The Principles of Psychology, Vols. 1-2

f To say the very least, he always brought his articulatory iunervation close to the discharging point. Herr M. describes a tightening of the headmuscles as characteristic of the attitude of attention to the reply. this preliminary sub-excitement of motor tracts failed to occur, and the entire process of answering had to be gone through with after the question was heard. No wonder that the time was prolonged. It is a beautiful example of the summation of stimulations, and of the way in which expectant attention, even when not very strongly focalized, will prepare the motor centres, and shorten the work which a stimulus has to perform on them, in order to produce a given effect when it comes.

We have now a sufficient number of facts to warrant our considering this more recondite question. And two physi ological processes, of which we have got a glimpse, imme diately suggest themselves as possibly forming in combina tion a complete reply. I mean 1. The accommodation or adjustment of the sensory or gans ; and 2. The anticipatory preparation from loithin of the ideational centres concerned with the object to which the attention is paid.

1. The sense-organs and the bodily muscles which favor their exercise are adjusted most energetically in sensorial attention, whether immediate and reflex, or derived. But there are good grounds for believing that even intellectual attention, attention to the idea of a sensible object, is also accompanied with some degree of excitement of the senseorgans to which the object appeals. The preparation of the ideational centres exists, on the other hand, wherever our interest in the object — be it sensible or ideal — is de rived from, or in any way connected with, other interests, or the presence of other objects, in the mind. It exists as well when the attention thus derived is classed as passive as when it is classed as voluntary. So that on the whole we may confidently conclude — since in mature life we never attend to anything without our interest in it being in some degree derived from its connection with other objects — that the two processes of sensorial adjustment and ideational prep aration probably coexist in all our concrete attentive acts.

The two points must now be proved in more detail. First, as respects the sensorial adjustment. That it is present when we attend to sensible things is obvious. When we look or listen we accommodate our eyes and ears involuntarily, and we turn our head and body as well ; when we taste or smell we adjust the tongue, lips, and respiration to the object ; in feeling a surface we move the palpatory organ in a suitable way ; in all these acts, be sides making involuntary muscular contractions of a pos itive sort, we inhibit others which might interfere with the result — we close the eyes in tasting, suspend the respiration in listening, etc. The result is a more or less massive or ganic feeling that attention is going on. This organic feel ing comes, in the way described on page 302, to be con trasted with that of the objects which it accompanies, and regarded as peculiarly ours, whilst the objects form the notme. We treat it as a sense of our own activity ', although it comes in to us from our organs after they are accommo dated, just as the feeling of any object does. Any object, if immediately exciting, causes a reflex accommodation of the sense-organ, and this has two results — first, the object's increase in clearness ; and second, the feeling of activity in question. Both are sensations of an ' afferent ' sort.

But in intellectual attention, as we have already seen, (p. 300), similar feelings of activity occur. Fechner was the first, I believe, to analyze these feelings, and discriminate them from the stronger ones just named. He writes : " When we transfer the attention from objects of one sense to those of another, we have an indescribable feeling (though at the same time one perfectly determinate, and reproducible at pleasure), of altered direction or differently localized tension (Spannung). We feel a strain forward in the eyes, one directed sidewise in the ears, increasing with the degree of our attention, and changing according as we look at an object carefully, or listen to something attentively ; and we speak ac cordingly of straining the attention. The difference is most plainly felt when the attention oscillates rapidly between eye and ear ; and the feeling localizes itself with most decided difference in regard to the various sense-organs, according as we wish to discriminate a thing deli cately by touch, taste, or smell.

" But now I have, when I try to vividly recall a picture of memory or fancy, a feeling perfectly analogous to that which I experience when I seek to apprehend a thini? keenly by eye or ear; and this analogous feel ing is very differently localized. While in sharpest possible attention to real objects (as well as to after-images) the strain is plainly forwards, and when the attention changes from one sense to another only alters its direction between the several external sense-organs, leaving the rest of the head free from strain, the case is different in memory or fancy, for here the feeling withdraws entirely from the external sense-organs, and seems rather to take refuge in that part of the head which the brain fills ; if I wish, for example, to recall a place or person it will arise be fore me with vividness, not according as I strain my attention forwards, but rather in proportion as I, so to speak, retract it backwards." *

In myself the ' backward retraction ' which is felt during attention to ideas of memory, etc., seems to be principally constituted by the feeling of an actual rolling outwards and upwards of the eyeballs, such as occurs in sleep, and is the exact opposite of their behavior when we look at a physical thing. I have already spoken of this feeling on page 300. f f I must say that I am wholly unconscious of the peculiar feelings in the scalp which Feclmer ^oes on to describe. " The feeling of strained attention in the different sense-organs seems to be only a muscular one pro duced in using these various organs by setting in motion, by a sort of reflex action, the muscles which belong to them. One can ask, then, with what particular muscular contraction the sense of strained attention in the effort to recall something is associated? On this question my own feeling gives me a decided answer; it comes to me distinctly, not as a sensation of ten sion in the inside of the head, but as a feeling of strain and contraction in the scalp with a pressure from without inwards over the whole cranium, undoubtedly caused by a contraction of the muscles of the scalp. This harmonizes very well with the German popular expression den Kopf zusammenneJimen, etc., etc. In a former illness, in which I could not endure the slightest effort of continuous thought, and had no theoretical bias on this question, the muscles of the scalp, especially those of the occiput, assumed a fairly morbid degree of sensibility whenever I tried to think." (Ibid, pp. 490-491.) In an early writing by Professor Mach, after speak ing of the way in which by attention we decompose complex musical sounds v ''o their elements, this investigator continues: "It is more than a figure c f qjeech when one says that we 'search ' among the sounds. This hearkening search is very observably a bodily activity, just like attentive looking i \ the case of the eye. If, obeying tbe drift of physiology, we understand by attention nothing mystical, but a bodily disposition, it is most natural to seek it in the variable tension of the muscles of the ear. Just so, what common men call attentive looking reduces itself mainly to accommodating and setting of the optic axes. . . .

According to this, it seems to me a very plausible view that quite generally Attention has its seat in the mechanism of the body. If nervous work is being done through certain channels, that by itself is a mechanical ground for other channels being closed." (Wien. Sitzungsberichte, Math. Naturw., XLVIII. 2. 297. The reader who doubts the presence of these organic feel ings is requested to read the whole of that passage again. It has been said, however, that we may attend to an object on the periphery of the visual field and yet not accommodate the eye for it. Teachers thus notice the acts of children in the school-room at whom they appear not to be looking. Women in general train their peripheral visual attention more than men. This would be an objection to the invariable and universal presence of movements of ad justment as ingredients of the attentive process. Usually, as is well known, no object lying in the marginal portions of the field of vision can catch our attention without at the same time ' catching our eye ' — that is, fatally provoking such movements of rotation and accommodation as will focus its image on the fovea, or point of greatest sensibility. Practice, however, enables us, with effort, to attend to a marginal object whilst keeping the eyes immovable. The object under these circumstances never becomes perfectly distinct — the place of its image on the retina makes dis tinctness impossible — but (as anyone can satisfy himself by trying) we become more vividly conscious of it than we were before the effort was made. Helmholtz states the fact so strikingly that I will quote his observation in full. He was trying to combine in a single solid percept pairs of stereo scopic pictures illuminated instantaneously by the electric spark. The pictures were in a dark box which the spark from time to time lighted up ; and, to keep the eyes from wandering betweenwhiles, a pin-hole was pricked through the middle of each picture, through which the light of the room came, so that each eye had presented to it during the dark intervals a single bright point. "With parallel optical axes the points combined into a single image ; and the slightest movement of the eyeballs was betrayed by this image at once becoming double.

Helmholtz now found that simple linear figures could, when the eyes were thus kept immovable, be perceived as solids at a single flash of the spark. But when the figures were complicated photo graphs, many successive flashes were required to grasp their totality. " Now it is interesting," he says, "to find that, although we keep steadily fixating the pin-holes and never allow their combined image to break into two, we can, nevertheless, before the spark comes, keep our attention voluntarily turned to any particular portion we please of the dark field, so as then, when the spark comes, to receive an impression only from such parts of the picture as lie in this region. In this respect, then, our attention is quite independent of the position and accommo dation of the eyes, and of any known alteration in these organs; and free to direct itself by a conscious and voluntary effort upon any selected portion of a dark and undifferenced field of view. This is one of the most important observations for a future theory of attention." *

" Whilst attending to the marginal object we must always," he says, " attend at the same time to the object directly fixated. If even for a single instant we let the latter slip out of our mind, our eye moves towards the former, as may be easily recognized by the after-images produced, or by the muscular sounds heard. The case is then less properly to be called one of translocation, than one of unusually wide dispersion, of the attention, in which dispersion the largest share still falls upon the thing directly looked at," t

and consequently directly accommodated for. Accommoda tion exists here, then, as it does elsewhere, and without it we should lose a part of our sense of attentive activity. In fact, the strain of that activity (which is remarkably great in the experiment) is due in part to unusually strong contrac tions of the muscles needed to keep the eyeballs still, which produce unwonted feelings of pressure in those organs. 2. But if the peripheral part of the picture in this ex periment be not physically accommodated for, what is meant by its sharing our attention ? What happens when we '-distribute ' or ' disperse 5 the latter upon a thing for which we remain unwilling to ' adjust ' ? This leads us to that second feature in the process, the ' ideational preparation ' of which we spoke. The effort to attend to the marginal region of the picture consists in nothing more nor less than the effort to form as clear an idea as is possible of what is there portrayed. The idea is to come to the help of the sensation and make it more distinct. It comes with effort, and such a mode of coming is the remaining part of what we know as

our attention's ( strain ' under the circumstances. Let us show how universally present in our acts of attention this reinforcing imagination, this inward reproduction, this an ticipatory thinking of the thing we attend to, is. It must as a matter of course be present when the atten tion is of the intellectual variety, for the thing attended to then is nothing but an idea, an inward reproduction or con ception. If then we prove ideal construction of the object to be present in sensorial attention, it will be present every where. When, however, sensorial attention is at its height, it is impossible to tell how much of the percept comes from without and how much from within ; but if we find that the preparation we make for it always partly consists of the creation of an imaginary duplicate of the object in the mind, which shall stand ready to receive the outward impression as if in a matrix, that will be quite enough to establish the point in dispute.

In Wundt's and Exner's experiments quoted above, the lying in wait for the impressions, and the preparation to react, consist of nothing but the anticipatory imagination of what the impressions or the reactions are to be. Where the stimulus is unknown and the reaction undetermined, time is lost, because no stable image can under such cir cumstances be formed in advance. But where both nature and time of signal and reaction are foretold, so completely does the expectant attention consist in premonitory imagina tion that, as we have seen (pp. 341, note, 373, 377), it may mimic the intensity of reality, or at any rate produce reality's motor effects. It is impossible to read Wundt's and Exner's pages of description and not to interpret the 'Apperception ' and ' Spannung ' and other terms as equiva lents of imagination. With Wundt, in particular, the word Apperception (which he sets great store by) is quite inter changeable with both imagination and attention. All three are names for the excitement from within of ideational brain-centres, for which Mr. Lewes's name of preperception seems the best possible designation.

Where the impression to be caught is very weak, the way not to miss it is to sharpen our attention for it by pre liminary contact with it in a stronger form. "If we wish to begin to observe overtones, it is advisable, just before the sound which is to be analyzed, to sound very softly the note of which we are in search. . . . The piano and harmonium are well fitted for this use, as both give overtones that are strong. Strike upon the piano first the g' [of a certain musical example previously given in the text]; then, when its vibrations have objectively ceased, strike powerfully the note c, in whose sound g' is the third overtone, and keep your attention steadily bent upon the pitch of the just heard g' ; you will now hear this tone sounding in the midst of the c. ... If you place the resonator which corresponds to a certain overtone, for ex ample g' of the sound c, against your ear, and then make the note c sound, you will hear g' much strengthened by the resonator. . . . This strengthening by the resonator can be used to make the naked ear attentive to the sound which it is to catch. For when the resonator is gradually removed, the g' grows weaker ; but the attention, once directed to it, holds it now more easily fast, and the observer hears the tone g' now in the natural unaltered sound of the note with his unaided ear."*

" on carefully observing, one will always find that one tries first to recall the image in memory of the tone to be heard, and that then one hears it in the total sound. The same thing is to be noticed in weak or fugitive visual impressions. Illuminate a drawing by electric sparks separated by considerable intervals, and after the first, and often after the second and third spark, hardly anything will be recognized. But the confused image is held fast in memory ; each successive illumination completes it ; and so at last we attain to a clearer perception. The primary motive to this inward activity proceeds usually from the outer impression itself. We hear a sound in which, from certain associations, we suspect a certain overtone ; the next thing is to recall the overtone in memory ; and finally we catch it in the sound we hear. Or perhaps we see some mineral substance we have met before ; the impression awakens the memory-image, which again more or less completely melts with the impression itself. In this way every idea takes a certain time to penetrate to the focus of consciousness. And during this time we always find in ourselves the peculiar feeling of attention. . . . The phenomena show that an adaptation of attention to the impression takes place. The surprise which unexpected impressious give us is due essen tially to the fact that our attention, at the moment when the impression occurs, is not accommodated for it. The accommodation itself is of the double sort, relating as it does to the intensity as well as to the quality of the stimulus. Different qualities of impression require disparate

adaptations. And we remark that our feeling of the strain of our inward attentiveness increases with every increase in the strength of the impressions on whose perception we are intent." * The natural way of conceiving all this is under the sym bolic form of a brain-cell played upon from two directions. Whilst the object excites it from without, other brain-cells, or perhaps spiritual forces, arouse it from within. The latter influence is the 'adaptation of the attention.' The plenary energy of the brain-cell demands the co-operation of both fac tors : not when merely present, but when both present and attended to, is the object fully perceived.

A few additional experiences will now be perfectly clear. Helmholtz, for instance, adds this observation to the pas sage we quoted a while ago concerning the stereoscopic pictures lit by the electric spark. " These experiments," he says, "are interesting as regards the part which attention plays in the matter of double images. . . . For in pictures so simple that it is relatively difficult for me to see them double, I can succeed in seeing them double, even when the illumination is only instantaneous, the moment I strive to imagine in a lively way how they ought then to look. The influence of attention is here pure ; for all eye movements are shut out. "f

" When I have before my eyes a pair of stereoscopic drawings which are hard to combine, it is difficult to bring the lines and points that correspond, to cover each other, and with every little motion of the eyes they glide apart. But if I chance to gain a lively mental image (An- schauungsbild) of the represented solid form (a thing that often occurs by lucky chance), I then move my two eyes with perfect certainty over the figure without the picture separating again."

" It is not a trial of strength between two sensations, but depends on our fixing or failing to fix the attention. Indeed, there is scarcely any phenomenon so well fitted for the study of the causes which are capable of determining the attention. It is not enough to form the conscious intention of seeing first with one eye and then with the other ; we must form as clear a notion as possible of what we expect to see. Then it will actually appear." §

In figures 37 and 38, where the result is ambiguous, we can make the change from one apparent form to the other by imagining strongly in advance the form we wish to see. Similarly in those puzzles where certain lines in a picture form by their combination an object that has no connection with what the picture ostensibly represents ; or indeed in every case where an object is inconspicuous and hard to discern from the background ; we may not be able to see it for a long time ; but, having once seen it, we can attend to it again whenever we like, on account of the mental duplicate of it which our imagination now bears. In the meaningless French words ' pas de lieu Rhone que nous,' who can recognize immediately the English ' paddle your own canoe ' ? * But who that has once noticed the identity can fail to have it arrest his attention again ? When watch ing for the distant clock to strike, our mind is so filled with its image that at every moment we think we hear the longedfor or dreaded sound. So of an awaited footstep. Every stir in the wood is for the hunter his game ; for the fugi tive his pursuers. Every bonnet in the street is moment arily taken by the lover to enshroud the head of his idol. The image in the mind is the attention ; the preperception, as Mr. Lewes calls it, is half of the perception of the lookedfor thing, f

* Similarly in the verses which some one tried to puzzle me with the other day: " Oui n'a beau dit, gm sabot dit, nid a beau dit elle f " f I cannot refrain from referring in a note to an additional set of facts instanced by Lotze in his Medizinische Psychologic, § 431, although I am It is for this reason that men have no eyes but for those aspects of things which they have already been taught to discern. Any one of us can notice a phenomenon after it has once been pointed out, which not one in ten thousand could ever have discovered for himself. Even in poetry and the arts, some one has to come and tell us what aspects we may single out, and what effects we may admire, before our aesthetic nature can * dilate ' to its full extent and never 'with the wrong emotion.' In kindergarten instruction one of the exercises is to make the children see how many features they can point out in such an object as a flower or

not satisfied with the explanation, fatigue of the sense-organ, which lie gives. " Iii quietly lying and contemplating a wall-paper pattern, some times it is the ground, sometimes the design, which is clearer and conse quently comes nearer. . . . Arabesques of monochromic many-convoluted lines now strike us as composed of one, now of another connected linealsystem, and all without any intention on our part. [This is beautifully seen in Moorish patterns ; but a simple diagram like Fig. 39 also shows it well. We see it sometimes as two large triangles superposed, some times as a hexagon with angles spanning its sides, sometimes as six small triangles stuck together at their corners.] . . . Often it hap pens in revery that when we stare at a picture, suddenly some one of its features will be lit up with es pecial clearness, although neither its optical character nor its mean ing discloses any motive for such an arousal of the attention. . . . To one in process of becoming drowsy the surroundings alter nately fade into darkness and abruptly brighten up. The talk of the bystanders seems now to come FlG- 39>

from indefinite distances; but at the next moment it startles us by its threatening loud ness at our very ear," etc. These variations, which everyone will have noticed, are, it seems to me, easily explicable by the very unstable equilibrium of our ideational centres, of which constant change is the law. We conceive one set of lines as object, the other as background, and forthwith the first set becomes the set we see. There need be no logical motive for the conceptual change, the irradiations of brain-tracts by each other, according to accidents of nutrition, 'like sparks in burnt-up paper,' suffice. The changes during drowsiness are still more obviously due to this cause.

a stuffed bird. They readily name the features they already, such as leaves, tail, bill, feet. But they may look for hours without distinguishing nostrils, claws, scales, etc., until their attention is called to these details ; thereafter, however, they see them every time. In short, the only things which we commonly see are those which we preperceive. and the only things which we preperceive are those which have been labelled for us, and the labels stamped into our mind. If we lost our stock of labels we should be intellect ually lost in the midst of the world.

Organic adjustment, then, and ideational preparation or preperception are concerned in all attentive acts. An interest ing theory is defended by no less authorities than Professors Bain * and Eibot,t and still more ably advocated by Mr. N. Lange, :|: who will have it that the ideational preparation itself is a consequence of muscular adjustment, so that the latter may be called the essence of the attentive process throughout. This at least is what the theory of these authors practically amounts to, though the former two do not state it in just these terms. The proof consists in the exhibition of cases of intellectual attention which organic adjustment accompanies, or of objects in thinking which we have to execute a movement. Thus Lange says that when he tries to imagine a certain colored circle, he finds himself first making with his eyes the movement to which the circle corresponds, and then imagining the color, etc., as a conse quence of the movement.

" Let my reader," he adds, " close his eyes and think of an extended object, for instance a pencil. He will easily notice that he first makes a slight movement [of the eyes] corresponding to the straight line, and that he often gets a weak feeling of innervation of the hand as if touch ing the pencil's surface. So, in thinking of a certain sound, we turn towards its direction or repeat muscularly its rhythm, or articulate an imitation of it. " § § See Lange, loc. cit. p. 417, for another proof of his view, drawn from the phenomenon of retinal rivalry.

But it is one thing to point out the presence of muscu lar contractions as constant concomitants of our thoughts, and another thing to say, with Herr Lange, that thought is made possible by muscular contraction alone. It may well be that where the object of thought consists of two parts, one perceived by movement and another not, the part per ceived by movement is habitually called up first and fixed in the mind by the movement's execution, whilst the other part comes secondarily as the movement's mere associate. But even were this the rule with all men (which I doubt *), it would only be a practical habit, not an ultimate necessity. In the chapter on the Will we shall learn that movements themselves are results of images coming before the mind, images sometimes of feelings in the moving part, some times of the movement's effects on eye and ear, and some times (if the movement be originally reflex or instinctive), of its natural stimulus or exciting cause. It is, in truth, contrary to all wider and deeper analogies to deny that any quality of feeling whatever can directly rise up in the form of an idea, and to assert that only ideas of movement can call other ideas to the mind.

So much for adjustment and preperception. The only third process I can think of as always present is the inhibi tion of irrelevant movements and ideas. This seems, how ever, to be a feature incidental to voluntary attention rather than the essential feature of attention at large, t and need * Many of my students have at my request experimented with imagined letters of the alphabet and syllables, and they tell me that they can see them inwardly as total colored pictures without following their outlines with the eye. I am myself a bad vistializer, and make movements all the while. — M. L. Marillier, in an article of eminent introspective power which appeared after my text was written (Remarques sur le Mecanisme de 1'At- tention, in Revue Philosophique, vol. xxvn. p. 566), has contended against Ribot and others for the non-dependence of sensory upon motor images in their relations to attention. I am glad to cite him as an ally.

f Drs. Ferrier (Functions of the Brain, §§ 102-3) and Obersteiner (Brain, i, 439 ff.) treat it as the essential feature. The author whose treatment of the subject is by far the most thorough and satisfactory is Prof. G. E. Muller, whose little work Zur Theorie der siunlichen Aufrnerksamkeit, Inauguraldissertation, Leipzig, Edelmann (1874?), is for learning and acuteness a model of what a monograph should be. I should like to have quoted from it, but the Germanism of its composition makes quotation quite

not concern us particularly now. Noting merely the inti« mate connection which our account so far establishes be tween attention, on the one hand, and imagination, discrim ination, and memory, on the other, let us draw a couple of practical inferences, and then pass to the more speculative problem that remains. The practical inferences are pedagogic. First, to strengthen attention in children who care nothing for the sub ject they are studying and let their wits go wool-gathering. The interest here must be * derived ' from something that the teacher associates with the task, a reward or a punish ment if nothing less external comes to mind. Prof. Kibot says: