Chapter IX

, pp. 265-6.

* * * * *

_The study of Aphasia_ (see Vol. I, p. 54) _has of late years shown how unexpectedly great are the differences between individuals in respect of imagination._ And at the same time the discrepancies between lesion and symptom in different cases of the disease have been largely cleared up. In some individuals the habitual 'thought-stuff,' if one may so call it, is visual; in others it is auditory, articulatory, or motor; in most, perhaps, it is evenly mixed. The same local cerebral injury must needs work different practical results in persons who differ in this way. In one it will throw a much-used brain-tract out of gear; in the other it may affect an unimportant region. A particularly instructive case was published by Charcot in 1883.[59] The patient was

Mr. X., a merchant, born in Vienna, highly educated, master of German, Spanish, French, Greek, and Latin. Up to the beginning of the malady which took him to Professor Charcot, he read Homer at sight. He could, starting from any verse out of the first book of the Iliad, repeat the following verses without hesitating, by heart. Virgil and Horace were familiar. He also knew enough of modern Greek for business purposes. Up to within a year (from the time Charcot saw him) he enjoyed an exceptional _visual_ memory. He no sooner thought of persons or things, but features, forms, and colors arose with the same clearness, sharpness, and accuracy as if the objects stood before him. When he tried to recall a fact or a figure in his voluminous polyglot correspondence, the letters themselves appeared before him with their entire content, irregularities, erasures and all. At school he recited from a mentally seen page which he read off line by line and letter by letter. In making computations, he ran his mental eye down imaginary columns of figures, and performed in this way the most varied operations of arithmetic. He could never think of a passage in a play without the entire scene, stage, actors, and audience appearing to him. He had been a great traveller. Being a good draughtsman, he used to sketch views which pleased him; and his memory always brought back the entire landscape exactly. If he thought of a conversation, a saying, an engagement, the place, the people, the entire scene rose before his mind.

His _auditory memory_ was always deficient, or at least secondary. He had no taste for music.

A year and a half previous to examination, after business-anxieties, loss of sleep, appetite, etc., he noticed suddenly one day an extraordinary change in himself. After complete confusion, there came a violent contrast between his old and his new state. Everything about him seemed so new and foreign that at first he thought he must be going mad. He was nervous and irritable. Although he saw all things distinct, he had entirely lost his memory for forms and colors. On ascertaining this, he became reassured as to his sanity. He soon discovered that he could carry on his affairs by using his memory in an altogether new way. He can now describe clearly the difference between his two conditions.

Every time he returns to A., from which place business often calls him, he seems to himself as if entering a strange city. He views the monuments, houses, and streets with the same surprise as if he saw them for the first time. Gradually, however, his memory returns, and he finds himself at home again. When asked to describe the principal public place of the town, he answered, "I know that it is there, but it is impossible to imagine it, and I can tell you nothing about it." He has often drawn the port of A. To-day he vainly tries to trace its principal outlines. Asked to draw a minaret, he reflects, says it is a square tower, and draws, rudely, four lines, one for ground, one for top, and two for sides. Asked to draw an arcade, he says, "I remember that it contains semi-circular arches, and that two of them meeting at an angle make a vault, but how it _looks_ I am absolutely unable to imagine." The profile of a man which he drew by request was as if drawn by a little child; and yet he confessed that he had been helped to draw it by looking at the bystanders. Similarly he drew a shapeless scribble for a tree.

He can no more remember his wife's and children's faces than he can remember the port of A. Even after being with them some time they seem unusual to him. He forgets his own face, and once spoke to his image in a mirror, taking it for a stranger. He complains of his loss of feeling for colors. "My wife has black hair, this I know; but I can no more recall its color than I can her person and features." This visual amnesia extends to dating objects from his childhood's years--paternal mansion, etc., forgotten.

No other disturbances but this loss of visual images. Now when he seeks something in his correspondence, he must rummage among the letters like other men, until he meets the passage. He can recall only the first few verses of the Iliad, and must _grope_ to read Homer, Virgil, and Horace. Figures which he adds he must now whisper to himself. He realises clearly that he must help his memory out with auditory images, which he does with effort. _The words and expressions which he recalls seem now to echo in his ear, an altogether novel sensation for him._ If he wishes to learn by heart anything, a series of phrases for example, he must _read them several times aloud_, so as to impress his ear. When later he repeats the thing in question, the sensation of inward hearing which precedes articulation rises up in his mind. This feeling was formerly unknown to him. He speaks French fluently; but affirms that he can no longer think in French; but must get his French words by translating them from Spanish or German, the languages of his childhood. He dreams no more in visual terms, but only in words, usually Spanish words. A certain degree of verbal blindness affects him--he is troubled by the Greek alphabet, etc.[60]

If this patient had possessed the auditory type of imagination from the start, it is evident that the injury, whatever it was, to his centres for optical imagination, would have affected his practical life much less profoundly.

"_The auditory type_," says M. A. Binet,[61] "_appears to be rarer than the visual._ Persons of this type imagine what they think of in the language of sound. In order to remember a lesson they impress upon their mind, not the look of the page, but the sound of the words. They reason, as well as remember, by ear. In performing a mental addition they repeat verbally the names of the figures, and add, as it were, the sounds, without any thought of the graphic signs. Imagination also takes the auditory form. 'When I write a scene,' said Legouvé to Scribe, 'I _hear_; but you _see_. In each phrase which I write, the voice of the personage who speaks strikes my ear. _Vous, qui êtes le théâtre même_, your actors walk, gesticulate before your eyes; I am a _listener_, you a _spectator_.'--'Nothing more true,' said Scribe; 'do you know where I am when I write a piece? In the middle of the parterre.' It is clear that the _pure audile_, seeking to develop only a single one of his faculties, may, like the pure visualizer, perform astounding feats of memory--Mozart, for example, noting from memory the _Miserere_ of the Sistine Chapel after two hearings; the deaf Beethoven, composing and inwardly repeating his enormous symphonies. On the other hand, the man of auditory type, like the visual, is exposed to serious dangers; for if he lose his auditory images, he is without resource and breaks down completely.

"It is possible that persons with hallucinations of hearing, and individuals afflicted with the mania that they are victims of persecution, may all belong to the auditory type; and that the predominance of a certain kind of imagination may predispose to a certain order of hallucinations, and perhaps of delirium.

* * * * *

"The _motor type_ remains--perhaps the most interesting of all, and certainly the one of which least is known. Persons who belong to this type [_les moteurs_, in French, _motiles_, as Mr. Galton proposes to call them in English] make use, in memory, reasoning, and all their intellectual operations, of images derived from movement. In order to understand this important point, it is enough to remember that 'all our perceptions, and in particular the important ones, those of sight and touch, contain as integral elements the movements of our eyes and limbs; and that, if movement is ever an essential factor in our really seeing an object, it must be an equally essential factor when we see the same object in imagination' (Ribot).[62] For example, the complex impression of a ball, which is there, in our hand, is the resultant of optical impressions of touch, of muscular adjustments of the eye, of the movements of our fingers, and of the muscular sensations which these yield. When we imagine the ball, its idea must include the images of these muscular sensations, just as it includes those of the retinal and epidermal sensations. They form so many _motor images_. If they were not earlier recognized to exist, that is because our knowledge of the muscular sense is relatively so recent. In older psychologies it never was mentioned, the number of senses being restricted to five.

"There are persons who remember a drawing better when they have followed its outlines with their finger. Lecoq de Boisbaudran used this means in his artistic teaching, in order to accustom his pupils to draw from memory. He made them follow the outlines of figures with a pencil held in the air, forcing them thus to associate muscular with visual memory. Galton quotes a curious corroborative fact. Colonel Moncrieff often observed in North America young Indians who, visiting occasionally his quarters, interested themselves greatly in the engravings which were shown them. One of them followed with care with the point of his knife the outline of a drawing in the Illustrated London News, saying that this was to enable him to carve it out the better on his return home. In this ease the motor images were to reinforce the visual ones. The young savage was a _motor_....[63] When one's motor images are destroyed, one loses one's remembrance of movements, and sometimes, more curiously still, one loses the power of executing them. Pathology gives us examples in motor aphasia, agraphia, etc. Take the case of agraphia. An educated man, knowing how to write, suddenly loses this power, as a result of cerebral injury. His hand and arm are in no way paralytic, yet he cannot write. Whence this loss of power? He tells us himself: he no longer knows how. He has forgotten how to set about it to trace the letters, he has lost the memory of the movements to be executed, he has no longer the motor images which, when formerly he wrote, directed his hand.... Other patients, affected with word-blindness, resort to these motor images precisely to make amends for their other deficiency.... An individual affected in this way cannot read letters which are placed before his eyes, even although his sight be good enough for the purpose. This loss of the power of reading by sight may, at a certain time, be the only trouble the patient has. Individuals thus mutilated succeed in reading by an ingenious roundabout way which they often discover themselves: it is enough that they should trace the letters with their finger to understand their sense. What happens in such a case? How can the hand supply the place of the eye? The motor image gives the key to the problem. If the patient can read, so to speak, with his fingers, it is because in tracing the letters he gives himself a certain number of muscular impressions which are those of writing. In one word, the patient reads by writing (Charcot): the feeling of the graphic movements suggests the sense of what is being written as well as sight would."[64]

The imagination of a blind-deaf mute like Laura Bridgman must be confined entirely to tactile and motor material. _All blind persons must belong to the 'tactile' and 'motile' types_ of the French authors. When the young man whose cataracts were removed by Dr. Franz was shown different geometric figures, he said he "had not been able to form from them the idea of a square and a disk until he perceived a sensation of what he saw in the points of his fingers, as if he really touched the objects."[65]

Professor Stricker of Vienna, who seems to have the motile form of imagination developed in unusual strength, has given a very careful analysis of his own case in a couple of monographs with which all students should become familiar.[66] His recollections both of his own movements and of those of other things are accompanied invariably by distinct muscular feelings in those parts of his body which would naturally be used in effecting or in following the movement. In thinking of a soldier marching, for example, it is as if he were helping the image to march by marching himself in his rear. And if he suppresses this sympathetic feeling in his own legs, and concentrates all his attention on the imagined soldier, the latter becomes, as it were, paralyzed. In general his imagined movements, of whatsoever objects, seem paralyzed the moment no feelings of movement either in his own eyes or in his own limbs accompany them.[67] The movements of articulate speech play a predominant part in his mental life.

"When after my experimental work I proceed to its description, as a rule I reproduce in the first instance only words, which I had already associated with the perception of the various details of the observation whilst the latter was going on. For speech plays in all my observing so important a part that I ordinarily clothe phenomena in words as fast as I observe them."[68]

Most persons, on being asked _in what sort of terms they imagine words_, will say 'in terms of hearing.' It is not until their attention is expressly drawn to the point that they find it difficult to say whether auditory images or motor images connected with the organs of articulation predominate. A good way of bringing the difficulty to consciousness is that proposed by Stricker: Partly open your mouth and then imagine any word with labials or dentals in it, such as 'bubble, 'toddle.' Is your image under these conditions distinct? To most people the image is at first 'thick,' as the sound of the word would be if they tried to pronounce it with the lips parted. Many can never imagine the words clearly with the mouth open; others succeed after a few preliminary trials. The experiment proves how dependent our verbal imagination is on actual feelings in lips, tongue, throat, larynx, etc.

"When we recall the impression of a word or sentence, if we do not speak it out, we feel the twitter of the organs just about to come to that point. The articulating parts--the larynx, the tongue, the lips--are all sensibly excited; a _suppressed articulation is in fact the material of our recollection_, the intellectual manifestation, the _idea_ of speech."[69]

The open mouth in Stricker's experiment not only prevents actual articulation of the labials, but our feeling of its openness keeps us from imagining their articulation, just as a sensation of glaring light will keep us from strongly imagining darkness. In persons whose auditory imagination is weak, the articulatory image seems to constitute the whole material for verbal thought. Professor Stricker says that in his own case no auditory image enters into the words of which he thinks.[70] Like most psychologists, however, he makes of his personal peculiarities a rule, and says that verbal thinking is normally and universally an exclusively motor representation. _I_ certainly get auditory images, both of vowels and of consonants, in addition to the articulatory images or feelings on which this author lays such stress. And I find that numbers of my students, after repeating his experiments, come to this conclusion. There is _at first_ a difficulty due to the open mouth. That, however, soon vanishes, as does also the difficulty of thinking of one vowel whilst continuously sounding another. What probably remains true, however, is that most men have a less auditory and a more articulatory verbal imagination than they are apt to be aware of. Professor Stricker himself has acoustic images, and can imagine the sounds of musical instruments, and the peculiar voice of a friend. A statistical inquiry on a large scale, into the variations of acoustic, tactile, and motor imagination, would probably bear less fruit than Galton's inquiry into visual images. A few monographs by competent observers, like Stricker, about their own peculiarities, would give much more valuable information about the diversities which prevail.[71]

_Touch-images_ are very strong in some people. The most vivid touch-images come when we ourselves barely escape local injury, or when we see another injured. The place may then actually tingle with the imaginary sensation--perhaps not altogether imaginary, since goose-flesh, paling or reddening, and other evidences of actual muscular contraction in the spot may result.

"An educated man," says a writer who must always be quoted when it is question of the powers of imagination,[72] "told me once that on entering his house one day he received a shock from crushing the finger of one of his little children in the door. At the moment of his fright he felt a violent pain in the corresponding finger of his own body, and this pain abode with him three days."

The same author makes the following discrimination, which probably most men could verify:

"On the skin I easily succeed in bringing out suggested sensations wherever I will. But because it is necessary to protract the mental effort I can only awaken such sensations as are in their nature prolonged, as warmth, cold, pressure. Fleeting sensations, as those of a prick, a cut, a blow, etc., I am unable to call up, because I cannot imagine them _ex abrupto_ with the requisite intensity. The sensations of the former order I can excite upon any part of the skin; and they may become so lively that, whether I will or not, I have to pass my hand over the place just as if it were a real impression on the skin."[73]

_Meyer's account of his own visual images_ is very interesting; and with it we may close our survey of differences between the normal powers of imagining in different individuals.

"With much practice," he says, "I have succeeded in making it possible for me to call up subjective visual sensations at will. I tried all my experiments by day or at night with closed eyes. At first it was very difficult. In the first experiments which succeeded the whole picture was luminous, the shadows being given in a somewhat less strong bluish light. In later experiments I saw the objects dark, with bright outlines, or rather I saw outline drawings of them, bright on a dark ground. I can compare these drawings less to chalk drawings on a blackboard than to drawings made with phosphorus on a dark wall at night, though the phosphorus would show luminous vapors which were absent from my lines. If I wished, for example, to see a face, without intending that of a particular person, I saw the outline of a profile against the dark background. When I tried to repeat an experiment of the elder Darwin I saw only the edges of the die as bright lines on a dark ground. Sometimes, however, I saw the die really white and its edges black; it was then on a paler ground. I could soon at will change between a white die with black borders on a light field, and a black die with white borders on a dark field; and I can do this at any moment now. After long practice ... these experiments succeeded better still. I can now call before my eyes almost any object which I please, as a subjective appearance, and this in its own natural color and illumination. I see them almost always on a more or less light or dark, mostly dimly changeable ground. Even known faces I can see quite sharp, with the true color of hair and cheeks. It is odd that I see these faces mostly in profile, whereas those described [in the previous extract] were all full-face. Here are some of the final results of these experiments:

"1) Some time after the pictures have arisen they vanish or change into others, without my being able to prevent it.

"2) When the color does not integrally belong to the object, I cannot always control it. A face, e.g., never seems to me blue, but always in its natural color; a red cloth, on the other hand, I can sometimes change to a blue one.

"3) I have sometimes succeeded in seeing pure colors without objects; they then fill the entire field of view.

"4) I often fail to see objects which are not known to me, mere fictions of my fancy, and instead of them there will appear familiar objects of a similar sort; for instance, I once tried to see a brass sword-hilt with a brass guard, instead of which the more familiar picture of a rapier-guard appeared.

"5) Most of these subjective appearances, especially when they were bright, left after-images behind them when the eyes were quickly opened during their presence. For example, I thought of a silver stirrup, and after I had looked at it a while I opened my eyes and for a long while afterwards saw its after-image.

"These experiments succeeded best when I lay quietly on my back and closed my eyes. I could bear no noise about me, as this kept the vision from attaining the requisite intensity. The experiments succeed with me now so easily that I am surprised they did not do so at first, and I feel as though they ought to succeed with everyone. The important point in them is to get the image sufficiently intense by the exclusive direction of the attention upon it, and by the removal of all disturbing impressions."[74]

_The negative after-images which succeeded upon Meyer's imagination when he opened his eyes_ are a highly interesting, though rare, phenomenon. So far as I know there is only one other published report of a similar experience.[75] It would seem that in such a case the neural process corresponding to the imagination must be the entire tract concerned in the actual sensation, even down as far as the retina. This leads to a new question to which we may now turn--of what is

THE NEURAL PROCESS WHICH UNDERLIES IMAGINATION?

The commonly-received idea is that it is only a milder degree of the same process which took place when the thing now imagined was sensibly perceived. Professor Bain writes:

"Since a sensation in the first instance diffuses nerve-currents through the interior of the brain outwards to the organs of expression and movement,--the persistence of that sensation, after the outward exciting cause is withdrawn, can be but a continuance of the same diffusive currents, perhaps less intense, but not otherwise different. The shock remaining in the ear and brain, after the sound of thunder, must pass through the same circles, and operate in the same way as during the actual sound. We can have no reason for believing that, in this self-sustaining condition, the impression changes its seat, or passes into some new circles that have the special property of retaining it. Every part actuated _after_ the shock must have been actuated _by_ the shock, only more powerfully. With this single difference of intensity, the mode of existence of a sensation existing after the fact is essentially the same as its mode of existence during the fact.... Now if this be the case with impressions _persisting_ when the cause has ceased, what view are we to adopt concerning impressions _reproduced_ by mental causes alone, or without the aid of the original, as in ordinary recollection? What is the manner of occupation of the brain with a resuscitated feeling of resistance, a smell or a sound? There is only one answer that seems admissable. _The renewed feeling occupies the very same parts, and in the same manner, as the original feeling, and no other parts, nor in any other assignable manner._ I imagine that if our present knowledge of the brain had been present to the earliest speculators, this is the only hypothesis that would have occurred to them. For where should a past feeling be embodied, if not in the same organs as the feeling when present? It is only in this way that its identity can be preserved; a feeling differently embodied would be a different feeling."[76]

It is not plain from Professor Bain's text whether by the 'same parts' he means only the same parts _inside the brain_, or the same _peripheral_ parts also, as those occupied by the original feeling. The examples which he himself proceeds to give are almost all cases of imagination of _movement_, in which the peripheral organs are indeed affected, for actual movements of a weak sort are found to accompany the idea. This is what we should expect. All currents tend to run forward in the brain and discharge into the muscular system; and the idea of a movement tends to do this with peculiar facility. But the question remains: Do currents run _backward_, so that if the optical centres (for example) are excited by 'association' and a visual object is imagined, a current runs _down to the retina_ also, and excites that sympathetically with the higher tracts? In other words, _can peripheral sense-organs be excited from above, or only from without? Are they excited in imagination?_ Professor Bain's instances are almost silent as to this point. All he says is this:

"We might think of a blow on the hand until the skin were actually irritated and inflamed. The attention very much directed to any part of the body, as the great toe, for instance, is apt to produce a distinct feeling in the part, which we account for only by supposing a revived nerve-current to flow there, making a sort of false sensation, an influence from within mimicking the influences from without in sensation proper.--(See the writings of Mr. Braid, of Manchester, on Hypnotism, etc.)"

If I may judge from my own experience, all feelings of this sort are consecutive upon motor currents invading the skin and producing contraction of the muscles there, the muscles whose contraction gives 'goose-flesh' when it takes place on an extensive scale. I never get a _feeling_ in the skin, however strongly I _imagine_ it, until some actual change in the condition of the skin itself has occurred. The truth seems to be that the cases where peripheral sense-organs are directly excited in consequence of imagination are exceptional rarities, if they exist at all. _In common cases of imagination it would seem more natural to suppose that the seat of the process is purely cerebral, and that the sense-organ is left out._ Reasons for such a conclusion would be briefly these:

1) In imagination the _starting-point_ of the process must be in the brain. Now we know that currents usually flow one way in the nervous system; and for the peripheral sense-organs to be excited in these cases, the current would have to flow backward.

2) There is between imagined objects and felt objects a difference of conscious quality which may be called almost absolute. It is hardly possible to confound the liveliest image of fancy with the weakest real sensation. The felt object has a plastic reality and outwardness which the imagined object wholly lacks. Moreover, as Fechner says, in imagination the attention feels as if drawn backwards to the brain; in sensation (even of after-images) it is directed forward towards the sense-organ.[77] The difference between the two processes feels like one of kind, and not like a mere 'more' or 'less' of the same.[78] If a sensation of sound were only a strong imagination, and an imagination a weak sensation, there ought to be a border-line of experience where we never could tell whether we were hearing a weak sound or imagining a strong one. In comparing a present sensation felt with a past one imagined, it will be remembered that we often judge the imagined one to _have been the stronger_ (see above, Vol. I p. 500, note). This is inexplicable if the imagination be simply a weaker excitement of the sensational process.

To these reasons the following objections may be made:

To 1): The current demonstrably _does_ flow backward down the optic nerve in Meyer's and Féré's negative after-image. Therefore it _can_ flow backward; therefore it _may_ flow backward in some, however slight, degree, in all imagination.[79]

To 2): The difference alleged is not absolute, and sensation and imagination _are_ hard to discriminate where the sensation is so weak as to be just perceptible. At night hearing a very faint striking of the hour by a far-off clock, our imagination reproduces both rhythm and sound, and it is often difficult to tell which was the last real stroke. So of a baby crying in a distant part of the house, we are uncertain whether we still hear it, or only imagine the sound. Certain violin-players take advantage of this in diminuendo terminations. After the pianissimo has been reached they continue to bow as if still playing, but are careful not to touch the strings. The listener hears in imagination a degree of sound fainter still than the preceding pianissimo. This phenomenon is not confined to hearing:

"If we slowly approach our finger to a surface of water, we often deceive ourselves about the moment in which the wetting occurs. The apprehensive patient believes himself to feel the knife of the surgeon whilst it is still at some distance."[80]

Visual perception supplies numberless instances in which the same sensation of vision is perceived as one object or another according to the interpretation of the mind. Many of these instances will come before us in the course of the next two chapters; and in