Psychology
Chapter 4: Attention, Discrimination, and Association
James Rowland Angell
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Consciousness and Attention -- We announced our purpose at the outset to adopt a biological point of view in our psychological study, and to attempt at every step to see just how the mind aids in the adjustment of the psychophysical human organism to its environment. If we turn from the merely general statement that the fundamental function of consciousness is to better such adaptive activities, and observe any specific instances of the process of adaptation itself, we shall always find that the actual work of accommodation is going on at the point which we call the point of attention. Attention, we shall accordingly discover, represents the very heart of consciousness, its most important centre of vitality. It therefore deserves our careful notice.
In a vague fashion we all recognise this rudimentary significance of attention. Thus we speak of the awakening of the new-born infant's mind when we first see signs that the child is attending to something. Moreover, we roughly measure the growth of children in intellectual maturity and power by their increasing ability to give prolonged attention to definite trains of thought. Alienists and specialists in nervous disorders inform us that mental disease is commonly accompanied by disturbance in the power of attention. In some forms of neurasthenia the attention is extremely unstable and irritable, flitting from one subject to another with feverish haste. In mania there is often a similar, but much exaggerated, attention to the flow of disconnected ideas. In melancholia, on the other hand, as in the milder types of neurasthenic hypochondria, attention is morbidly fascinated
(65) by some single idea, or group of ideas, and cannot be long lured away to the normal business of life.
Definition of Attention.-- When we attempt a definition of attention we experience the same sort of difficulty which we met in defining consciousness, and for a similar reason. So long as we are conscious at all, attention in some degree is present. We therefore find it difficult to define it without employing the thing itself in the definition. Because of this fact, attention has been commonly referred to as a " general, or universal, characteristic of consciousness." In default of a wholly satisfactory definition of attention, we may at least illustrate what we mean by the term. When we look at a printed page there is always some one portion of it, perhaps a word, which we see more clearly than we do the rest; and out beyond the margin of the page we are still conscious of objects which we see only in a very imperfect way. The field of consciousness is apparently like this visual field. There is always a central point. of which we are momentarily more vividly conscious than of anything else. Fading gradually away from this point into vaguer and vaguer consciousness, is a margin of objects, or ideas, of which we are aware in a sort of mental indirect vision. This fact that consciousness always has a focal point, which reveals the momentary activity of the mind, is what is meant by the fact of attention, so far as it can be described in terms of the content of consciousness. Baldwin has suggested the accompanying diagrammatic presentation of the facts we are speaking of, in connection with certain others. (Figure 33.) The margin of mental processes, outside the focal point of attention, constitutes what James calls the " fringe of consciousness." Whether we are attending to objects in the world about us,, or to ideas in our own minds, there is always such a fringe, partly made up of sensations, partly of ideas. No matter what we are especially attending to, we are never completely oblivious to all other sensory and ideational processes.
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The direction of attention to any part of the field of consciousness is
commonly accompanied by a certain increase in duration, together with a certain clarifying
and intensifying of this part, as compared with the remainder of the field, which is thus
inhibited from further entrance into the mental region. Thus, if we give our definite
attention to a musical note we remark its exact quality much more perfectly than when we
simply listen to it in a casual way. It is apt to seem more intense, and it certainly
tends to linger longer in the mind. Statements of this kind bring out the fact that we use
the term attention at times as virtually synonymous with mental activity. To turn the
attention to an object is simply to direct one's mental activity toward it. Now, our
mental activity, considered as directive, is commonly called conation, and we must
accordingly conclude that attention is a rudimentary form of conation, or will. This is
unquestionably true. We see, then, that attention is capable of being considered in two
different ways. We may emphasise the mere fact of mental activity, illustrated by all
attending; or we may dwell upon the structure of any moment of such attentive
consciousness, and note the fact of its containing a focal point, with a fading margin.
But our emphasis upon one or other of these phases of attention does not alter the fact
that the mental process, which we describe in these two ways, is one and the same. In die
remainder of the chapter we shall therefore make no attempt rigidly to dissever these
aspects of every act of attention, although we shall be frankly most
(67) interested in attention as an instance of mental activity. Meantime, the best practical definition of attention is afforded by such an analysis and description of it as is contained in the remainder of this chapter.
The Selective Character of Attention. -- Probably the most striking characteristic of attention is its selective nature, and the significance of this function will grow more conspicuous as we examine the facts. We have seen that the nervous system is so constituted that by means of its sense organs it is capable of being affected by various forms of motion in the physical world, e.g., light, heat, sound, etc. This fact has itself sometimes been regarded as a form of cosmic, or organic, selection. Thus, of all the rates of vibration in the physical world, the retina responds only to those between the limits of approximately 440 billions and 790 billions per second. In a similar way the ear selects a certain group of sound vibrations, and so on for the other senses. Undoubtedly there are many forms of vibrations in the physical world to which we are wholly insensitive, because we have no sense organs appropriately attuned to their special rates, and are thus incapable of receiving them.
However all this may be, it is easy to convince oneself that innumerable stimulations of the kind to which we are sensitive are always falling upon the sense organs; and were we conscious of all of them at once our minds would present a curious conglomerate. As a matter of fact, only a few of these stimuli ever succeed in producing simultaneously that form of cortical reaction which accompanies consciousness, and consequently we are never at any one moment aware of more than a small part of them. Apparently the psychophysical organism selects from the wide range of potential objects those special ones which shall receive attention and so come to consciousness. Thus, when reading an entertaining book we may become altogether oblivions to the rattling of carts in the street, to the odour of the smoking lamp to the
(68) contact sensations from our clothing, etc. Similarly, when we are preoccupied with some train of thought our attention dwells upon this idea, and turns away from that, according as the one or the other appears to the mind to be relevant and useful for the business in hand. Indeed, were it not for the selective activity of attention exercised in the form of reasoning, it is clear that we could never make any consistent mental advance, but that we should always be at the mercy of our sporadic ideas. We can, perhaps, examine this selective function of attention to best advantage by analysing the principal forms in which attention is found to operate.
Forms of Attention.-- Probably the most fundamental division of attentive processes, and certainly one of the oldest, is that into active and passive, or, as they are better termed, voluntary and involuntary attention. A more satisfactory division, which we shall adopt, adds one more class, and recognises (1) voluntary, (2) non-voluntary, or spontaneous, and (3) involuntary attention,
Voluntary Attention.-- Active, or voluntary, attention is precisely what the name implies, attention as the result of definitely self-initiated activity. In its clearest and most unambiguous form it always involves mental strain and effort. Whenever we attend to anything because we explicitly will to, we are exercising active attention. It matters not what the object may be to which our minds are thus directed. It may be a sound or an odour, an object which we see, or an object which we touch; a thought in the mind itself, a memory, an emotion, or anything one pleases. So long as it is attended to, as the result of our definite purpose to give it attention, it must be regarded as involving a case of active attention.
That we are capable, within certain limits, of thus directing our mental activity wherever we will is one of the easiest of facts to verify introspectively. Probably the reader has found repeated occasion, before reaching the pres-
(69)-ent point in this book, to make just such voluntary efforts of attention to prevent his mind from wandering off to more attractive by-paths. Obviously the selective nature of attention, upon which we have already insisted so strongly is conspicuously in evidence in active attention. Moreover, it seems probable that this type of attention, involving, as it does, the purposeful direction of our thoughts, would in its fully developed form be a somewhat later achievement than the other forms, which require for their existence far less of experience. To direct one's thought involves the possession of purposes and plans, however rudimentary, and these are the outgrowth of experience and relative maturity. Young infants are hardly capable of voluntary attention in any proper sense, although they may achieve both non-voluntary and involuntary attention from the beginning.
Non-Voluntary Attention.-- It requires no extended reflection upon our everyday experience to reveal to us the fact that in the course of every twenty-four hours we attend in an effortless way to a great many things to which we have no explicit purpose to direct our thought, to which we cannot, therefore, be said to attend voluntarily in the full sense of the word; but to which we certainly are not attending against our will and in spite of ourselves. Such cases constitute what is meant by non-voluntary, or spontaneous, attention. A few illustrations may make the distinction clearer.
It happens not infrequently, for example, that we suddenly arouse to consciousness of the fact that for several minutes our minds have been running off on subjects quite disconnected from the special occupation with which we may at the moment be engaged. We have " lost ourselves," as we say, in some day dream, perhaps. Our prolonged attention to a subject which sincerely interests Lis is often of this same character. Our attention is not given as the result of any effort on our part. Rather should we find that it required effort to direct our attention elsewhere. It necessitates no
(70) strenuous act of will for the boy interested in athletics to give his attention to a newspaper account of a football game. On the contrary, his attention can only be obtained for less exciting themes by some artifice on your part, or by a selfsacrificing effort of volition upon his.
So far as these cases of non-voluntary attention reflect the actual nature of our interests, they must be regarded as affording peculiarly intimate information of the real character of our minds, and so of our wills. They are thus, in this particular, closely related to voluntary attention. After all, what I am interested in, is a very close synonym for what mentally and morally I am. Moreover, it is frequently, and probably with right, maintained that this non-voluntary, or spontaneous, form of attention is the primitive germ, out of which voluntary attention in the full meaning of the term has developed. Certainly something like this, combined at times with involuntary attention, appears to form the beginnings of infant attention. In any event it is clear that however sharply we may be able to mark off at times those instances in which we attend as the result of a definite purpose so to do from those instances in which we find the allurements of an interesting subject have drawn off our attention almost unnoticed, both cases reflect very accurately the texture and character of our minds. To the relationship of these two forms of attentive activity we shall return in a moment with greater fulness.
Involuntary Attention. -- However genuinely voluntary and non-voluntary attention may differ from one another, they neither of them involve attention given against the will. But there are numerous cases in which, at first sight, anyhow, this form of attention apparently occurs; and it is to this that the name " involuntary attention " has been given. Thus, for example, if the door slams while I am writing this sentence I am seemingly obliged to hear the sound, however much I might prefer not to do so. To be sure, if I am sufficiently
(71) preoccupied a very loud noise may in this way escape my notice; and the obliviousness to ordinary sounds, such as the ringing of the dinner-bell, the striking of the clock, etc., of persons thus engrossed in some interesting occupation is familiar to require comment. Archimedes, absorbed in his studies and unconscious of the sacking of Syracuse, is the classical illustration of this kind of thing.
But despite the fact that when one is thoroughly immersed in some congenial undertaking one becomes relatively insensitive to sensory stimuli, which otherwise would be noticed, the further fact obstinately remains that even under such conditions stimuli of sufficient intensity will force themselves into consciousness. Certainly we should all agree that in this way bright flashes of light, loud sounds, unpleasant odours, etc., repeatedly intrude themselves upon our attention distinctly against our wills. Moreover, there are experiences in which ideas, instead of sense impressions, thus force themselves in upon our attention against our wills. What are known as insistent ideas are of this character. The hypochondriac, for instance, is unable long to keep his attention away from his own bodily ailments, real or fancied. He may make a sincere effort to divert his mind, but in spite of him,self the unwelcome idea presently shows its face at the door and claims his recognition.
Less definitely morbid than such cases, and still illustrative of the imperious command exercised at times over our attention by certain ideas, are the intense experiences of the emotional kind. Great joy, great grief, great anxiety, brook no prolonged opposition. We may attempt to force our attention on to the lines of the day's work and for a moment ~succeed, only to find ourselves in the next moment once more mastered by the idea we had attempted to put behind us. ,~Certain psychologists would prefer not to give the name involuntary attention to these cases of attention against the will to ideas. But they are clearly more closely related to this
(72) form of attention, as illustrated by our forced attention to intense sensory excitation, than they are to the other classes we have distinguished; and we shall accordingly designate them as cases of involuntary attention.
Interrelations of the Forms of Attention.-- We have already intimated that involuntary and non-voluntary, or spontaneous, attention are genetically prior to voluntary attention. Undoubtedly the earliest experiences of a baby involve in largest measure spontaneous attention to sensory stimuli. The rude power with which some of these stimulations force themselves on the child's notice might give ground for the postulation of involuntary attention also. But if we confine the term "involuntary attention " strictly to such cases as those in which we attend against our wills, it is doubtful whether we ought often to apply the designation to a young child's attention; for we can hardly speak with confidence of the newborn child's possessing any resolution not to attend to a given stimulus. Spontaneous attention, then, working in the main upon the sensory material supplied by the physical surroundings, constitutes probably the earliest and most fundamental type of attention process.
Voluntary attention is apparently a derivative form of spontaneous attention, which may arise as soon as, and whenever, there is a tendency to the splitting of attention, a felt tendency to opposition against the direction our attentive energies are taking. Evidently this can only occur when we have developed intellectually to a sufficient degree to set over against some momentary disposition, or action, a more or less definitely formed plan involving interests and- purposes opposed to the present activities. When we say that in voluntary attention we force ourselves to attend to some particular object or idea, what we evidently mean is, that the mind in its entirety is brought to bear in suppressing certain disturbing objects or ideas, and in bringing to the front the chosen ones. The act of voluntary attention is, in short, an expression of
(73) the sovereignty of the whole mind over its lesser parts, i. e., ,over the disturbing or alluring ideas and sensations.
Now, spontaneous, or non-voluntary, attention is likewise in reality just such an expression of our total mental organisation at the moment. Those things to which we spontaneously .attend are the things to which our minds, by virtue of their temporary condition, inevitably go out. And if we took into account the entirety of these spontaneous acts of our attention for any considerable period of time, we should undoubtedly secure an extremely accurate portrait of the real constitution of our minds. In the sense, therefore, upon which we commented briefly in an earlier paragraph of the chapter, nonvoluntary attention is itself an expression of the individuality of the mind, and thus an expression of the true source of our volitional acts. It is a sort of voluntary attention, in which there is no internal, mental opposition to be overcome, and from which we are consequently apt to feel one characteristic fact of complete volition has been subtracted. But this does not detract from the fact that such spontaneous attention is in reality an expression of the mental organisation, quite as truly, if not so completely, as voluntary attention. It 'appears, then, that the distinction between voluntary and nonvoluntary attention is not absolute, in the sense that we can always determine without question to which class a specific case of attention belongs. Quite the contrary. It appears that there is a gradual transition from one class to the other, ,through cases which partake of the characteristics of both forms.
Thus, for example, we should have to admit the existence of many cases in which it would be all but impossible to say 'Whether we were attending to certain subjects as the result of a definite purpose and an explicit effort to attend, or as the result of more or less unconscious mental drifting. What shall one say, for instance, of the attention which is given to the routine duties of daily life? Some of them undoubtedly
(74) require definite, purposeful attention. Others enlist our spontaneous interest, require no effort and reveal little or no antecedent purpose to attend. Many others are surely on the border line, where it is not easy to say whether our attention is altogether due to spontaneous interest or to preconceived purpose. Meantime, we must admit that it is in voluntary attention that consciousness raises the human being into the greatest freedom from mere routine, with the greatest independence from mere temporary surroundings.
The Psychophysical Organism and the Forms of Attention. -- The true relation of involuntary attention to voluntary and non-voluntary attention can hardly be understood without reference to the psychophysical organism as a whole. But fortunately we have all along taken this into account, and our present mention of it will mark no change in our point of view.
So far as concerns such instances as those in which we are forced against our will, or at all events without our mental consent, to notice intense sensations, it would seem that involuntary attention must be fundamentally opposed to voluntary attention at least, whatever might prove to be the case as regards non-voluntary attention. The one form of attention expresses the will, the other either defies, or disregards, the will. Such differences certainly appear to be fundamental; but we- shall see reason to modify this view, when we consider that both forms of attention are vital functions which are brought out and developed in the general adaptive reaction of the organism to its social and physical surroundings. If we remember that those objects which are harmful to us commonly stimulate the nerves very violently, we shall begin to see how in the general economy of the organism it may be useful to have our senses so constructed that they shall call our attention to such possible sources of danger as are represented by these intense stimuli, even when we do not consciously desire to have our quiet thus invaded. We shall
(75) begin to see that in the interests of the continuation of life and health it may be desirable that loud sounds and extreme temperatures, intense lights and violent odours, should have the power to elicit the attentive reaction from us. In a sense, therefore, such reactions are instances of a kind of organic selection from among various movements of just those which all result in our making momentary accommodation to the invading stimulus. If it prove really menacing, we may then take to flight, or adopt such other precautionary measures as situation demands. If it be, in point of fact, innocuous insignificant, our minds are left free to revert to the interrupted occupation. Involuntary attention of this kind represents, accordingly, the protest of the primarily physiological portion of the organism against a too complete subserviency merely intellectual conscious processes.
Involuntary attention is only involuntary when the mind viewed in isolation from the body. It is a kind of spontaneous bodily attention, and it is undoubtedly selective in a true enough sense. Moreover, even when viewed from the mental side alone, such attention could only properly be called voluntary, never passive. The term passive is quite miseading. involuntary attention, once it is aroused, is just as genuinely a form of mental activity as is voluntary attention. Its antecedents, both mental and physical, are in part different and often its consequences are different too. But both operations are mental acts, and neither of them can properly be designated in terms of pure passivity.
In all forms of attention, then, we find selective activity going on. Selection always implies a purposive, forward-looking type of action, and this is precisely what attention is in all its forms. It stands for the fact that the organism is teleological in its very constitution. That is to say, the organism contains within itself certain ends to be attained in course of development by adjustive activities. In part these ends exist imbedded in the physiological mechanisms, where
(76) they come to light as reflex, automatic, and instinctive acts, sometimes accompanied by consciousness; and in part they exist as conscious purposes, in which case they appear as recognised intentions.
In spontaneous attention the selection seems to be psychically originated and directed, but it occurs without effort, even though the end to be achieved is clearly recognised and elaborately planned for. Voluntary attention also appears to involve a distinctly mental origin for selection, and we have no new factors here, save the presence of psychical conflict and the feeling of effort. We have seen that in voluntary attention this effort is always internal and mental --an effort to conquer our own impulses, or thoughts, in the interests of the end to which we are attempting to attend. It is thus sharply distinguishable from. the effort to overcome merely external obstacles -- a type of effort that often characterises spontaneous attention. Finally, in involuntary attention the selective activity is still clearly present, but its locus appears now to have been transferred from the distinctly mental to the more definitely physiological side of the organism. Of course, in our speaking of voluntary and non-voluntary attention as being primarily psychical in their nature, it must not be understood that we mean to deny the presence of neural processes accompanying these activities. All we mean is, that the selective action shows itself to us in these instances primarily as a mental event. In involuntary attention it appears primarily as a physiological event. Both groups of attentive activity, however, have the double psychophysical characteristic.
Duration of Attention.-- It is extremely difficult to secure reliable information as to the length of time we can and do attend to objects in non-voluntary and involuntary attention; for the conditions in these forms of attention are necessarily very unfavourable to accurate introspection. But having discovered that the differences among the several forms of atten-
(77)-tion are relative and not absolute, we may, perhaps, safely assume that the facts which we find in voluntary attention are fairly representative of the other forms, and these facts are fortunately rather easy to make out. All voluntary attention displays a more or less rhythmic pulse, the duration of which varies considerably under different conditions. If we attempt to attend to a letter on this page, we shall find that we can only do this for a moment or two, unless we constantly observe something new about it. Otherwise we invariably find, either that the eye has moved away to something else, or that the mind has wandered off on to an entirely different subject. However constant the physical object may remain to which we thus attend, we can only continue our attention to it provided we continually see it in some fresh fashion; provided, that is to say, that the mental object keeps changing. This seems to be a fundamental law of our mental life, and did space permit we might profitably enlarge at some length upon its implication. A few consequences we may properly pause to mention.
Consequences of Shifting Attention. -- Evidently change is the primal law of mental life, as well as of bodily life. Thought processes which cease to move, cease to exist. They simply go out. To keep a thought alive we must keep turning it over, keep doing something with it. Mental paralysis is mental death. It is a familiar experience with all of us, especially with students, that occasionally when a question is asked us our minds either become perfectly blank, or remain for a moment stupidly confronting the mere sound of the words addressed to us. In such a case the only salvation lies in doing something, doing almost anything is better than such quiescence. Often to begin speaking is sufficient to break the spell, however pointless our remarks may be. The act of speech starts up the cerebral machinery and presently, if we keep our composure, we get our thought once more in movement. Similarly, the boy told to think about what he is
(78) studying finds himself, in the effort to execute the injunction with laid upon him, simply surveying the page before him an apathetic gaze. He is merely exposing himself innocuously to the light waves proceeding from the page. Mentally he is either in a condition of partial asphyxiation, or his mind is off engaged upon something really of interest to him. He is not in any proper sense attending to the subject matter of his work at all. For such a youth the sole possibility of progress consists in taking the topic and forcing his attention to turn it over, ask questions of it, examine it from new sides. Presently, even though such questions and inspections be very foolishly conceived, the subject will start into life, will begin to connect itself with things he already knows, will take its place in the general furniture of his mind; and, if he takes the next and all but indispensable step, and actually puts his rudimentary information to some use, applies it to some practical problem, incorporates it, perhaps, in an essay, or even talks about it with others, he will find he has acquired a real mental tool which he can use, and not simply a dead load which must be carried on his already aching back. What we call attending to a topic for a considerable period of time will, therefore, always be found to consist in attending to changing phases of the subject. Thus, to fix one's mind upon history for an hour or two will involve attending to hundreds of thoughts about the special historical subject, or problem, with which we are concerned. Accordingly, these instances of the practical continuation of attention to a single subject strongly confirm our position, instead of contradicting it, as might seem at first sight to be the case.
Why Attention Shifts. -- It has been suggested that the rapid changes of attention are due primarily to fatigue in the delicate cortical cells which are connected with conscious processes. Whether this statement be accepted or not, we gain a very significant suggestion in explanation of these changes, when we remember what the essential function of attention
(79) appears to be. We remarked at the outset that attention is simply a name for the operation of the central, and most active, portion of the field of consciousness. We have all along maintained that consciousness is an organic function whose intrinsic occupation consists in furthering the adaptive responses of the organism to its life conditions. We have also pointed out that, if this conception be true at all, it is at the point of attention that we shall find the most obvious and important part of the adjusting activity in progress. Now, in the nature of the case, each particular act of adjustment must be of relatively brief duration. In the case of common objects in the world of sensations it consists as a rule merely in the recognition of the stimulus (e. g., as a colour, as a sound, as a book, or a word, etc.), with a motor response, which consists, perhaps, in some movement of the eyes or head, calculated either to bring to notice some new and useful phase of the stimulus, or to divert further attention altogether away from it. Thus we look, for instance, at a book, recognise it as the one for which we are searching, pick it up and proceed to examine it; in this way continuing the activity of attending to the book, but, as a matter of fact, continuing it in the form of attention to ever new features. The same sort of thing is true when our attention is occupied with ideas, instead of with sensations. In short, so far as attention is really an activity of the relating, adjusting kind, its work is done when the relation between the mind and the thing attended to is once established. This is the mental, as distinct from the physiological, part of the adjustment; and attention must go elsewhere, because it is intrinsically the adjusting act itself, and other things are demanding of the organism the same energies of adjustment. To retain our attention for any considerable period an object must, therefore, by changing its aspect, present itself as a new object, to which fresh responses can be made.
Range, or Scope, of Attention.-- The question is often
(80) asked: How many things can we attend to at once? Various answers have been given, some authorities maintaining that we can attend only to one object at a time, others insisting that we may attend to an indefinite number. We must sharply distinguish between the question in the form in which we have given it, and the question often, but erroneously, treated as synonymous with it, i. e., How many things can we do at one time ? We have seen in the preceding chapter that there is literally no limit to the number of things we can learn to do at once. It is, in this latter case, simply a question of how elaborate we can make our habitual motor activities. A skilled pianist, or a trained acrobat, may do dozens of things simultaneously. But the question of how many things we can attend to is much more puzzling.
The differences of opinion upon the matter are, however apparently due in the main to a failure to define with precision the underlying mental conditions. It is the view here adopted, that we never have more than one mental object before the mind at any one moment. This object may be complex, or simple, but if it is really present in its entirety to consciousness, it is cognised mentally as a single thing. To illustrate, we may take the case of perceiving a table, If we examine introspectively the manner in which we are conscious of such an object, when we allow the eyes to rest momentarily upon it, we find that we perceive it as a complex single object; not as four legs, plus a top, plus a colour, plus a particular shape, etc. Now, these characteristics of a table which we have mentioned all correspond to distinguishable parts of it, and we might speak in a certain sense of having attended to all these circumstances at once. But this would be an injudicious mode of expression, tending to confuse our ability to analyse the physical object, or our own conscious. ness of the object, with the fact of the manner in which we actually perceived it in our momentary glance. However many things, therefore, may be present to us at one moment,
(81) it seems probable that our consciousness is of all of them as a single mental object, which we may, nevertheless, immediately recognise as being complex in its constitution, meaning, and references. Indeed, we may go further, and say that in order to perceive an object as one, there must be some complexity in it, which we thus synthesise into a unit. A pure, undifferentiated conscious quality never does, and apparently never can, constitute the object of a cognising consciousness. Plurality is, in short, just as necessary for an object of attention as unity; but our mental activity always gives the stamp of unification to these plural particulars. How many such particulars can be brought together in any one act of consciousness is a practical problem for experimental psychology.
The various interesting experiments which have been performed to test the so-called scope of momentary consciousness must all be interpreted in the light of the foregoing considerations. Thus, we find that with momentary exposure we can cognise four or five letters, under proper conditions. When the letters make words the number which we can cognise in this instantaneous fashion quickly rises. To these facts we shall revert in another chapter.
Some sensations, which have become thoroughly dissociated from one another, seemingly refuse to come together at all into simultaneous objects. Thus, it seems altogether problematic whether we can attend to a sound and a colour simultaneously. We hear the sound and then the attention oscillates to the colour, or vice versa. The same thing is true of sensations of contact, when conjoined with either sound or colour. On the other hand, fusions of two kinds of sensations, like those of taste and smell, are of course always attended to as simultaneous. They are not sensed as two.
Inattention and Scattered, or Dispersed, Attention.-- Inattention is often spoken of as though it were a positive mental condition, just like attention. Asa matter of fact inattention
(82) to any subject simply means attention to some other subject. In school-children of various ages this condition is often exasperating to the last degree. Its cause, however, is not the absolute loss of attention, but the direction of it into some forbidden but attractive channel. Wandering, or sporadic, attention also is never, properly speaking, the negative of attention. It is simply the unstable, flitting, inefficient form of it. This condition is sometimes spoken of as scattered attention, and, when not due to actual mental disease, is certainly attributable, if long continued, to bad mental surroundings, i. e., surroundings which neither encourage nor give scope for the expression of native and normal interests. Dispersed attention is another much abused term. To have one's attention completely dispersed would be to become unconscious. The conditions properly describable by this term are illustrated in the general lowering of our mental alertness when we become drowsy. Mental distinctions of all kinds tend, under such circumstances, to become blurred and indefinite. The state is one of fading attention. Nevertheless, as long as we are conscious at all, we are always more clearly aware of some part of the field of thought than we are of the remainder. Our attention is never distributed evenly over the whole of the conscious field. If it ever were thus distributed, completely dispersed attention would, indeed, be realised.
Motor Accompaniments of Attention.-- In our description of attention thus far, we have made occasional reference to the part played by sense organs and brain; but this has been somewhat incidental, and we have hardly noticed at all the conspicuous position of muscular activities. To bring out the significant facts bearing on these matters it will be convenient to avail ourselves temporarily of another common classification of attentive processes, differing from that which we have employed. This is the division of attention as sensory, or ideational; a division which certain of our illustra-
(83) -tions have involved. All attention to objects stimulating the sense organs, every process, therefore, of sensation and perception, involves sensory attention. All attention to ideas, images, thoughts, etc., is ideational attention. The first type of activity involves both sense organ and brain, whereas the second type involves immediately only the brain.
In normal sensory attention muscular movements seem always to be concerned. These movements are accommodatory, and are calculated to put the sense organs in the best attitude to receive distinct impressions from the objects stimulating them. In vision, for example, if we see to best advantage, the eyes must converge upon the objects at which we are looking, the lenses must be accommodated to the distance of the object, and oftentimes the head must be turned, in order to permit the most effective visual operation. In hearing, we similarly tend to turn the head toward the source of the sound, or at all events, to turn in that direction the more sensitive of our ears. In taste, we press against the substance in the mouth with the tongue in order to detect most fully its flavour. In smelling, we inhale in order to bring the odorous particles against the olfactory membrane at the upper part of the nasal cavity. In touch, we explore the object with the hand, if we desire accurate information of its tactual characteristics. We End a similar state of things true, as regards all our sensations, when we make them the object of direct attention.
Each of these cases illustrates the function of the sensory-motor circuit. The light rays falling upon the retina set up currents in sensory nerves, which are transmitted to cells in control of the muscles of the eyes; and these in turn send out impulses, which result in convergence and accommodation. In some cases the sensory impulse may originate in a cortical centre, or in a sense organ other than that which experiences the modifications of the accommodatory movement. Thus, the hand may be moved in response to an idea, or in response
(84) to a stimulus from the eye, and not from the skin of the hand itself.
Psychologists have observed a similar kind of muscular accommodation when our attention is directed to intellectual processes. Thus, if we close our eyes and attempt to get a visual mental picture of some particular place, it will generally be found that the eyes tend to turn in the supposed direction of the imagined locality. In attempting to recall an odour we almost inevitably make slight movements of inhalation. In calling up images of taste- the tongue moves and salivation is stimulated. Furthermore, the effort to fix our attention firmly upon any train of thought is generally accompanied by a strong tendency to assume some specific bodily attitude, in which we somewhat unconsciously seek to prevent the distraction of our attention by outside disturbances. In this effort the brows are often wrinkled, the breathing impeded, the body bent over and held rigid, the hands clenched, the head tilted in this way or that, etc. The attitudes which we thus assume evidently share with the sense organ accommodations already mentioned, the function of putting the organism in the most advantageous position for meeting the special demand momentarily laid upon it. The psychophysical effort at concentration overflows in movements calculated to assist in reaching the desired end. The actual value of these movements probably varies greatly, and depends (1) upon their success in eliminating, or neutralising, the effect of the disturbing stimuli from without; and (2) in their contribution, through their cortical effects, toward the continuation of the ongoing activity.
Thus, if more nervous energy is being liberated than can be properly disposed of by the pathways of discharge involved in the special matter in hand, these overflow motor pathways may be called in to take care of the excess of neural activity, and so indirectly further the ongoing occupation. The involuntary muscular processes, such as those of respiration
(85) and circulation, also reflect the changes in attention. When attention is much perturbed, they display rapid and relatively violent oscillations. When, on the other hand, attention moves along smoothly, these motor reactions are also stable.
The motor activities which accompany processes of attention necessarily, at least in the case of the voluntary muscles, send back to the cortex sensory impulses, which then enter into the general field of consciousness to modify its complexion and tone. These are sometimes spoken of as the "strain sensations" of attention. It seems probable that there is a small group which characterises in some measure all attention, and that the use of any special sense, or any special form of ideational process, involves another specific and relatively constant group. The intensity of these sensations necessarily varies widely from time to time, and is commonly greatest in cases of intense voluntary attention. The muscles most regularly and most obviously affected are those of the face, throat, and chest, although the hand and other parts of the body may be involved. The breathing movements are almost sure to be involved in cases of vigorous attention.
Dr. Gordon has suggested another interesting explanation of the function of these strain sensations. It is possible that in attempting, for example, to force our attention along some mentally difficult path, we primarily crave more nervous excitement and stimulation, more push a tergo; and these muscular activities setting up definite sensory impulses, which return to the cortex, may possibly furnish this needed help. It may well be that all these accounts of the motor aspects of attention are correct. After what has been said it is, perhaps, unnecessary to insist that motor processes are bound up in an inextricable way with the movements of attention, both as leading up to its effective activity and as secondary consequences of its operation. The idea of the
(86) sensory-motor circuit proves to be radically implicated, therefore, in every form of conscious action.
Genetic Features of Attention.--All the evidence which we can command, coming in part from the examination of our own mental operations as adults, and in part from observing how children deal with the objects about them, points to the notion that attention is from the very first engaged in the double process of pulling apart and putting together the various elements of conscious experience. These two processes are commonly known as dissociation and association. It seems to be fairly certain that at the outset of life consciousness is extremely vague and crude in its organisation. To begin with, there is, perhaps, no definite distinction felt between the various kinds of sensations, visual, auditory, tactual, etc. Certainly the process of distinguishing the various kinds of sensory qualities within the range of any given sense series-like the spectral colours in the field of vision-is quite slow in developing. The various colours are undoubtedly distinguished from one another very imperfectly even up to a late period in childhood. Nevertheless, after the first moment of consciousness attention is constantly at work, splitting up experiences which previously were felt as simple, and bringing about an increasingly definite awareness of the several distinguishable qualities within them. The analytical activity of attention is what we called above dissociation, or discrimination. Although we shall have a great deal to say about it under other titles further on in the book, we must glance at some of its more conspicuous features here.
Analytic Activity of Attention.--Discrimination.-- When the different distinguishable elements of any state of consciousness blend with one another, so that they lose their individuality, we speak of the resulting condition as a case of fusion. Thus, the partial tones in a piano note are generally lost to us as separate sounds, and we seem to hear only a
(87) single musical tone. Similarly, when we grasp a book we seldom distinguish the sensations of pressure from those of temperature and tendinous strain. These sensations fuse. Again, the sensations which we got when eating onions, or when drinking coffee, we commonly speak of as being tastes. In point of fact, they largely depend for their characteristic quality upon smell sensations, which fuse with the tastes and in consequence are entirely overlooked by us. Now, it seems probable that the original tendencies of all sensory stimuli, which impinge upon our sense organs simultaneously, is to fuse in just this same fashion; so that were it not for this discriminative action of attention which we are describing, we might remain oblivious to much of the complexity of the objective world. Meantime, it must not be overlooked that once attention has succeeded in analysing some of these originally fusing qualities, we may find their distinctness and separateness enhanced by being experienced simultaneously. Colours, like black and white, red and green, may gain in definiteness and individuality by the contrast effects of juxtaposition.
However it may be in later life, there can be no question that during the first year or two the great agent in furthering discrimination is the change in the objective stimuli, which affect the sense organs from moment to moment. Thus, sounds sometimes occur simultaneously with stimulations of colour, and sometimes they do not. Stimulations of red sometimes occur together with stimulations of blue, and sometimes with white. These changes in the mode of sensory stimulation necessarily produce different forms of cortical reaction; and, as consciousness is conditioned by these cortical activities, we have thus a basis for different states of consciousness. That we are able to recognise the fact that one state of consciousness differs from a second, and is like a third, is an ultimate fact which we cannot further explain. All psychologists agree that this is a fundamental attribute
(88) of consciousness, and, so far as concerns the conditions under which we actually come in the first instance to attain this awareness of differences, the description we have just given seems to represent the undoubted facts. We can put the matter diagrammatically, as in figure 34. So long as a certain taste sensation T, and a certain smell sensation S, are always given us together, we fail to note the complexity of the sensation, and we experience a fusion possessing a
single quality, 1 Q. When, however, the taste sensation happens to be combined with some sensation X other than the previous smell, we can then note the fact that TX contains two qualities -- 2 Q; and if S happens to be combined also with this X we may immediately note the three qualities S, X and T. In each case we have, by varying the concomitants, produced a new psychical condition, different from its predecessors, and in this way we have provided the prerequisites of discrimination.
Evidently, if these are the preconditions of our original capacity for the dissociating activity of attention, any device which facilitates the arousal of different nervous conditions will assist us in making our discriminations. Submitting objects to successive, instead of simultaneous, inspection produces a maximum of nervous difference; and we find accordingly that if we wish, for example, to detect the heavier of two objects of nearly equal weight, we judge most accurately when we lift them immediately in succession. If we wish to tell whether or no two colours match, we let the eye pass rapidly from one to the other, etc. Of course, when the objects stimulate different sense organs there is already considerable difference in the nervous processes resulting, and
(89) to discriminate among them it is only necessary to let either sense be stimulated independently. The kind of discrimination, or comparison, which occurs among ideas in the higher processes of reflection, reasoning, etc., we shall consider at a later point. The form of dissociation which we have described clearly underlies the higher form, because it is concerned with our primary analysis into its rudimentary features of the world as we first know it.
Synthetic Features of Attention.--Simultaneous Association.-- Hand in band with these dissociative, analytical activities of attention is to be found a synthetic process, which serves to unite the various dissevered elements, and to which the name association is commonly given. In a logical sense, one phase of this associative process really precedes and underlies the dissociative activity; for it is evident that if we are to differentiate the two qualities A and B from one another, they must already be together in the mind; that is, they must be associated in some kind of fusion such as we, have just been describing. Thus, to distinguish the colour white from the colour black upon this printed page involves not only that the black and the white objects shall be side by side in the space before me, but also that they shall in a way be together in my mind.
It is clear that every act of attention must involve in some degree both discrimination and this form of " simultaneous association." We may' for example, remark that the colours upon a postage stamp are red and white. Such an act is evidently one of discrimination. But it is also quite as truly one of association, for the qualities must be experienced together, in-List be mentally synthesised, that this special kind of discrimination may occur at all.
Successive Association.-- There is another form of association, known as successive association, a term which is commonly restricted to the sequence of our ideas as they pass through the mind, and is not primarily and properly applied
(90) to our sensory and perceptual processes. We shall discuss it in connection with imagery and the higher cognitive functions. Even this kind of association of ideas, however, evidently involves discrimination; for the ideas must be noticed as different, in order that they may be separate ideas at all. And conversely, so far as we remark differences in successive moments of consciousness, we must admit the presence of associative factors of some kind or other, uniting the several temporally distinct contents of consciousness with one another.
Generalising, then, we may say that attention is both a synthetic and an analytic activity. Sometimes our primary purpose and interest in attending is to analyse and discriminate, but we cannot accomplish this without simultaneously employing association. And similarly, although we may be ostensibly engaged in connecting, or associating, the various items of our experience with one another, the execution of our task inevitably involves us in discrimination.
