remembrance; and the object of him who formed the association is attained. To use a vulgar instance: a man receives a commission from his friend, and, that he may not forget it, ties a knot in his handkerchief. How is this fact to be explained? First of all, the idea of the commission is associated with the making of the knot. Next, the handkerchief is a thing which it is known beforehand will be frequently seen, and of course at no great distance of time from the occasion on which the memory is desired. The handkerchief being seen, the knot is seen, and this sensation recalls the idea of the commission, between which and itself the association had been purposely formed."15

In short, we make search in our memory for a forgotten idea, just as we rummage our house for a lost object. In both cases we visit what seems to us the probable neighborhood of that which we miss. We turn over the things under which, or within which, or alongside of which, it may possibly be; and if it lies near them, it soon comes to view. But these matters, in the case of a mental object sought, are nothing but its associates. The machinery of recall is thus the same as the machinery of association, and the machinery of association, as we know, is nothing but the elementary law of habit in the nerve-centres.

And this same law of habit is the machinery of retention also. Retention means liability to recall, and it means nothing more than such liability. The only proof of there being retention is that recall actually takes place. The retention of an experience is, in short, but another name for the possibility of thinking it again, or the tendency to think it again, with its past surroundings. Whatever accidental cue may turn this tendency into an actuality, the permanent ground of the tendency itself lies in the organized neural paths by which the cue calls up the experience on the proper occasion, together with its past associates, the sense that the self was there, the belief that it really happened, etc., etc., just as previously described. When the recollection is of the 'ready' sort, the resuscitation takes place the instant the occasion arises; when it is slow, resuscitation comes after delay. But be the recall prompt or slow, the condition which makes it possible at all (or in other words, the 'retention' of the experience) is neither more nor less then the brain-paths which associate the experience with the occasion and cue of the recall. When slumbering, these paths are the condition of retention; when active, they are the condition of recall. Fig45

A simple scheme will now make the whole cause of memory plain. Let n be a past event; o its 'setting' (concomitants, date, self present, warmth and intimacy, etc., etc., as already set forth); and m some present thought or fact which may appropriately become the occasion of its recall. Let the nerve-centres, active in the thought of m, n, and o, be represented by M, N, and O, respectively; then the existence of the paths M-N and N-O will be the fact indicated by the phrase 'retention of the event n in the memory,' and the excitement of the brain along these paths will be the condition of the event n's actual recall. The retention of n, it will be observed, is no mysterious storing up of an 'idea' in an unconscious state. It is not a fact of the mental order at all. It is a purely physical phenomenon, a morphological feature, the presence of these 'paths,' namely, in the finest recesses of the brain's tissue. The recall or recollection, on the other hand, is a psychophysical phenomenon, with both a bodily and a mental side. The bodily side is the functional excitement of the tracts and paths in question; the mental side is the conscious vision of the past occurrence, and the belief that we experienced it before.

These habit-worn paths of association are a clear rendering of what authors mean by 'predispositions,' 'vestiges,' 'traces,' etc., left in the brain by past experience. Most writers leave the nature of these vestiges vague; few think of explicitly assimilating them to channels of association. Dr. Maudsley, for example, writes:

"When an idea which we have once had is excited again, there is a reproduction of the same nervous current, with the conscious addition that it is a reproduction -- it is the same idea plus the consciousness that it is the same. The question then suggests itself, What is the physical condition of this consciousness? What is the modification of the anatomical substrata of fibres and cells, or of their physiological activity, which is the occasion of this plus element in the reproduced idea? It may be supposed that the first activity did leave behind it, when it subsided, some after-effect, some modification of the nerve-element, whereby the nerve-circuit was disposed to fall again readily into the same action; such disposition appearing in consciousness as recognition or memory. Memory is, in fact, the conscious phase of this physiological disposition when it becomes active or discharges its functions on the recurrence of the particular mental experience. To assist our conception of what may happen, let us suppose the individual nerve-elements to be endowed with their own consciousness, and let us assume them to be, as I have supposed, modified in a certain way by the first experience; it is hard to conceive that when they fall into the same action on another occasion they should not recognize or remember it; for the second action is a reproduction of the first, with the addition of what it contains from the after-effects of the first. As we have assumed the process to be conscious, this reproduction with its addition would be a memory or remembrance."16

In this passage Dr. Maudsley seems to mean by the 'nerve-element,' or 'anatomical substratum of fibres and cells,' something that corresponds to the N of our diagram. And the 'modification' he speaks of seems intended to be understood as an internal modification of this same particular group of elements. Now the slightest reflection will convince anyone that there is no conceivable ground for supposing that with the mere re-excitation of N there should arise the 'conscious addition' that it is a re-excitation. The two excitations are simply two excitations, their consciousnesses are two consciousnesses, they have nothing to do with each other. And a vague 'modification,' supposed to be left behind by the first excitation, helps us not a whit. For, according to all analogy, such a modification can only result in making the next excitation more smooth and rapid. This might make it less conscious, perhaps, but could not endow it with any reference to the past. The gutter is worn deeper by each successive shower, but not for that reason brought into contact with previous showers. Psychology (which Dr. Maudsley in his next sentence says "affords us not the least help in this matter") puts us on the track of an at least possible brain-explanation. As it is the setting o of the idea, when it recurs, which makes us conscious of it as past, so it can be no intrinsic modification of the 'nerve-element' N which is the organic condition of memory, but something extrinsic to it altogether, namely, its connections with those other nerve-elements which we called O -- that letter standing in the scheme for the cerebral substratum of a great plexus of things other than the principal event remembered, dates, names, concrete surroundings, realized intervals, and what not. The 'modification' is the formation in the plastic nerve-substance of the system of associative paths between N and 0.

The only hypothesis, in short, to which the facts of inward experience give countenance is that the brain-tracts excited by the event proper, and those excited in its recall, are in part different from each other. If we could revive the past event without any associates we should exclude the possibility of memory, and simply dream that we were undergoing the experience as if for the first time.17 Wherever, in fact, the recalled event does appear without a definite setting, it is hard to distinguish it from a mere creation of fancy. But in proportion as its image lingers and recalls associates which gradually become more definite, it grows more and more distinctly into a remembered thing. For example, I enter a friend's room and see on the wall a painting. At first I have the strange, wondering consciousness, 'surely I have seen that before,' but when or how does not become clear. There only clings to the picture a sort of penumbra of familiarity, -- when suddenly I exclaim: "I have it, it is a copy of part of one of the Fra Angelicos in the Florentine Academy -- I recollect it there!" But the motive to the recall does not lie in the fact that the brain-tract now excited by the painting was once before excited in a similar way; it lies simply and solely in the fact that with that brain-tract other tracts also are excited: those which sustain my friend's room with all its peculiarities, on the one hand; those which sustain the mental image of the Florence Academy, on the other hand, with the circumstances of my visit there; and finally those which make me (more dimly) think of the years I have lived through between these two times. The result of this total brain-disturbance is a thought with a peculiar object, namely, that I who now stand here with this picture before me, stood so many years ago in the Florentine Academy looking at its original.

M. Taine has described the gradual way in which a mental image develops into an object of memory, in his usual vivid fashion. He says:

"I meet casually in the street a person whose appearance I am acquainted with, and say to myself at once that I have seen him before. Instantly the figure recedes into the past, and wavers about there vaguely, without at once fixing itself in any spot. It persists in me for some time, and surrounds itself with new details. 'When I saw him he was bare-headed, with a working-jacket on, painting in a studio; he is so-and-so, of such-and-such a street. But when was it? It was not yesterday, nor this week, nor recently. I have it: he told me that he was waiting for the first leaves to come out to go into the country. It was before the spring. But at what exact date? I saw, the same day, people carrying branches in the streets and omnibuses: it was Palm Sunday!' Observe the travels of the internal figure, its various shiftings to front and rear along the line of the past; each of these mental sentences has been a swing of the balance. When confronted with the present sensation and with the latent swarm of indistinct images which repeat our recent life, the figure first recoiled suddenly to an indeterminate distance. Then, completed by precise details, and confronted with all the shortened images by which we sum up the proceedings of a day or a week, it again receded beyond the present day, beyond yesterday, the day before, the week, still farther, beyond the ill-defined mass constituted by our recent recollections. Then something said by the painter was recalled, and it at once receded again beyond an almost precise limit, which is marked by the image of the green leaves and denoted by the word spring. A moment afterwards, thanks to a new detail, the recollection of the branches, it has shifted again, but forward this time, not backward; and, by a reference to the calendar, is situated at a precise point, a week further back than Easter, and five weeks nearer than the carnival, by the double effect of the contrary impulsions, pushing it, one forward and the other backward, and which are, at a particular moment, annulled by one another."18

The Conditions of Goodness in Memory.

The remembered fact being n, then, the path N -- O is what arouses for n its setting when it is recalled, and makes it other than a mere imagination. The path M -- N, on the other hand, gives the cue or occasion of its being recalled at all. Memory being thus altogether conditioned on brain-paths, its excellence in a given individual will depend partly on the number and partly on the persistence of these paths.

The persistence or permanence of the paths is a physiological property of the brain-tissue of the individual, whilst their number is altogether due to the facts of his mental experience. Let the quality of permanence in the paths be called the native tenacity, or physiological retentiveness. This tenacity differs enormously from infancy to old age, and from one person to another. Some minds are like wax under a seal -- no impression, however disconnected with others, is wiped out. Others, like a jelly, vibrate to every touch, but under usual conditions retain no permanent mark. These latter minds, before they can recollect a fact, must weave it into their permanent stores of knowledge. They have no desultory memory. Those persons, on the contrary, who retain names, dates and addresses, anecdotes, gossip, poetry, quotations, and all sorts of miscellaneous facts, without an effort, have desultory memory in a high degree, and certainly owe it to the unusual tenacity of their brain-substance for any path once formed therein. No one probably was ever effective on a voluminous scale without a high degree of this physiological retentiveness. In the practical as in the theoretic life, the man whose acquisitions stick is the man who is always achieving and advancing, whilst his neighbors, spending most of their time in relearning what they once knew but have forgotten, simply hold their own. A Charlemagne, a Luther, a Leibnitz, a Walter Scott, any example, in short, of your quarto or folio editions of mankind, must needs have amazing retentiveness of the purely physiological sort. Men without this retentiveness may excel in the quality of their work at this point or at that, but will never do such mighty sums of it, or be influential contemporaneously on such a scale.19

But there comes a time of life for all of us when we can do no more than hold our own in the way of acquisitions, when the old paths fade as fast as the new ones form in our brain, and when we forget in a week quite as much as we can learn in the same space of time. This equilibrium may last many, many years. In extreme old age it is upset in the reverse direction, and forgetting prevails over acquisition, or rather there is no acquisition. Brain-paths are so transient that in the course of a few minutes of conversation the same question is asked and its answer forgotten half a dozen times. Then the superior tenacity of the paths formed in childhood becomes manifest: the dotard will retrace the facts of his earlier years after he has lost all those of later date.

So much for the permanence of the paths. Now for their number.

It is obvious that the more there are of such paths as M -- N in the brain, and the more of such possible cues or occasions for the recall of n in the mind, the prompter and surer, on the whole, the memory of n will be, the more frequently one will be reminded of it, the more avenues of approach to it one will possess. In mental terms, the more other facts a fact is associated with in the mind, the better possession of it our memory retains. Each of its associates becomes a hook to which it hangs, a means to fish it up by when sunk beneath 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 and the same amount of mere native tenacity, the one who THINKS over his experiences most, and weaves them into systematic relations with each other, will be the one with the best memory. We see examples of this on every hand. Most men have a good memory for facts connected with their own pursuits. The college athlete who remains a dunce at his books will astonish you by his knowledge of men's 'records' in various feats and games, and will be 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 amazes outsiders, but which the amount of thinking they bestow on these subjects easily explains. The great memory for facts which a Darwin and a Spencer reveal in their books is not incompatible with the possession on their part of a brain 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 encyclopædic as his erudition may coexist with the latter, and hide, as it were, in the interstices of its web. Those who have had much to do with scholars and savants will readily think of examples of the class of mind I mean.

In a system, every fact is connected with every other by some thought-relation. The consequence is that every fact is retained by the combined suggestive power of all the other facts in the system, and forgetfulness is well-nigh impossible.

The reason why cramming is such a bad mode of study is now made clear. I mean by cramming that way of preparing for examinations by committing 'points' to memory during a few hours or days of intense application immediately preceding the final ordeal, little or no work having been performed during the previous course of the term. Things learned thus in a few hours, on one occasion, for one purpose, cannot possibly have formed many associations with other things in the mind. Their brain-processes are led into by few paths, and are relatively little liable to be awakened again. Speedy oblivion is the almost inevitable fate of all that is committed to memory in this simple way. Whereas, on the contrary, the same materials taken in gradually, day after day, recurring in different contexts, considered in various relations, associated with other external incidents, and repeatedly reflected on, grow into such a system, form such connections with the rest of the mind's fabric, lie open to so many paths of approach, that they remain permanent possessions. This is the intellectual reason why habits of continuous application should be enforced in educational establishments. Of course there is no moral turpitude in cramming. If it led to the desired end of secure learning it would be infinitely the best method of study. But it does not; and students themselves should understand the reason why.

One's Native Retentiveness is Unchangeable.

It will now appear clear that all improvement of the memory lies in the line of ELABORATING THE ASSOCIATES of each of the several things to be remembered. No amount of culture would seem capable of modifying a man's GENERAL retentiveness. This is a physiological quality, given once for all with his organization, and which he can never hope to change. It differs no doubt in disease and health; and it is a fact of observation that it is better in fresh and vigorous hours than when we are fagged or ill. We may say, then, that a man's native tenacity will fluctuate somewhat with his hygiene, and that whatever is good for his tone of health will also be good for his memory. We may even say that whatever amount of intellectual exercise is bracing to the general tone and nutrition of the brain will also be profitable to the general retentiveness. But more than this we cannot say; and this, it is obvious, is far less than most people believe.

It is, in fact, commonly thought that certain exercises, systematically repeated, will strengthen, not only a man's remembrance of the particular facts used in the exercises, but his faculty for remembering facts at large. And a plausible case is always made out by saying that practice in learning words by heart makes it easier to learn new words in the same way.20 If this be true, then what I have just said is false, and the whole doctrine of memory as due to 'paths' must be revised. But I am disposed to think the alleged fact untrue. I have carefully questioned several mature actors on the point, and all have denied that the practice of learning parts has made any such difference as is alleged. What it has done for them is to improve their power of studying a part systematically. Their mind is now full of precedents in the way of intonation, emphasis, gesticulation; the new words awaken distinct suggestions and decisions; are caught up, in fact, into a pre-existing net-work, like the merchant's prices, or the athlete's store of 'records,' and are recollected easier, although the mere native tenacity is not a whit improved, and is usually, in fact, impaired by age. It is a case of better remembering by better thinking. Similarly when schoolboys improve by practice in ease of learning by heart, the improvement will, I am sure, be always found to reside in the mode of study of the particular piece (due to the greater interest, the greater suggestiveness, the generic similarity with other pieces, the more sustained attention, etc., etc.), and not at all to any enhancement of the brute retentive power.

The error I speak of pervades an otherwise useful and judicious book, 'How to Strengthen the Memory,' by Dr. Holbrook of New York.21 The author fails to distinguish between the general physiological retentiveness and the retention of particular things, and talks as if both must be benefited by the same means.

"I am now treating," he says, "a case of loss of memory in a person advanced in years, who did not know that his memory had failed most remarkably till I told him of it. He is making vigorous efforts to bring it back again, and with partial success. The method pursued is to spend two hours daily, one in the morning and one in the evening, in exercising this faculty. The patient is instructed to give the closest attention to all that he learns, so that it shall be impressed on his mind clearly. He is asked to recall every evening all the facts and experiences of the day, and again the next morning. Every name heard is written down and impressed on his mind clearly, and an effort made to recall it at intervals. Ten names from among public men are ordered to be committed to memory every week. A verse of poetry is to be learned, also a verse from the Bible, daily. He is asked to remember the number of the page in any book where any interesting fact is recorded. These and other methods are slowly resuscitating a failing memory."22

I find it very hard to believe that the memory of the poor old gentleman is a bit the better for all this torture except in respect of the particular facts thus wrought into it, the occurrences attended to and repeated on those days, the names of those politicians, those Bible verses, etc., etc. In another place Dr. Holbrook quotes the account given by the late Thurlow Weed, journalist and politician, of his method of strengthening his memory.

"My memory was a sieve. I could remember nothing. Dates, names, appointments, faces -- everything escaped me. I said to my wife, 'Catherine, I shall never make a successful politician, for I cannot remember, and that is a prime necessity of politicians.' My wife told me I must train my memory. So when I came home that night, I sat down alone and spent fifteen minutes trying silently to recall with accuracy the principal events of the day. I could remember but little at first; now I remember that I could not then recall what I had for breakfast. After a few days' practice I found I could recall more. Events came back to me more minutely, more accurately, and more vividly than at first. After a fortnight or so of this, Catherine said, 'Why don't you relate to me the events of the day, instead of recalling them to yourself? It would be interesting, and my interest in it would be a stimulus to you.' Having great respect for my wife's opinion, I began a habit of oral confession, as it were, which was continued for almost fifty years. Every night, the last thing before retiring, I told her everything I could remember that had happened to me or about me during the day. I generally recalled the dishes I had had for breakfast, dinner, and tea; the people I had seen and what they had said; the editorials I had written for my paper, giving her a brief abstract of them. I mentioned all the letters I had sent and received, and the very language used, as nearly as possible; when I had walked or ridden -- I told her everything that had come within my observation. I found I could say my lessons better and better every year, and instead of the practice growing irksome, it became a pleasure to go over again the events of the day. I am indebted to this discipline for a memory of somewhat unusual tenacity, and I recommend the practice to all who wish to store up facts, or expect to have much to do with influencing men."23

I do not doubt that Mr. Weed's practical command of his past experiences was much greeter after fifty years of this heroic drill than it would have been without it. Expecting to give his account in the evening, he attended better to each incident of the day, named and conceived it differently, set his mind upon it, and in the evening went over it again. He did more thinking about it, and it stayed with him in consequence. But I venture to affirm pretty confidently (although I know how foolish it often is to deny a fact on the strength of a theory) that the same matter, casually attended to and not thought about, would have stuck in his memory no better at the end than at the beginning of his years of heroic self-discipline. He had acquired a better method of noting and recording his experiences, but his physiological retentiveness was probably not a bit improved.24

All improvement of memory consists, then, in the improvement of one's habitual methods of recording facts. In the traditional terminology methods are divided into the mechanical, the ingenious, and the judicious.

The mechanical methods consist in the intensification, prolongation, and repetition of the impression to be remembered. The modern method of teaching children to read by blackboard work, in which each word is impressed by the four-fold channel of eye, ear, voice, and hand, is an example of an improved mechanical method of memorizing.

Judicious methods of remembering things are nothing but logical ways of conceiving them and working them into rational systems, classifying them, analyzing them into parts, etc., etc. All the sciences are such methods.

Of ingenious methods, many have been invented, under the name of technical memories. By means of these systems it is often possible to retain entirely disconnected facts, lists of names, numbers, and so forth, so multitudinous as to be entirely unrememberable in a natural way. The method consists usually in a framework learned mechanically, of which the mind is supposed to remain in secure and permanent possession. Then, whatever is to be remembered is deliberately associated by some fanciful analogy or connection with some part of this framework, and this connection thenceforward helps its recall. The best known and most used of these devices is the figure-alphabet. To remember numbers, e.g., a figure-alphabet is first formed, in which each numerical digit is represented by one or more letters. The number is then translated into such letters as will best make a word, if possible a word suggestive of the object to which the number belongs. The word will then be remembered when the numbers alone might be forgotten.

"The most common figure-alphabet is this:

1, 2, 3, 4, 5, 6, 7, 8, 9, 0.

t, n, m, r, l, sh, g, f, b, s,

d, j, k, v, p, c,

ch, c, z,

g, qu.

"To briefly show its use, suppose it is desired to fix 1142 feet in a second as the velocity of sound: t, t, r, n, are the letters and order required. Fill up with vowels forming a phrase, like 'tight run' and connect it by some such flight of the imagination as that if a man tried to keep up with the velocity of sound, he would have a tight run. When you recall this a few days later great care must be taken not to get confused with the velocity of light, nor to think he had a hard run which would be 3000 feet too fast."25

Dr. Pick and others use a system which consists in linking together any two ideas to be remembered by means of an intermediate idea which will be suggested by the first and suggest the second, and so on through the list.

Thus,

"Let us suppose that we are to retain the following series of ideas: garden, hair, watchman, philosophy, copper, etc. . . . We can combine the ideas in this manner: garden, plant, hair of plant -- hair; hair, bonnet, watchman; --watchman, wake, study, philosophy; philosophy, chemistry, copper; etc. etc." (Pick.)26

It is matter of popular knowledge that an impression is remembered the better in proportion as it is

1) More recent;

2) More attended to; and

3) More often repeated.

The effect of recency is all but absolutely constant. Of two events of equal significance the remoter one will be the one more likely to be forgotten. The memories of childhood which persist in old age can hardly be compared with the events of the day or hour which are forgotten, for these latter are trivial once-repeated things, whilst the childish reminiscences have been wrought into us during the retrospective hours of our entire intervening life. Other things equal, at all times of life recency promotes memory. The only exception I can think of is the unaccountable memory of certain moments of our childhood, apparently not fitted by their intrinsic interest to survive, but which are perhaps the only incidents we can remember out of the year in which they occurred. Everybody probably has isolated glimpses of certain hours of his nursery life, the position in which he stood or sat, the light of the room, what his father or mother said, etc. These moments so oddly selected for immunity from the tooth of time probably owe their good fortune to historical peculiarities which it is now impossible to trace. Very likely we were reminded of them again soon after they occurred; that became a reason why we should again recollect them, etc., so that at last they became ingrained.

The attention which we lend to an experience is proportional to its vivid or interesting character; and it is a notorious fact that what interests us most vividly at the time is, other things equal, what we remember best. An impression may be so exciting emotionally as almost to leave a scar upon the cerebral tissues; and thus originates a pathological delusion. "A woman attacked by robbers takes all the men whom she sees, even her own son, for brigands bent on killing her. Another woman sees her child run over by a horse; no amount of reasoning, not even the sight of the living child, will persuade her that he is not killed. A woman called 'thief' in a dispute remains convinced that every one accuses her of stealing (Esquirol). Another, attacked with mania at the sight of the fires in her street during the Commune, still after six months sees in her delirium flames on every side about her (Luys), etc., etc."27

On the general effectiveness of both attention and repetition I cannot do better than copy what M. Taine has written:

"If we compare different sensations, images, or ideas, we find that their aptitudes for revival are not equal. A large number of them are obliterated, and never reappear through life; for instance, I drove through Paris a day or two ago, and though I saw plainly some sixty or eighty new faces, I cannot now recall any one of them; some extraordinary circumstance, a fit of delirium, or the excitement of haschish would be necessary to give them a chance of revival. On the other hand, there are sensations with a force of revival which nothing destroys or decreases. Though, as a rule, time weakens and impairs our strongest sensations, these reappear entire and intense, without having lost a particle of their detail, or any degree of their force. M. Brierre de Boismont, having suffered when a child from a disease of the scalp, asserts that 'after fifty-five years have elapsed he can still feel his hair pulled out under the treatment of the skull-cap.' -- For my own part, after thirty years, I remember feature for feature the appearance of the theatre to which I was taken for the first time. From the third row of boxes, the body of the theatre appeared to me an immense well, red and flaming, swarming with heads; below, on the right, on a narrow floor, two men and a woman entered, went out, and re-entered, made gestures, and seemed to me like lively dwarfs: to my great surprise, one of these dwarfs fell on his knees, kissed the lady's hand, then hid behind a screen; the other, who was coming in, seemed angry, and raised his arm. I was then seven, I could understand nothing of what was going on; but the well of crimson velvet was so crowded, gilded, and bright, that after a quarter of an hour I was, as it were, intoxicated, and fell asleep.

"Every one of us may find similar recollections in his memory, and may distinguish in them a common character. The primitive impression has been accompanied by an extraordinary degree of attention, either as being horrible or delightful, or as being new, surprising, and out of proportion to the ordinary run of our life; this it is we express by saying that we have been strongly impressed; that we were absorbed, that we could not think of anything else; that our other sensations were effaced; that we were pursued all the next day by the resulting image; that it beset us, that we could not drive it away; that all distractions were feeble beside it. It is by force of this disproportion that impressions of childhood are so persistent; the mind being quite fresh, ordinary objects and events are surprising. At present, after seeing so many large halls and full theatres, it is impossible for me, when I enter one, to feel swallowed up, engulfed, and, as it were, lost in a huge dazzling well. The medical man of sixty, who has experienced much suffering, both personally and in imagination, would be less upset now by a surgical operation than when he was a child.

"Whatever may be the kind of attention, voluntary or involuntary, it always acts alike; the image of an object or event is capable of revival, and of complete revival, in proportion to the degree of attention with which we have considered the object or event. We put this rule in practice at every moment in ordinary life. If we are applying ourselves to a book or are in lively conversation, while an air is being sung in the adjoining room, we do not retain it; we know vaguely that there is singing going on, and that is all. We then stop our reading or conversation, we lay aside all internal preoccupations and external sensations which our mind or the outer world can throw in our way; we close our eyes, we cause a silence within and about us, and, if the air is repeated, we listen. We say then that we have listened with all our ears, that we have applied our whole minds. If the air is a fine one, and has touched us deeply, we add that we have been transported, uplifted, ravished, that we have forgotten the world and ourselves; that for some minutes our soul was dead to all but sounds . . . .

"This exclusive momentary ascendency of one of our states of mind explains the greater durability of its aptitude for revival and for more complete revival. As the sensation revives in the image, the image reappears with a force proportioned to that of the sensation. What we meet with in the first state is also to be met with in the second, since the second is but a revival of the first. So, in the struggle for life, in which all our images are constantly engaged, the one furnished at the outset with most force retains in each conflict, by the very law of repetition which gives it being, the capacity of treading down its adversaries; this is why it revives, incessantly at first, then frequently, until at last the laws of progressive decay, and the continual accession of new impressions bake away its preponderance, and its competitors, finding a clear field, are able to develop in their turn.

"A second cause of prolonged revivals is repetition itself. Every one knows that to learn a thing we must not only consider it attentively, but consider it repeatedly. We say as to this in ordinary language, that an impression many times renewed is imprinted more deeply and exactly on the memory. This is how we contrive to retain a language, airs of music, passages of verse or prose, the technical terms and propositions of a science, and still more so the ordinary facts by which our conduct is regulated. When, from the form and color of a currant-jelly, we think of its taste, or, when tasting it with our eyes shut, we magine [sic] its red tint and the brilliancy of a quivering slice, the images in our mind are brightened by repetition. Whenever we eat, or drink, or walk, or avail ourselves of any of our senses, or commence or continue any action whatever, the same thing happens. Every man and every animal thus possesses at every moment of life a certain stock of clear and easily reviving images, which had their source in the past in a confluence of numerous experiences, and are now fed by a flow of renewed experiences. When I want to go from the Tuileries to the Panthéon, or from my study to the dining-room, I foresee at every turn the colored forms which will present themselves to my sight; it is otherwise in the case of a house where I have spent two hours, or of a town where I have stayed three days; after ten years have elapsed the images will be vague, full of blanks, sometimes they will not exist, and I shall have to seek my way or shall lose myself. -- This new property of images is also derived from the first. As every sensation tends to revive in its image, the sensation twice repeated will leave after it a double tendency, that is, provided the attention be as great the second time as the first; usually this is not the case, for, the novelty diminishing, the interest diminishes; but if other circumstances renew the interest, or if the will renovates the attention, the incessantly increasing tendency will incessantly increase the chances of the resurrection and integrity of the image."28

If a phenomenon is met with, however, too often, and with too great a variety of contexts, although its image is retained and reproduced with correspondingly great facility, it fails to come up with any one particular setting, and the projection of it backwards to a particular past date consequently does not come about. We recognize but do not remember it -- its associates form too confused a cloud. No one is said to remember, says Mr. Spencer,

"that the object at which he looks has an opposite side; or that a certain modification of the visual impression implies a certain distance; or that the thing he sees moving about is a live animal. To ask a man whether he remembers that the sun shines, that fire burns, that iron is hard, would be a misuse of language. Even the almost fortuitous connections among our experiences cease to be classed as memories when they have become thoroughly familiar. Though, on hearing the voice of some unseen person slightly known to us, we say we recollect to whom the voice belongs, we do not use the same expression respecting the voices of those with whom we live. The meanings of words which in childhood have to be consciously recalled seem in adult life to be immediately present."29

These are cases where too many paths, leading to too diverse associates, block each other's way, and all that the mind gets along with its object is a fringe of felt familiarity or sense that there are associates. A similar result comes about when a definite setting is only nascently aroused. We then feel that we have seen the object already, but when or where we cannot say, though we may seem to ourselves to be on the brink of saying it. That nascent cerebral excitations can effect consciousness with a sort of sense of the imminence of that which stronger excitations would make us definitely feel, is obvious from what happens when we seek to remember a name. It tingles, it trembles on the verge, but does not come. Just such a tingling and trembling of unrecovered associates is the penumbra of recognition that may surround any experience and make it seem familiar, though we know not why.30

There is a curious experience which everyone seems to have had -- the feeling that the present moment in its completeness has been experienced before -- we were saying just this thing, in just this place, to just these people, etc. This 'sense of pre-existence' has been treated as a great mystery and occasioned much speculation. Dr. Wigan considered it due to a dissociation of the action of the two hemispheres, one of them becoming conscious a little later than the other, but both of the same fact.31 I must confess that the quality of mystery seems to me a little strained. I have over and over again in my own case succeeded in resolving the phenomenon into a case of memory, so indistinct that whilst some past circumstances are presented again, the others are not. The dissimilar portions of the past do not arise completely enough at first for the date to be identified. All we get is the present scene with a general suggestion of pastness about it. That faithful observer, Prof. Lazarus, interprets the phenomenon the same way;32 and it is noteworthy that just as soon as the past context grows complete and distinct the emotion of weirdness fades from the experience.

Exact Measurements of Memory

have recently been made in Germany. Professor Ebbinghaus, in a really heroic series of daily observations of more than two years' duration, examined the powers of retention and reproduction. He learned lists of meaningless syllables by heart, and tested his recollection of them from day to day. He could not remember more than 7 after a single reading. It took, however, 16 readings to remember 12, 44 readings to remember 24, and 55 readings to remember 26 syllables, the moment of 'remembering' being here reckoned as the first moment when the list could be recited without a fault.33 When a 16-syllable list was read over a certain number of times on one day, and then studied on the day following until remembered, it was found that the number of seconds saved in the study on the second day was proportional to the number of readings on the first -- proportional, that is, within certain rather narrow limits, for which see the text.34 No amount of repetition spent on nonsense-verses over a certain length enabled Dr. Ebbinghaus to retain them without error for 24 hours. In forgetting such things as these lists of syllables, the loss goes on very much more rapidly at first than later on. He measured the loss by the number of seconds required to relearn the list after it had been once learned. Roughly speaking, if it took a thousand seconds to learn the list, and five hundred to relearn it, the loss between the two learnings would have been one half. Measured in this way, full half of the forgetting seems to occur within the first half-hour, whilst only four fifths is forgotten at the end of a month. The nature of this result might have been anticipated, but hardly its numerical proportions. Dr. Ebbinghaus says:

"The initial rapidity, as well as the final slowness, as these were ascertained under certain experimental conditions and for a particular individual, . . . may well surprise us. An hour after the work of learning had ceased, forgetting was so far advanced that more than half of the original work had to be applied again before the series of syllables could once more be reproduced. Eight hours later two thirds of the original labor had to be applied. Gradually, however, the process of oblivion grew slower, so that even for considerable stretches of time the losses were but barely ascertainable. After 24 hours a third, after 6 days a fourth, and after a whole month a good fifth of the original labor remain in the shape of its after-effects, and made the relearning by so much the more speedy."35

But the most interesting result of all those reached by this author relates to the question whether ideas are recalled only by those that previously came immediately before them, or whether an idea can possibly recall another idea with which it was never in immediate contact, without passing through the intermediate mental links. The question is of theoretic importance with regard to the way in which the process of 'association of ideas' must be conceived; and Dr. Ebbinghaus's attempt is as successful as it is original, in bringing two views, which seem at first sight inaccessible to proof, to a direct practical test, and giving the victory to one of them. His experiments conclusively show that an idea is not only 'associated' directly with the one that follows it, and with the rest through that, but that it is directly associated with all that are near it, though in unequal degrees. He first measured the time needed to impress on the memory certain lists of syllables, and then the time needed to impress lists of the same syllables with gaps between them. Thus, representing the syllables by numbers, if the first list were 1, 2, 3, 4, . . . 13, 14, 15, 16, the second would be 1, 3, 5, . . .15, 2, 4, 6, . . .16, and so forth, with many variations.

Now, if 1 and 3 in the first list were learned in that order merely by 1 calling up 2, and by 2 calling up 3, leaving out the 2 ought to leave 1 and 3 with no tie in the mind; and the second list ought to take as much time in the learning as if the first list had never been heard of. If, on the other hand, 1 has a direct influence on 3 as well as on 2, that influence should be exerted even when 2 is dropped out; and a person familiar with the first list ought to learn the second one more rapidly than otherwise he could. This latter case is what actually occurs; and Dr. Ebbinghaus has found that syllables originally separated by as many as seven intermediaries still reveal, by the increased rapidity with which they are learned in order, the strength of the tie that the original learning established between them, over the heads, so to speak, of all the rest. These last results ought to make us careful, when we speak of nervous 'paths,' to use the word in no restricted sense. They add one more fact to the set of facts which prove that association is subtler than consciousness, and that a nerve-process may, without producing consciousness, be effective in the same way in which consciousness would have seemed to be effective if it had been there.36 Evidently the path from 1
to 3 (omitting 2 from consciousness) is facilitated, broadened perhaps, by the old path from 1 to 3 through 2 -- only the component which shoots round through this latter way is too feeble to let 2 be thought as a distinct object.

Mr. Wolfe, in his experiments on recognition, used vibrating metal tongues.

"These tongues gave tones differing by 2 vibrations only in the two lower octaves, and by 4 vibrations in the three higher octaves. In the first series of experiments a tone was selected, and, after sounding it for one second, a second tone was sounded, which was either the same as the first, or different from it by 4, 8, or 12 vibrations in different series. The person experimented upon was to answer whether the second tone was the same as the first, thus showing that he recognized it, or whether it was different, and, if so, whether it was higher or lower. Of course, the interval of time between the two tones was an important factor. The proportionate number of correct judgments, and the smallness of the difference of the vibration-rates of the two tones, would measure the accuracy of the tone-memory. It appeared that one could tell more readily when the two tones were alike than when they were different, although in both cases the accuracy of the memory was remarkably good. . . . The main point is the effect of the time-interval between the tone and its reproduction. This was varied from 1 second to 30 seconds, or even to 60 seconds or 120 seconds in some experiments. The general result is, that the longer the interval, the smaller are the chances that the tone will be recognized; and this process of forgetting takes place at first very rapidly, and then more slowly. . . . This law is subject to considerable variations, one of which seems to be constant and is peculiar; namely, there seems to be a rhythm in the memory itself, which, after falling, recovers slightly, and then fades out again."37

This periodical renewal of acoustic memory would seem to be an important element in the production of the agreeableness of certain rates of recurrence in sound.

Forgetting.

In the practical use of our intellect, forgetting is as important a function as recollecting.

Locke says, in a memorable page of his dear old book:

"The memory of some men, it is true, is very tenacious, even to a miracle; but yet there seems to be a constant decay of all our ideas, even of those which are struck deepest, and in minds the most retentive; so that if they be not sometimes renewed by repeated exercise of the senses, or reflection on those kinds of objects which at first occasioned them, the print wears out, and at last there remains nothing to be seen. Thus the ideas, as well as children, of our youth, often die before us; and our minds represent to us those tombs to which we are fast approaching; where, though the brass and marble remain, yet the inscriptions are effaced by time, and the imagery moulders away. The pictures drawn in our minds are laid in fading colors; and, if not sometimes refreshed, vanish and disappear. How much the constitution of our bodies, and the make of our animal spirits, are concerned in this; and whether the temper of the brain makes this difference, that in some it retains the characters drawn on it like marble, in others like freestone, and in others little better than sand, I shall not here inquire, though it may seem probable that the constitution of the body does sometimes influence the memory; since we oftentimes find a disease quite strip the mind of all its ideas, and the flames of a fever in a few days calcine all those images to dust and confusion, which seemed to be as lasting as if graven in marble."38

This peculiar mixture of forgetting with our remembering is but one instance of our mind's selective activity. Selection is the very keel on which our mental ship is built. And in this case of memory its utility is obvious. If we remembered everything, we should on most occasions be as ill off as if we remembered nothing. It would take as long for us to recall a space of time as it took the original time to elapse, and we should never get ahead with our thinking. All recollected times undergo, accordingly, what M. Ribot calls foreshortening; and this foreshortening is due to the omission of an enormous number of the facts which filled them.

"As fast as the present enters into the past, our states of consciousness disappear and are obliterated. Passed in review at a few days' distance, nothing or little of them remains: most of them have made shipwreck in that great nonentity from which they never more will emerge, and they have carried with them the quantity of duration which was inherent in their being. This deficit of surviving conscious states is thus a deficit in the amount of represented time. The process of abridgment, of foreshortening, of which we have spoken, presupposes this deficit. If, in order to reach a distant reminiscence, we had to go through the entire series of terms which separate it from our present selves, memory would become impossible on account of the length of the operation. We thus reach the paradoxical result that one condition of remembering is that we should forget. Without totally forgetting a prodigious number of states of consciousness, and momentarily forgetting a large number, we could not remember at all. Oblivion, except in certain cases, is thus no malady of memory, but a condition of its health and its life."39

There are many irregularities in the process of forgetting which are as yet unaccounted for. A thing forgotten on one day will be remembered on the next. Something we have made the most strenuous efforts to recall, but all in vain, will, soon after we have given up the attempt, saunter into the mind, as Emerson somewhere says, as innocently as if it had never been sent for. Experiences of bygone date will revive after years of absolute oblivion, often as the result of some cerebral disease or accident which seems to develop latent paths of association, as the photographer's fluid develops the picture sleeping in the collodion film. The oftenest quoted of these cases is Coleridge's:

"In a Roman Catholic town in Germany, a young woman, who could neither read nor write, was seized with a fever, and was said by the priests to be possessed of a devil, because she was heard talking Latin, Greek, and Hebrew. Whole sheets of her ravings were written out, and found to consist of sentences intelligible in themselves, but having slight connection with each other. Of her Hebrew sayings, only a few could be traced to the Bible, and most seemed to be in the Rabbinical dialect. All trick was out of the question; the woman was a simple creature; there was no doubt as to the fever. It was long before any explanation, save that of demoniacal possession, could be obtained. At last the mystery was unveiled by a physician, who determined to trace back the girl's history, and who, after much trouble, discovered that at the age of nine she had been charitably taken by an old Protestant pastor, a great Hebrew scholar, in whose house she lived till his death. On further inquiry it appeared to have been the old man's custom for years to walk up and down a passage of his house into which the kitchen opened, and to read to himself with a loud voice out of his books. The books were ransacked, and among them were found several of the Greek and Latin Fathers, together with a collection of Rabbinical writings. In these works so many of the passages taken down at the young woman's bedside were identified that there could be no reasonable doubt as to their source."40

Hypnotic subjects as a rule forget all that has happened in their trance. But in a succeeding trance they will often remember the events of a past one. This is like what happens in those cases of 'double personality' in which no recollection of one of the lives is to be found in the other. We have already seen in an earlier chapter that the sensibility often differs from one of the alternate personalities to another, and we have heard M. Pierre Janet's theory that anæsthesias carry amnesias with them (see above, pp. 385 ff.). In certain cases this is evidently so; the throwing of certain functional brain-tracts out of gear with others, so as to dissociate their consciousness from that of the remaining brain, throws them out for both sensorial and ideational service. M. Janet proved in various ways that what his patients forgot when anæsthetic they remembered when the sensibility returned. For instance, he restored their tactile sense temporarily by means of electric currents, passes, etc., and then made them handle various objects, such as keys and pencils, or make particular movements, like the sign of the cross. The moment the anæsthesia returned they found it impossible to recollect the objects or the acts. 'They had had nothing in their hands, they had done nothing,' etc. The next day, however, sensibility being again restored by similar processes, they remembered perfectly the circumstance, and told what they had handled or had done.

All these pathological facts are showing us that the sphere of possible recollection may be wider than we think, and that in certain matters apparent oblivion is no proof against possible recall under other conditions. They give no countenance, however, to the extravagant opinion that nothing we experience can be absolutely forgotten. In real life, in spite of occasional surprises, most of what happens actually is forgotten. The only reasons for supposing that if the conditions were forthcoming everything would revive are of a transcendental sort. Sir Wm. Hamilton quotes and adopts them from the German writer Schmid. Knowledge being a 'spontaneous self-energy' on the part of the mind,

"this energy being once determined, it is natural that it should persist, until again annihilated by other causes. This [annihilation] would be the case, were the mind merely passive. . . . But the mental activity, the act of knowledge, of which I now speak, is more than this; it is an energy of the self-active power of a subject one and indivisible: consequently a part of the ego must be detached or annihilated, if a cognition once existent be again extinguished. Hence it is that the problem most difficult of solution is not, how a mental activity endures, but how it ever vanishes."41

Those whom such an argument persuades may be left happy with their belief. Other positive argument there is none, none certainly of a physiological sort.42

When memory begins to decay, proper names are what go first, and at all times proper names are harder to recollect than those of general properties and classes of things.

This seems due to the fact that common qualities and names have contracted an infinitely greater number of associations in our mind than the names of most of the persons whom we know. Their memory is better organized. Proper names as well organized as those of our family and friends are recollected as well as those of any other objects.43 'Organization' means numerous associations; and the more numerous the associations, the greater the number of paths of recall. For the same reason adjectives, conjunctions, prepositions, and the cardinal verbs, those words, in short, which form the grammatical framework of all our speech, are the very last to decay. Kussmaul44 makes the following acute remark on this subject:

"The concreter a conception is, the sooner is its name forgotten. This is because our ideas of persons and things are less strongly bound up with their names than with such abstractions as their business, their circumstances, their qualities. We easily can imagine persons and things without their names, the sensorial image of them being more important than that other symbolic image, their name. Abstract conceptions, on the other hand, are only acquired by means of the words which alone serve to confer stability upon them. This is why verbs, adjectives, pronouns, and still more adverbs, prepositions, and conjunctions are more intimately connected with our thinking than are substantives."

The disease called Aphasia, of which a little was said in Chapter II, has let in a flood of light on the phenomenon of Memory, by showing the number of ways in which the use of a given object, like a word, may be lost by the mind. We may lose our acoustic idea or our articulatory idea of it; neither without the other will give up proper command of the word. And if we have both, but have lost the paths of association between the brain-centres which support the two, we are in as bad a plight. 'Ataxic' and 'amnesic' aphasia, 'word-deafness,' and 'associative aphasia' are all practical losses of word-memory. We have thus, as M. Ribot says, not memory so much as memories.45 The visual, the tactile, the muscular, the auditory memory may all vary independently of each other in the same individual; and different individuals may have them developed in different degrees. As a rule, a man's memory is good in the departments in which his interest is strong; but those departments are apt to be those in which his discriminative sensibility is high. A man with a bad ear is not likely to have practically a good musical memory, or a purblind person to remember visual appearance well. In a later chapter we shall see illustrations of the differences in men's imagining power.46 It is obvious that the machinery of memory must be largely determined thereby.

Mr. Galton, in his work on English Men of Science,47 has given a very interesting collation of cases showing individual variations in the type of memory, where it is strong. Some have it verbal. Others have it good for facts and figures, others for form. Most say that what is to be remembered must first be rationally conceived and assimilated.48

There is an interesting fact connected with remembering, which, so far as I know, Mr. R. Verdon was the first writer expressly to call attention to. We can set our memory as it were to retain things for a certain time, and then let them depart.

"Individuals often remember clearly and well up to the time when they have to use their knowledge, and then, when it is no longer required, there follows a rapid and extensive decay of the traces. Many schoolboys forgot their lessons after they have said them, many barristers forgot details got up for a particular case. Thus a boy learns thirty lines of Homer, says them perfectly, and then forgets them so that he could not say five consecutive lines the next morning, and a barrister may be one week learned in the mysteries of making cog-wheels, but in the next he may be well acquainted with the anatomy of the ribs instead."49

The rationale of this fact is obscure; and the existence of it ought to make us feel how truly subtle are the nervous processes which memory involves. Mr. Verdon adds that

"When the use of a record is withdrawn, and attention withdrawn from it, and we think no more about it, we know that we experience a feeling of relief, and we may thus conclude that energy is in some way liberated. If the . . . attention is not withdrawn, so that we keep the record in mind, we know that this feeling of relief does not take place. . . . Also we are well aware, not only that after this feeling of relief takes place, the record does not seem so well conserved as before, but that we have real difficulty in attempting to remember it."

This shows that we are not as entirely unconscious of a topic as we think, during the time in which we seem to be merely retaining it subject to recall.

"Practically," says Mr. Verdon, "we sometimes keep a matter in hand not exactly by attending to it, but by keeping our attention referred to something connected with it from time to time. Translating this into the language of physiology, we mean that by referring attention to a part within, or closely connected with, the system of traces [paths] required to be remembered, we keep it well fed, so that the traces are preserved with the utmost delicacy."

This is perhaps as near as we can get to an explanation. Setting the mind to remember a thing involves a continual minimal irradiation of excitement into paths which lead thereto, involves the continued presence of the thing in the 'fringe' of our consciousness. Letting the thing go involves withdrawal of the irradiation, unconsciousness of the thing, and, after a time, obliteration of the paths. Fig46

A curious peculiarity of our memory is that things are impressed better by active than by passive repetition. I mean that in learning by heart (for example), when we almost know the piece, it pays better to wait and recollect by an effort from within, then to look at the book again. If we recover the words in the former way, we shall probably know them the next time; if in the latter way, we shall very likely need the book once more. The learning by heart means the formation of paths from a former set to a later set of cerebral word-processes: call 1 and 2 in the diagram the processes in question; then when we remember by inward effort, the path is formed by discharge from 1 to 2, just as it will afterwards be used. But when we excite 2 by the eye, although the path 1 -- 2 doubtless is then shot through also, the phenomenon which we are discussing shows that the direct discharge from 1 into 2, unaided by the eyes, ploughs the deeper and more permanent groove. There is, moreover, a greater amount of tension accumulated in the brain before the discharge from 1 to 2, when the latter takes place unaided by the eye. This is proved by the general feeling of strain in the effort to remember 2; and this also ought to make the discharge more violent and the path more deep. A similar reason doubtless accounts for the familiar fact that we remember our own theories, our own discoveries, combinations, inventions, in short whatever 'ideas' originate in our own brain, a thousand times better than exactly similar things which are communicated to us from without.

A word, in closing, about the metaphysics involved in remembering. According to the assumptions of this book, thoughts accompany the brain's workings, and those thoughts are cognitive of realities. The whole relation is one which we can only write down empirically, confessing that no glimmer of explanation of it is yet in sight. That brains should give rise to a knowing consciousness at all, this is the one mystery which returns, no matter of what sort the consciousness and of what sort the knowledge may be. Sensations, aware of mere qualities, involve the mystery as much as thoughts, aware of complex systems, involve it. To the platonizing tradition in philosophy, however, this is not so. Sensational consciousness is something quasi-material, hardly cognitive, which one need not much wonder at. Relating consciousness is quite the reverse, and the mystery of it is unspeakable. Professor Ladd, for example, in his usually excellent book,50 after well showing the matter-of-fact dependence of retention and reproduction on brain-paths, says:

"In the study of perception psycho-physics can do much towards a scientific explanation. It can tell what qualities of stimuli produce certain qualities of sensations; it can suggest a principle relating the quantity of the stimuli to the intensity of the sensation; it can investigate the laws under which, by combined action of various excitations, the sensations are combined [?] into presentations of sense; it can show how the time-relations of the sensations and percepts in consciousness correspond to the objective relations in time of the stimulations. But for that spiritual activity which actually puts together in consciousness the sensations, it cannot even suggest the beginning of a physical explanation. Moreover, no cerebral process can be conceived of, which -- in case it were known to exist -- could possibly be regarded as a fitting basis for this unifying actus of mind. Thus also, and even more emphatically, must we insist upon the complete inability of physiology to suggest an explanation for conscious memory, in so far as it is memory -- that is, in so far as it most imperatively calls for explanation. . . . The very essence of the act of memory consists in the ability to say: This after-image is the image of a percept I had a moment since; or this image of memory is the image of the percept I had at a certain time -- I do not remember precisely how long since. It would, then, be quite contrary to the facts to hold that, when an image of memory appears in consciousness, it is recognized as belonging to a particular original percept on account of its perceived resemblance to this percept. The original percept does not exist and will never be reproduced. Even more palpably false and absurd would it be to hold that any similarity of the impressions or processes in end organs or central organs explains the act of conscious memory. Consciousness knows nothing of such similarity; knows nothing even of the existence of nervous impressions and processes. Moreover, we could never know two impressions or processes that are separated in time to be similar, without involving the same inexplicable act of memory. It is a fact of consciousness on which all possibility of connected experience and of recorded and cumulative human knowledge is dependent that certain phases or products of consciousness appear with a claim to stand for (to represent)51 past experiences to which they are regarded as in some respect similar. It is this peculiar claim in consciousness which constitutes the essence of an act of memory; it is this which makes the memory wholly inexplicable as a mere persistence or recurrence of similar impressions. It is this which makes conscious memory a spiritual phenomenon, the explanation of which, as arising out of nervous processes and conditions, is not simply undiscovered in fact, but utterly incapable of approach by the imagination. When, then, we speak of a physical basis of memory, recognition must be made of the complete inability of science to suggest any physical process which can be conceived of as correlated with that peculiar and mysterious actus of the mind, connecting its present and its past, which constitutes the essence of memory."

This passage seems to me characteristic of the reigning half-way modes of thought. It puts the difficulties in the wrong places. At one moment it seems to admit with the cruder sensationalists that the material of our thoughts is independent sensations reproduced, and that the 'putting together' of these sensations would be knowledge, if it could only be brought about, the only mystery being as to the what 'actus' can bring it about. At another moment it seems to contend that even this sort of 'combining' would not be knowledge, because certain of the elements connected must 'claim to represent or stand for' past originals, which is incompatible with their being mere images revived. The result is various confused and scattered mysteries and unsatisfied intellectual desires. But why not 'pool' our mysteries into one great mystery, the mystery that brain-processes occasion knowledge at all? It is surely no different mystery to feel myself by means of one brain-process writing at this table now, and by means of a different brain-process a year hence to remember myself writing. All that psychology can do is to seek to determine what the several brain-processes are; and this, in a wretchedly imperfect way, is what such writings as the present chapter have begun to do. But of 'images reproduced,' and 'claiming to represent,' and 'put together by a unifying actus,' I have been silent, because such expressions either signify nothing, or they are only roundabout ways of simply saying that the past is known when certain brain-conditions are fulfilled, and it seems to me that the straightest and shortest way of saying that is the best.

For a history of opinion about Memory, and other bibliographic references, I must refer to the admirable little monograph on the subject by Mr. W. H. Burnham in the American Journal of Psychology, vols. I and II. Useful books are: D. Kay's Memory, What It Is, and How to Improve It (1888); and F. Fauth's Das Gedächtniss, Studie zu einer Pädagogik, etc., 1888.

1 L'Homme et 1'Intelligence, p. 32.

2 Professor Richet has therefore no right to say, as he does in another place (Revue Philosophique, XXI. 570): "Without memory no conscious sensation, without memory no consciousness." All he is entitled to say is: "Without memory no consciousness known outside of itself." Of the sort of consciousness that is an object for later states, and becomes as it were permanent, he gives a good example: "Who of us, alas! has not experienced a bitter and profound grief, the immense laceration caused by the death of some cherished fellow-being? Well, in these great griefs the present endures neither for a minute, for an hour, nor for a day, but for weeks and months. The memory of the cruel moment will not efface itself from consciousness. It disappears not, but remains living, present, coexisting with the multitude of other sensations which are juxtaposed in consciousness alongside of this one persistent emotion which is felt always in the present tense. A long time is needed ere we can attain to forgetting it, ere we can make it enter into the past. Hœret lateri letalis arundo." (Ibid 583.)

3 This is the primary positive after-image. According to Helmholtz, one third of a second is the most favorable length of exposure to the light for producing it. Longer exposure, complicated by subsequent admission of light to the eye, results in the ordinary negative and complementary after-images, with their changes, which may (if the original impression was brilliant and the fixation long) last for many minutes. Fechner gives the name of memory-after-images (Psychophysik, II 492) to the instantaneous positive effects, and distinguishes them from ordinary after images by the following characters: 1) Their originals must have been attended to only such parts of a compound original as have been attended to appearing. This is not the case in common visual after-images. 2) The strain of attention towards them is inward, as in ordinary remembering, not outward, as in observing a common after-image. 3) A short fixation of the original is better for the memory-after-image, a long one for the ordinary after-image. 4) The colors of the memory-after-image are never complementary of those of the original.

4 Hermann's Hdbch., II. 2. 282.

5 Rev. Philos., 562.

6 Richet says: "The present has a certain duration, a variable duration, sometimes a rather long one, which comprehends all the time occupied by the after-reverberation [retentissement, after-image] of a sensation. For example, if the reverberation of an electric shock within our nerves lasts ten minutes, for that electric shock there is a present of ten minutes. On the other hand, a feebler sensation will have a shorter present. But in every case, for a conscious sensation [I should say for a remembered sensation] to occur, there must be a present of a certain duration, of a few seconds at least." We have seen in the last chapter that it is hard to trace the backward limits of this immediately intuited duration, or specious present. The figures which M. Richet supposes appear to be considerably too large.

7 Cf. Fechner, Psychophysik, II. 499.

8 The primary after-image itself cannot be utilized if the stimulus is too brief. Mr. Cattell found (Psychologische Studien, III. p. 93 ff.) that the color of a light must fall upon the eye for a period varying from 0.00275 to 0.006 of a second, in order to be recognized for what it is. Letters of the alphabet and familiar words require from 0.00075 to 0.00175 sec.-- truly an interval extremely short. Some letters, E for example, are harder than others. In 1871 Helmholtz and Boxt had ascertained that when an impression was immediately followed by another, the latter quenched the former and prevented it from being known to later consciousness. The first stimulus was letters of the alphabet, the second a bright white disk. "With an interval of 0.0048 sec. between the two excitations [I copy here the abstract in Ladd's Physiological Psychology, p. 480], the disk appeared as scarcely a trace of a weak shimmer; with an interval of 0.0096 sec., letters appeared in the shimmer -- one or two which could
be partially recognized when the interval increased to 0.0144 sec. When the interval was made 0.0192 sec. the objects were a little more clearly discerned; at 0.0336 sec. four letters could be well recognized; at 0.0432 sec., five letters; and at 0.0528 sec. all the letters could be read." (Pflüger's Archiv, IV. 325 ff.)

9 When the past is recalled symbolically, or conceptually only, it is true that no such copy need be there. In no sort of conceptual knowledge is it requisite that definitely resembling images be there (cf. pp. 471 ff.). But as all conceptual knowledge stands for intuitive knowledge, and terminates therein, I abstract from this complication, and confine myself to those memories in which the past is directly imaged in the mind, or, as we say, intuitively known.

10 E.g. Spencer, Psychology, I. p. 448. How do the believers in the sufficiency of the 'image' formulate the cases where we remember that something did not happen -- that we did not wind our watch, did not lock the door, etc.? It is very hard to account for these memories of omission. The image of winding the watch is just as present to my mind now when I remember that I did not wind it as if I remembered that I did. It must be a difference in the mode of feeling the image which leads me to such different conclusions in the two cases. When I remember that I did wind it, I feel it grown together with its associates of past date and place. When I remember that I did not, it keeps aloof; the associates fuse with each other, but not with it. This sense of fusion, of the belonging together of things, is a most subtle relation; the sense of non-fusion is an equally subtle one. Both relations demand most complex mental processes to know them, processes quite different from that mere presence or absence of an image which does such service in the cruder books.

11 Psychologia Empirica, § 174.

12 Analysis, I. 330-1. Mill believed that the various things remembered, the self included, enter consciousness in the form of separate ideas, but so rapidly that they are 'all clustered into one.' "Ideas called up in close conjunction . . . assume, even when there is the greatest complexity, the appearance, not of many ideas, but of one" (vol. I. p. 123). This mythology does not impair the accuracy of his description of memory's object.

13 Compare, however, p. 251, Chapter IX.

14 Professor Bain adds, in a note to this passage of Mill's: "This process seems best expressed by laying down a law of Compound or Composite Association, under which a plurality of feeble links of connection may be a substitute for one powerful and self-sufficing link."

15 Analysis, chap. X.

16 H. Maudsley, The Physiology of Mind (London, 1876), p. 513.

17 The only fact which might plausibly be alleged against this view is the familiar one that we may feel the lapse of time in an experience so monotonous that its earlier portions can have no 'associates' different from its later ones. Sit with closed eyes, for example, and steadily pronounce some vowel-sound, thus, a--a--a--a--a-- . . . . thinking only of the sound. Nothing changes during the time occupied by the experiment, and yet at the end of it you know that its beginning was far away. I think, however, that a close attention to what happens during this experiment shows that it does not violate in the least the conditions of recall laid down in the text; and that if the moment to which we mentally hark back lie many seconds behind the present instant, it always has different associates by which we define its date. Thus it was when I had just breathed out, or in; or it was the 'first moment' of the performance, the one 'preceded by silence;' or it was 'one very close to that;' or it was 'one when we were looking forward instead of back, its now;' or it is simply represented by a number and conceived symbolically with no definite image of its date. It seems to me that I have no really intuitive discrimination of the different past moments after the experience has gone on some little time, but that back of the 'specious present' they all fuse into a single conception of the kind of thing that has been going on, with a more or less clear sense of the total time it has lasted, this latter being based on an automatic counting of the successive pulses of thought by which the process is from moment to moment recognized as being always the same. Within the few seconds which constitute the specious present there is an intuitive perception of the successive moments. But these moments, of which we have a primary memory-image, are not properly recalled from the past, our knowledge of them is in no way analogous to a memory properly so called. Cf. supra, p. 646.

18 On Intelligence, I. 258-9.

19 Not that mere native tenacity will make a man great. It must be coupled with great passions and great intellect besides. Imbeciles sometimes have extraordinary desultory memory. Drobisch describes (Empirische Psychol., p. 95) the case of a young man whom he examined. He had with difficulty been taught to read and speak. "But if two or three minutes were allowed him to peruse an octave page, he then could spell the single words out from his memory as well as if the book lay open before him. . . . That there was no deception I could test by means of a new Latin law-dissertation which had just come into my hands, which he never could have seen, and of which both subject and language were unknown to him. He read off [mentally] many lines, skipping about too, of the page which had been given him to see, no worse than if the experiment had been made with a child's story." Drobisch describes this case as if it were one of unusual persistence in the visual image ['primary memory,' vide supra, p. 643]. But he adds that the youth 'remembered his pages a long time.' In the Journal of Speculative Philosophy for Jan. 1871 (VI. 6) is an account by Mr. W. D Henkle (together with the stock classic examples of preternatural memory) of an almost blind Pennsylvania farmer who could remember the day of the week on which any date had fallen for forty-two years past, and also the kind of weather it was, and what he was doing on each of more than fifteen thousand days. Pity that such a magnificent faculty as this could not have found more worthy application!

What these cases show is that the mere organic retentiveness of a man need bear no definite relation to his other mental powers. Men of the highest general powers will often forget nothing, however insignificant. One of the most generally accomplished men I know has a memory of this sort. He never keeps written note of anything, yet is never at a loss for a fact which he has once heard. He remembers the old addresses of all his New York friends, living in numbered streets, addresses which they themselves have long since moved away from and forgotten. He says that he should probably recognize an individual fly, if he had seen him thirty years previous -- he is, by the way, an entomologist. As an instance of his desultory memory, he was introduced to a certain colonel at a club. The conversation fell upon the signs of age in man. The colonel challenged him to estimate his age. He looked at him, and gave the exact day of his birth, to the wonder of all. But the secret of this accuracy was that, having picked up some days previously an army-register, he had idly turned over its list of names, with dates of birth, graduation, promotions, etc., attached, and when the colonel's name was mentioned to him at the club, these figures, on which he had not bestowed a moment's thought, involuntarily surged up in his mind. Such a memory is of course a priceless boon.

20 Cf. Ebbinghaus: Ueber das Gedächtniss (1885), pp. 67, 45. One may hear a person say: "I have a very poor memory, because I was never systematically made to learn poetry at school."

21 How to Strengthen the Memory; or, The Natural and Scientific Methods of Never Forgetting. By M. H. Holbrook, M.D. New York (no date).

22 Page 39.

23 Op. cit. p. 100.

24 In order to test the opinion so confidently expressed in the text, I have tried to see whether a certain amount of daily training in learning poetry by heart will shorten the time it takes to learn an entirely different kind of poetry. During eight successive days I learned 158 lines of Victor Hugo's 'Satyr.' The total number of minutes required for this was 131 5/6 -- it should be said that I had learned nothing by heart for many years. I then, working for twenty-odd minutes daily, learned the entire first book of Paradise Lost, occupying 38 days in the process. After this training I went back to Victor Hugo's poem, and found that 158 additional lines (divided exactly as on the former occasion) took me 151 1/2 minutes. In other words, I committed my Victor Hugo to memory before the training at the rate of a line in 50 seconds, after the training at the rate of a line in 57 seconds, just the opposite result from that which the popular view would lead one to expect. But as I was peceptibly tagged with other work at the time of the second batch of Victor Hugo, I thought that might explain the retardation; so I persuaded several other persons to repeat the test.

Dr. W. H. Burnham learned 16 lines of In Memoriam for 8 days; time, 14-17 minutes -- daily average 14 3/4. He then trained himself on Schiller's translation of the second book of the Æneid into German, 16 lines daily for 26 consecutive days. On returning to the same quantity of In Memoriam again, he found his maximum time 20 minutes, minimum 10, average 14 27/48. As he feared the outer conditions might not have been as favorable this time as the first, he waited a few days and got conditions as near as possible identical. The result was maximum time 8 minutes; minimum 19 1/2; average 14 3/48.

Mr. E. S. Drown tested himself on Virgil for 16 days, then again for 16 days, after training himself on Scott. Average time before training, 13 minutes 26 seconds; after training, 12 minutes 16 seconds. [Sixteen days is too long for the test, it gives time for training on the test-verse.]

Mr. C. H. Baldwin took 10 lines for l5 days as his test, trained himself on 450 lines 'of an entirely different verse,' and then took 15 days more of the former verse 10 lines a day. Average result: 3 minutes 41 seconds before, 3 minutes 2 seconds after, training. [Same criticism as before.]

Mr. E. A. Pease tested himself on Idyls of the King, and trained himself on Paradise Lost. Average result of 6 days each time: 14 minutes 34 seconds before, 14 minutes 55 seconds after, training. Mr. Burnham having suggested that to eliminate facilitating effect entirely from the training verses one ought to test one's self à là Ebbinghaus on series of nonsense-syllables, having no analogy whatever with any system of expressive verses. I induced two of my students to perform that experiment also. The record is unfortunately lost; but the result was a very considerable shortening of the average time of the second series of nonsense-syllables, learned after training. This seems to me, however, more to show the effects of rapid habituation to the nonsense-verses themselves than those of the poetry used between them. But I mean to prosecute the experiments farther, and will report in another place.

One of my students having quoted a clergyman of his acquaintance who had marvellously improved by practice his power of learning his sermons by heart, I wrote to the gentleman for corroboration. I append his reply, which shows that the increased facility is due rather to a change in his methods of learning than to his native retentiveness having grown by exercise: "As for memory, mine has improved year by year, except when in ill-health, like a gymnast's muscle. Before twenty it took three or four days to commit an hour-long sermon; after twenty, two days, one day, half a day, and now one slow analytic, very attentive or adhesive reading does it. But memory seems to me the most physical of intellectual powers. Bodily ease and freshness have much to do with it. Then there is a great difference of facility in method. I used to commit sentence by sentence. Now I take the idea of the whole, then its leading divisions, then its subdivisions, then its sentences."

25 E. Pick: Memory and its Doctors (1888), p. 7.

26 This system is carried out in great detail in a book called 'Memory Training,' by Wm. L. Evans (1889).

27 Paulhan, L'Activité mental, et les É1éments de 1'Esprit (1889), p. 70.

28 On Intelligence, I. 77-82.

29 Psychology, § 201.

30 Professor Höffding considers that the absence of contiguous associates distinctly thought-of is a proof that associative processes are not concerned in these cases of instantaneous recognition where we get a strong sense of familiarity with the object, but no recall of previous time or place. His theory of what happens is that the object before us, A, comes with a sense of familiarity whenever it awakens a slumbering image, a, of its own past self, whilst without this image it seems unfamiliar. The quality of familiarity is due to the coalescence of the two similar processes A + a in the brain (Psychologie, p. 188; Vierteljsch. f. wiss. Phil., XIII. 432 1889). This explanation is a very tempting one where the phenomenon of recognition is reduced to its simplest terms. Experiments have been performed in Wundt's laboratory (by Messrs. Wolfe, see below, p. 679, and Lehmann (Philosophische Studien,v. 96)), in which a person had to tell out of several closely resembling sensible impressions (sounds, tints of color) presented, which of them was the same with one presented a moment before. And it does seem here as if the fading process in the just-excited tract must combine with the process of the new impression to give to the latter a peculiar subjective tinge which should separate it from the impressions which the other objects give. But recognition of this immediate sort is beyond our power after a very short time has intervened. A couple of minutes' interval is generally fatal to it; so that it is impossible to conceive that our frequent instantaneous recognition of a face, e.g., as having been met before, takes place by any such simple process. Where we associate a head of classification with the object, the time-interval has much less effect. Dr. Lehmann could identify shades of gray much more successfully and permanently after mentally attaching names or numbers to them. Here it is the recall of the contiguous associate, the number or name, which brings about the recognition. Where an experience is complex, each element of the total object has had the other elements for its past contiguous associates. Each element thus tends to revive the other elements from within, at the same time that the outward object is making them revive from without. We have thus, whenever we meet a familiar object, that sense of expectation gratified which is so large a factor in our æsthetic emotions; and even were there no 'fringe of tendency' toward the arousal of extrinsic associates (which there certainly always is), still this intrinsic play of mutual association among the parts would give a character of ease to familiar percepts which would make of them a distinct subjective class. A process fills its old bed in a different way from that in which it makes a new bed. One can appeal to introspection for proof. When, for example, I go into a slaughter-house into which I once went years ago, and the horrid din of the screaming hogs strikes me with the overpowering sense of identification, when the blood-stained face of the 'sticker,' whom I had long ceased to think of, is immediately recognized as the face that struck me so before; when the dingy and reddened woodwork, the purple-flowing floor, the smell, the emotion of disgust, and all the details, in a word, forthwith re-establish themselves as familiar occupants of my mind; the extraneous associates of the past time are anything but prominent. Again, in trying to think of an engraving, say the portrait of Rajah Brooke prefixed to his biography, I can do so only partially; but when I take down the book and, looking at the actual face, am smitten with the intimate sense of its sameness with the one I was striving to resuscitate, -- where in the experience is the element of extrinsic association? In both these cases it surely feels as if the moment when the sense of recall is most vivid were also the moment when all extraneous associates were most suppressed. The butcher's face recalls the former walls of the shambles; their thought recalls the groaning beasts, and they the face again, just as I now experience them, with no different past ingredient. In like manner the peculiar deepening of my consciousness of the Rajah's physiognomy at the moment when I open the book and say "Ah! that's the very face!" is so intense as to banish from my mind all collateral circumstances, whether of the present or of former experiences. But here it is the nose preparing tracts for the eye, the eye preparing them for the mouth, the mouth preparing them for the nose again, all these processes involving paths of contiguous association, as defended in the text. I cannot agree, therefore, with Prof. Höffding, in spite of my respect for him as a psychologist, that the phenomenon of instantaneous recognition is only explicable through the recall and comparison of the thing with its own past image. Nor can I see in the facts in question any additional ground for reinstating the general notion which we have already rejected (supra, p. 592) that a 'sensation' is ever received into the mind by an 'image' of its own past self. It is received by contiguous associates; or if they form too faint a fringe, its neural currents run into a bed which is still 'warm' from just-previous currents, and which consequently feel different from currents whose bed is cold. I agree, however, with Höffding that Dr. Lehmann's experiments (many of them) do not seem to prove the point which he seeks to establish. Lehmann, indeed, seems himself to believe that we recognize a sensation A by comparing it with its own past image a (loc. cit. p. 114), in which opinion I altogether fail to concur.

31 Duality of the Mind, p. 84. The same thesis is defended by the late Mr. R. H. Proctor, who gives some cases rather hard to reconcile with my own proposed explanation, in 'Knowledge' for Nov. 8, 1884. See also Ribot, Maladies de la Mémoire, p. 149 ff.

32 Zeitschr. f. Völkerpsychologie u. s. w., Bd. v. p. 146.

33 Ueber das Gedächtniss, experimentelle Untersuchungen (1885), p. 64.

34 Ibid. § 23.

35 Op. cit., p. 103.

36 All the inferences for which we can give no articulate reasons exemplify this law. In the chapter on Perception we shall have innumerable examples of it. A good pathological illustration of it is given in the curious observations of M. Binet on certain hysterical subjects, with anæsthetic hands, who saw what was done with their hands as an independent vision but did not feel it. The hand being hidden by a screen, the patient was ordered to look at another screen and to tell of any visual image which might project itself thereon. Numbers would then come, corresponding to the number of times the insensible member was raised, touched, etc. Colored lines and figures would come, corresponding to similar ones traced on the palm; the hand itself, or its fingers, would come when manipulated; and, finally, objects placed in it would come; but on the hand itself nothing could ever be felt. The whole phenomenon shows how an idea which remains itself below the threshold of a certain conscious self may occasion associative effects therein. The skin-sensations, unfelt by the patient's primary consciousness, awaken, nevertheless, their usual visual associates therein.

37 I copy from the abstract of Wolfe's paper in 'Science' for Nov. 19, 1886. The original is in Psychologische Studien, III. 534 ff.

38 Essay conc. Human Understanding, II. X. 5.

39 Th. Ribot, Les Maladies de la Mémoire, p. 46.

40 Biographia Literaria, ed. 1847, I. 117(quoted in Carpenter's Mental Physiology, chapter X, which see for a number of other cases, all unfortunately deficient, like this one, in the evidence of erect verification which 'psychical research 'demands). Compare also Th. Ribot, Diseases of Memory. chap. IV. The knowledge of foreign words, etc., reported in trance-mediums, etc., may perhaps often be explained by exaltation of memory. An hystero-epileptic girl, whose case I quoted in Proc. of Am. Soc. for Psychical Research, automatically writes an 'Ingoldsby Legend ' in several cantos, which her parents say she 'had never read.' Of course she must have read or heard it, but perhaps never learned it. Of some macaronic Latin-English verses about a sea-serpent which her hand also wrote unconsciously, I have vainly sought the original (see Proc., etc., p. 553).

41 Lectures on Metaph., II 212.

42 Cf. on this point J. Delbœuf, Le Sommeil et les Rêves (1885), p 119 ff., R. Verdon, Forgetfulness, in Mind, II. 437.

43 Cf. A. Maury, Le Sommeil et les Rêves, p. 442.

44 Störungen der Sprache, quoted by Ribot, Les Maladies de la M., p. 133.

45 Op. cit. chap. III.

46 "Those who have a good memory for figures are in general those who know best how to handle them, that is, those who are most familiar with their relations to each other and to things." (A. Maury, Le Sommeil et les Rêves, p. 443.)

47 Pp. 107-121.

48 For other examples see Hamilton's Lectures, II. 219, and A. Huber: Das Gedächtniss, p. 36 ff.

49 Mind, II. 449.

50 Physiological Psychology, pt. II. chap. X. § 23.

51 Why not say 'know'? -- W. J.

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