' writ large ' in agoraphobia will help us to understand it as printed small and stamped lightly upon our own consciousness. So the exaggerated self-importance of paranoia throws light upon the state of mind which we describe by saying that we were ' self- conscious ' upon some social or public occasion.
(3) The third science to mention is physiology. The reader need only be reminded that one of the aims of the psychologist is to bring the simplest mental processes into connection with the bodily processes which they accompany. It is clear that he cannot accomplish this task, unless he have some knowledge of the different bodily organs, of the way in which they work together for various purposes, and of the part they play in the life of the whole organism.
Illustrations of the way in which physiology can aid psychology will be found throughout the following chapters of this book. One instance may suffice here.
§ 6. External Aids to Psychology 25 The psychological investigation of feeling (pleasantness and unpleasantness) is very difficult. Fortunately, every feeling has various bodily manifestations, in breathing, play of feature, etc., so that we can follow the course of a pleasure or disagreeableness by noting its physiological symptoms. Now it has been found that the bodily manifestations of the 'higher' feelings — joy, the pleasure of success, the pleasure of the performance of a duty; or shame, scorn, the dissatisfaction which follows failure — are the same as the bodily manifestations of the Mower' feelings, — the pleasure of a good meal, or the unpleasantness of bodily pain. Here is welcome confirmation of the conclusion reached, but reached with great difficulty, by introspection: that the conscious processes of pleasantness and unpleasantness are the same, in whatever mental setting they occur, i.e., with whatever other mental processes they are connected.
PART I CHAPTER II Sensation as a Conscious Element. The Method of investigating sensation § 7. The Definition of Sensation, — We have seen that 'thinking' cannot go on without ideas. When I am thinking about anything, my consciousness consists of a number of ideas, some running their course side by side, and others following these in obedience to the laws of association. We have seen also that we cannot have cer- tain ideas unless the body possesses certain organs; 'mem- ory ' and ' imagination,' e.g., are very largely made up, for most of us, of visual ideas, — and these imply the existence of the eye.
Ideas are always complex, made up of separate parts. Our way of using a single word to express them — though there are good reasons for it — is likely to mislead us upon this matter: it tempts us to think that they are simple and uniform in their nature. Hence it requires some effort and trouble to analyse an idea, even if (as is often the case) it owes its existence to the combined action of sev- eral sense-organs. But every idea can be resolved into elements, i.e., elemental /r^^^.fi'^^/ and these elements are termed sensations.
My idea of a particular book is an idea derived from the co- operation of several bodily organs. It may include at any moment the look of the book (eye), the sound of its contents when read 26 § 7- The Definition of Sensation 27 aloud (ear), its weight (skin, etc.), and the scent of its cover (nose). Now let us leave out of account all the constituents of the idea except those which come from the eye. We have re- maining the red of the leather and gold of the lettering on the cover, and the black and white of the printed pages. Each of these quite simple components of the idea is a se?isation of sight. Or let us leave out of account all the constituents except those coming through the ear. We then have the sounds of a familiar voice, which we imagine to be speaking certain successions of words. Each word uttered has a particular pitch, is a particular musical tone; while at the same time its consonants are heard as noises or auditory shocks. These quite simple processes — the simple tone and the simple noise — are sensatiojis of hearing. Or again: let us leave out of account all the components of the idea except the weight which we remember that the volume has when we hold it up. This weight includes a pressure on the skin of the hand, a pull or strain upon the tendons which hold the muscles of the arm to their bones, and a jamming together of the bones them- selves at wrist and elbow-joint. Each constituent — skin pressure, tendinous strain, articular (joint) pressure — is a quite simple process, which cannot be further analysed. We speak, therefore, oi sejisatio7is of pressure and of strain.
We have now split up the apparently simple ' book ' into a large number of really simple sensations. The analysis was not easy, even though different bodily organs were concerned in the idea: it would be difficult to say, for instance, just what is due, in the idea of 'weight,' to joint, what to sinew, and what to skin. The analysis becomes very much more difficult when all the compo- nents of the idea come from the same sense-organ. Long prac- tice is required before one can analyse the note of a musical instrument into the separate simple tones which it contains. But the analysis is always possible.
We may compare the sensation, the element of the idea, to the elements treated of in chemical science. The idea is a compound; it consists of a number of elemental 28 Sensation as a Conscious Element processes, travelling side by side in consciousness: it therefore resembles the compound bodies analysed in the chemical laboratory. But the sensation resists analysis, just as do the chemical elements oxygen and hydrogen. It stands to the idea as oxygen and hydrogen stand to water. Whatever test we put it to, — however persistent our attempt at analysis and however refined our method of investigation, — we end where we began: the sensation remains precisely what it was before we attacked it. ' Cold,' ' blue,' * salt,' cannot be divided up into any simpler modes of experience.
All sensations come to us from definite bodily organs: cold from the temperature organs in the skin, blue from the sensitive organs in the retina of the eye, salt from sensitive cells planted in the mucous membrane of the tongue. These ' peripheral ' organs — organs at the pe- riphery or on the surface of the body — are united, by nerve-fibres, to the supreme ' central ' organ, the brain. The peripheral organs of temperature are united to one group of cells in the cortex (the grey covering matter) of the hemispheres of the brain; the retina of the eye to another; the peripheral taste-cells to a third. The bodily process with which sensation is connected is, therefore, twofold: it consists of a stimulation of the peripheral organ, and a consequent excitation (carried inwards by nerve-fibres) of the central organ.
Our definition of sensation must take account of its sim- plicity as a conscious process (first part of the problem of psychology: § 4) and of its bodily conditions (third part of the problem). It will run as follows: Sensations are those elemental conscious processes which are connected with bodily processes in definite bodily organs.
§§ 7> S. The Definition and Attributes of Sensation 29 We cannot get any sensation until the peripheral organ has been stimulated. Those unfortunates who are born blind or deaf, who have no peripheral organs which can be stimulated, possess no sensations of sight or hearing at all. It is a mistake to suppose that they live in darkness and silence. To appreciate darkness and silence we must be able to see and hear; darkness is a sen- sation of sight, and silence is in reality a very faint sensation of sound, — the sensation received from the pumping of blood through the arteries of the ear. Those born deaf or blind do not hear or see anything.
But when the peripheral organ has been stimulated some few times, its stimulation ceases to be necessary to the production of a sensation. The central excitation (set up somehow within the brain) is enough. We can ' remember ' a yellow, when our eyes are shut; we can ' imagine ' a cold draught, when our skin is thoroughly warm. The bodily processes connected with the remembered yellow and the imagined cold are central only, not peripheral: but the yellow and the cold, as mental processes, are none the less se7isations.
" They are different from real sensations, however, — different from sensations set up by actual stimulation of the eye and skin," it may be said: " we know that they are only remembered or imagined, and not sensed." That is true: but the difference does not lie in the nature of the processes themselves. A remembered ' yellow ' and a seen ' yellow ' are just the same as sensations, as ' yellows.' If the remembered yellow seems to lack something of the seen yellow, that is only because its intensity is less, its out- line not so distinct, its conscious course more rapid. Really, how- ever, the ^ remembered yellow ' is a more complex process than the seen yellow: it is a yellow plus what we may call the memory- mark. So an imagined cold is a sensation of cold plus the imagi- nation-mark. The processes which make up these marks will be analysed later on (Ch. XI).
§ 8. The Attributes of Sensation. — Although the sensa- tion is an element of mind, that is, a process which can- not be split up into simpler processes, yet it has various 30 Sensation as a Conscious Element aspects or attributes — presents different sides, so to speak — each of which may be separately examined by the psy- chologist. Some sensations have four such aspects; every sensation has at least three. The four are quality, inten- sity, extent and duration. The process is itself, and not some other process (quality); it is stronger or weaker than other sensations (intensity); it spreads over a certain por- tion of space, greater or less (extent); and it lasts a cer- tain, longer or shorter period of time (duration).
Suppose that I have a tuning-fork, which gives the pitch of the concert a. I may strike it gently or roughly. In each case, the * tone ' remains the same, the quality is that of the musical a; but the tone produced by the second blow is louder, more inten- sive, than that produced by the gentle tap. Again: I may let the tone ' run down ' or ' ring off,' or I may stop or ' damp ' it by laying my finger upon the vibrating prongs a second or two after I have struck the fork. The tone is still the same; its duration differs. This tone sensation, then, possesses quality (the pitch of a musical « in a certain octave of the scale), intensity (loudness or softness) and duration (more or less time for the running its course in consciousness). It has no extent, since sounds, though they come to us through space, do not fill space, and therefore cannot be compared as regards size. A bass note, though it may have more ^volume ' (as we say) than a treble note, is not larger than the treble note, in the sense in which the red quality of a peony is larger, more extended than the same quality in a rose.
Had we taken as our illustration this sensation of colour from the eye, or a sensation of pressure upon the skin, we should have found the attribute of extent present in it. No point of coloured light is so small that it has no length or breadth: and no needle- prick is so fine that it does not affect some extent of skin. Extent is an invariable property of visual and cutaneous (skin) sensations.
We may represent a four-attribute sensation in the form indicated by Fig. 2. It must be noted that all the aspects § 8. The Attributes of Sensation 31 (three or four) which a particular sensation can present are, as a matter of fact, always presented together in conscious- ness. If any one of them disappears, the whole sensation disappears with it. A tone which is of no duration, which does not last for any time at all, is not a tone; and a point of light which has no extent cannot give rise to a sensation of sight, — it is just nothing. The quality of a sensation is the attribute which distin- guishes it from every other sensation. And it is quality which makes sensation an elemental conscious process. The fact that one process is stronger or weaker than an- other, lasts a longer or shorter time, is more or less extended, could never tell us whether it was itself sim- ple or complex. But every quality is radically different from every other quality: it always remains itself, through all changes of intensity and of time or space. An a in music may vary in loudness and in duration; but it is still a, and therefore different from all the other tones, b, <:, etc. A blue may show itself as a flash or as a permanent illumination; it may be a point or a broad colour surface: but its blueness differentiates it from all other visual sen- sations. Quality, that is, is the most important and fundamental of the sensation attributes: it constitutes what we might call the core or kernel of the sensation, — though we must not allow the phrase to mislead us, by suggesting that the sensation is a compound process. We might ex- press the fact equally well, perhaps, by saying that sensation intensity is always the intensity of a certain quality; sen- sation duration always the duration of a certain quality, etc.
Quite complex processes may possess their own intensity, dura- tion and extent. Thus a note struck upon the piano, which com- 32 Sensation as a Conscious Element prises several sensations of simple tone, may be spoken of as ' loud ' or * soft '; the taste of a refreshing draught of lemonade may linger in the mouth for a longer or shorter time; and the Sistine Madonna may be imagined as of any size, from that of the origi- nal painting to that of a small cabinet photograph. But no com- plex idea has a single quality. Even if it seems single to the untrained observer, — as the piano note may do, — it can be resolved by practice into its really simple elements (sensation qualities).
How it comes about that a complex process may have a ^ total ' intensity, duration, etc., distinct from the intensities and durations of the sensations composing it, will be explained later on (§§ 39, § 9. The Method of investigating Sensation. — Every science has its own special material to deal with, and consequently its own special methods of working upon that material for the discovery of facts and laws. Physics and chemistry follow * physical ' and * chemical ' methods: and no progress can be made by the student in either sci- ence until he has learned the right way to work, i.e.^ has grasped the significance of method. The special method employed by psychology is that of introspection or self- observation. We ' look into ' the mind, each for himself; or we observe ourselves, — in order to find out what pro- cesses are going on at the time, and how they are influ- encing one another.
This ' looking into ' one's mind or observation of one's own mental processes must not be understood literally, however, as if consciousness were one thing, existing of itself, and the * I,' the observer, could stand apart and watch it from the outside. The * I,' the watching, and the conscious " phenomenon observed, are all alike con- scious processes; so that when *I observe myself,' all that § 9- The Method of Investigating Sensation 33 happens is that a new set of processes is introduced into the consciousness of the moment.
But this introduction of new processes must, it would seem, bring about a change in the particular experience which one sets out to observe. And it is imperative to keep that experience unchanged: a method of observa- tion which involved an alteration of the facts to be ob- served would not be worth much. Direct introspection — observation of a process which is still running its course — is, as a matter of fact, entirely worthless; it defeats its own object.
Suppose, e.g., that I am absorbed in the enjoyment of a humor- ous story or a musical composition, and suddenly (remembering that I am interested in psychology) ask myself what my enjoy- ment is, and what mental processes go to make it up. I find myself baffled: the putting of the question has seriously altered my consciousness. I cannot enjoy and examine my enjoyment at one and the same time.
Psychological introspection, however, does not consist in the effort to follow up a process during its course. The rule for introspection, in the sphere of sensation, is as follows: Be as attentive as possible to the object or process which gives rise to the sensation, and, luhen tJie object is retnove^d or tJie process completed, recall tJie sen- sation by an act of memory as vividly and completely as yon. can.
The object or process which gives rise to a sensation is termed the stimnlns to that sensation. If we attend to the stimulus, the sensation becomes clearer, and has a more enduring place in consciousness than it would have gained in its own right. Hence we can best observe those sensations to whose stimuli we have been especially at- D 34 Sensation as a Conscious Element tentive. We avoid any interference with the workings of consciousness by postponing our observation of the process which we wish to examine until after it has run its full course, and the stimulus which occasioned it has ceased to affect us. We then call it back, look at it from all points of view, and dissect it. Introspective examina- tion must be 2. post mortem examination.
A comparison may help to make the meaning of the rule clear. We may Hken the consciousness upon which the stimulus works to sealing-wax, and the stimulus itself to the signet stone impressed upon it. Attention prepares the mind for the reception of an impression, as the heating of the wax prepares it for the signet; and the more attentive we are to the stimulus, the deeper is the impression which it makes upon us. The impression once made, the wax hardens: we can recall the sensation, scrutinise it, trace the course which it followed, etc., — just as we can hold up the hardened seal to the light, note the pattern, the flaws in the wax, etc., in a way which is impossible during the stage of softness, when the stone produces its greatest effect.
But this introspection, it may well be said, cannot fur- nish very reliable results. The individual can apply the method to one consciousness only — his own; and we all know how easy it is for a single observer to make mis- takes, and how necessary to have more witnesses than one, if a fact is to be securely established. There is no guarantee that other individuals would come to the same conclusion, from an examination of their consciousnesses; and no means of comparing the conclusions reached by different individuals under similar circumstances.
The first objection is unanswerable. But although we can never apply the introspective method to any conscious- ness except our own, we can arrange matters so that other § 9- The Method of Investigating Sensation 35 individuals may be brought forward as witnesses to the facts which we ourselves have observed. This end is attained by the employment of the method under experi- mental conditions.
An experiment is a trial, test, or observation, carefully made under certain special conditions: the object of the conditions being (i) to render it possible for any one who will to repeat the test, in the exact manner in which it was first performed, and (2) to help the observer to rule out disturbing influences during his observation, and so to get at the desired result in a pnre form. If we say precisely how we have worked, other investigators can go through the same processes, and judge whether our conclusion is right or wrong; and if we do the work in a fitting place, with fitting instruments, without hurry or interruption, guarding against any influence which is foreign to the matter in hand, and which might conceivably alter our observation, we may be sure of obtaining 'pure' results, results which follow directly from the conditions laid down by us, and are not due to the operation of any unforeseen or unregulated causes. Experiment thus secures accuracy of observation, and the connection of every result with its own conditions; while it enables observers in all parts of the world to work together upon one and the same psycho- logical problem.
The psychological experiment does not differ in any essential respect from the experiments of the other sciences, — physics, physiology, etc. There is always the one difference already mentioned: while a newly discov- ered insect or a rare mineral can be packed in a box, and sent by one investigator to another in a distant country, the psychologist can never put his consciousness in any 36 Sensation as a Conscious Element similar way at the disposal of his fellow-psychologist. But the difference is a minor difference: it does not ex- tend to the nature and function of the experiment itself, — it does not impair the accuracy of psychological results or prevent community of psychological investigation.
The rule of experimental introspection, in the sphere of sensation, runs as follows: Have yourself placed under such conditions that there is as little likelihood as possible of ex- ternal interference with the test to be made. Attend to the stimulus, and, ivhen it is removed, recall the sensation by an act of memory. Give a verbal account of the processes constituting your consciousness of the stimidus. The ac- count must be written down by the assistant, who has arranged for you the conditions under which the test is to be made. His description of the conditions, and your description of the experience, furnish data from which other psychologists can work.
In whichever form it is employed, the introspective method demands the exercise of memory. Care must therefore be taken to work with memory at its best: the interval of time which elapses between experience and the account of experience must not be so short that memory has not time to recover the experi- ence, or so long that the experience has become faded and blurred. In its experimental form, introspection demands further an exact use of language. The terms chosen to describe the experience must be definite, sharp, and concrete. The conscious process is like a fresco, painted in great sweeps of colour and with all sorts of intermediary and mediating lights and shades: words are little blocks of stone, to be used in the composition of a mosaic. If we are required to represent the fresco by a mosaic, we must see to it that our blocks be of small size and of every obtainable tint and hue. Otherwise, our representation will not come very near to the original.
§ lO. Rides for Introspection of Sensation ^'j Introspection is the sole method by which we can in- vestigate the facts and laws of sensation. It may be used wrongly, as when we try to observe a sensation during its progress; it may be used imperfectly, as when we employ it under varying conditions, or give an incomplete account of our experience, or work at a time when the memory is fatigued; and it may be used rightly, under experimental conditions and safeguards. But, however we use it, it is the sole method which we can follow.
When we pass from the first and second parts to the third part of the problem of psychology (§ 4), — when we ask, not what are the facts and laws of sensation as revealed by introspection, but what are the bodily processes which accompany sensation pro- cesses, — we must, of course, accept the account of the body and its workings which is offered by physiologists and biologists, and which has been obtained by the use of the methods pecuhar to physiology and biology. The union of physiological and psycho- logical methods for psychophysical purposes has led to the formu- lation of a number of ' psychophysical methods.' Since we, as psychologists, are using psychophysics only as means to an end, as an aid to our understanding of mind, it is unnecessary for us to give a full and detailed statement of psychophysical methods in this book. Many of them will be briefly indicated in the Sections in which we enquire into the bodily concomitants of the elemental conscious processes.
§ 10. General Rules for the Introspection of Sensation. — The ' experimental conditions ' which are necessary to render the results of introspection scientifically valuable will, of course, differ in the case of different sensations. The rules which apply in the sense of sight do not hold, without modification, in that of hearing. But there are certain conditions which must always be regarded, in whatever department of sensation we are working: or, to 38 Sensation as a Conscious Element put the matter from the other side, there are certain errors to which we are always hable, and which we must con- stantly guard against (i) When we introspect, we must be absolutely im- partial and unprejudiced. We must not let ourselves be biassed by any preconceived idea. We are likely to think that, in all probability, a certain thing will happen, or we may actually want to obtain a given result, to confirm some view which we have already formed. In either case, we are in danger of mistaken observation. We ought to be ready to take the facts precisely as they are.