§ 6y. Theory of Weber's Law. — Every sense-organ, we said in § 64, offers a certain amount of frictional resistance to stimulus; it is this resistance that explains the fact of the stimulus limen. There can be no doubt that the dif- ferential limen is a fact of the same order, to be explained in the same way. Whatever the present state of the sense-organ may be, whatever excitatory processes are already in progress within it and within the connected parts of the central nervous system, the same sort of re- sistance is offered to an incoming stimulus. When the nervous machine has once been started, it will continue to work, without interruption, so long as adequate stimulation is continued: or, in other words, when sensation has once been set up, it will follow, continuously, the changes of stimulus. But if the stimulus cease for a moment to act, 222 The Intensity of Sensation the machine becomes inert, and must be started up again as if it had completely run down.
Intrinsically, therefore, the relation between sense-dis- tance and stimulus-difference, which is expressed in Weber's Law, is a continuous relation; intensity of sen- sation is a continuous function of intensity of stimulus. In this sense, Weber's Law explains the facts of sensible intensity just as Hering's theory of vision or Helmholtz' theory of audition explains the facts of sensible quality. Weber's Law is itself the theory of sensible intensity. But the continuous function is changed, under certain con- ditions, into a discontinuous function; we have to explain the limens. And we explain them, stimulus limen and differential limen alike, by reference to the inertia of the nervous mechanism.
An illustration may help to make things clearer. If a magnetic needle is suspended at the centre of a circular coil of wire, and an electric current is sent through the wire, the needle is deflected from its position of rest. The angle of deflection is, however, not directly proportional to the strength of current. As the strength of current is increased, by equal amounts, the deflection of the needle becomes progressively smaller and smaller. The mathe- matical expression of the relation is very simple. If a is the num- ber of amperes in the current, k a constant, and 0 the angle of deflection, then a = k tan 6. — Here is an expression that is very like the S = c log R of Weber's Law; and both formulas are the expression of a continuous function.
Now suppose that the needle is hanging steady, whether at the zero-point of its scale or at any other point at which it is held by the current in the coil, and that we increase the current very slowly. At first we get no movement at all. Presently, however, when the current has been increased by a certain amount, the needle goes with a little jump to the position which the formula requires. In this case, we have two phenomena before us. On § 6y. Theory of Weber s Law 223 the one hand, the needle is a magnetic needle, and the amount of its deflection is a continuous function of the current in the coil. On the other hand, the needle does not move, from any position of rest, without friction; so that under the conditions of our second experiment we observe, not a continuous movement, but a series of jerks. In just the same way, we have for intensity of sensation the continuous function expressed in Weber's Law; but we also have the stimulus and the differential limens as facts of friction. — From the point of view of experimental psychology, Weber's Law has a very special significance, as summing up the results of the first successful attempt at mental measurement (§ 63). At the present time, methods of measurement, — metric methods, as they are technically called, — have been employed in many other fields of the mental life. Indeed, while little has been done in comparison with what still remains to do, there is no doubt that, in principle, every single problem that can now be set in psycho- logy may be set in quantitative form. The psychological text- books of the next century will be as full of formulas as the text- books of physics are to-day.
The Law is also of great importance in our daily life, since wherever it is valid we are governed, not by the differences, but by the quotients of the intensive stimuli that affect us. It is be- cause Weber's Law holds for a middle range of light-intensities that we are able to ignore the manifold changes of illumination to which we are exposed in the course of the daylight hours. It is for the same reason that the painter, who cannot at all reproduce by his pigments the absolute intensities of light in nature, can nevertheless furnish a recognisably true copy of any natural scene. And again, it is because Weber's Law holds for a middle range of sound-intensities that a large block of seats in the concert-room, at a moderate distance from the stage, can all be sold at the same prices and all have equal advantages for hearing.
224 The Intensity of Sensation References for Further Reading §§ 62-67. A general account of the problems of mental measurement is given in the author's Experimental Psychology, II., i., 1905, Intro- duction; and an historical sketch of the course of experiment, ibid., II., Li., 1905, Introduction: The Rise and Progress of Quantitative Psy- chology. References of especial importance are: E. H. Weber, Der Tastsinn und das Gemeingefuhl, an article in R. Wagner's Haudwort- er bitch der Physiologie, iii., 2, 1846, 481 (also published separately, 1849, '851); G. T. P-^echner, Elemente der Psychophysik, 2 vols., i860 (1889, 1907), esp. i., chs. vi.-x.; G. E. Miiller, Zur Grundlegung der Psychophysik, 1878; Die Gesichtspunkte und die Tatsachen der psycho- physischen Methodik, 1904 (also in L. Asher and K. Spiro, Ergebnisse der Physiologie, II., ii., 266); J. Delboeuf, Elements de psychophysique generate et speciale, 1883; Examen critique de la loi psychophysique, sa base et sa signification, 1883; H. Ebbinghaus, Ueber negative Empfin- dungswerte, Zeitschrift f Psychologie u. Physiologie d. Sinnesorgane, i., 1890, 320, 463; W. Wundt, Grundziige d. physiologischen Psychologie, AFFECTION AFFECTION § 68. Feeling and Affection. — The word 'feeling' is used in a great variety of meanings. A thing feels rough or smooth, hard or soft, sharp or blunt, firm or shaky, warm or cold, elastic or brittle, thick or thin, clammy or oily. We ourselves feel hungry or thirsty, fresh or tired, ener- getic or lazy, strong or weak, well or ill. We also feel com- fortable or uncomfortable, we feel at home or strange, at ease or ill at ease, natural or constrained; we feel happy, cheerful, restless, angry, irritable, eager, calm. We feel hopeful, despondent, grieved, hurt, injured, relieved, con- tented, gloomy, anxious, annoyed. We feel indifferent, and we feel sympathetic; we feel the difficulty of an objec- tion, the truth of an argument, the nobility of a character, the sacredness of a belief. 'Feel' and 'feeling' seem, indeed, to be psychological maids of all work; they can do, in the sentence, practically anything that a verb and a sub- stantive can be called upon to do. There is little hope, one would think, of turning them to strict psychological ac- count, and of giving them a place in a list of technical terms.
Let us see what happens, however, if we contrast feeling with sensation. Suppose that I say to you: The organ- ism not only senses, but also feels; consciousness is made up, not of sensations alone, but of sensations and feel- ings. Here, surely, there is a hint or suggestion, vague though it may be, of the true psychological meaning of 226 Affection ' feel ' and ' feeling.' You realise that stimuli do something more than arouse sensation; they give rise to processes of a different kind, to 'feelings' in a special sense; we do not merely take the impressions as they come, but we are affected by them, we feel them; and what we feel is their agreeableness or disagreeableness, their pleasantness or unpleasantness. Colours and tones, tastes and smells, may be pleasing or unpleasing just as obviously and just as directly as they are red or c, bitter or musky; and their pleasant or unpleasant character is a matter of feeling.
We have gained something, then, by contrasting feeling with sensation; we have found a fairly definite meaning for the term, and we have marked off a new field of mind for further study. At this point, unfortunately, the views of modern psychologists begin to differ; the psychology of feeling is still, in large measure, a psychology of personal opinion and belief. The writer holds that there is an ele- mentary affective process, a feeling-element, which in our own minds is coordinate with sensation and distinguishable from it, but which is nevertheless akin to sensation and is derived from the same source, made (so to speak) out of the same kind of primitive mental material: this elemen- tary process is termed affection. He holds, further, that there are only two kinds or qualities of affection, pleasant- ness and unpleasantness. The principal reasons for and against this view are set forth in the following sections.
If we look carefully at a list of ' feelings,' such as that given at the beginning of this § 68, we find that the experiences in question fall into three main groups. We have, in the first place, certain perceptions of touch: hardness, roughness, solidity, etc. We have, secondly, certain complexes of organic sensations: hunger, § 68. Feeling and Affection 227 fatigue, etc. And we have, thirdly, a number of mental processes which differ markedly in various ways, but which are all character- ised by the predominance of pleasantness or unpleasantness: joy, sorrow, anger, difficulty, etc.
In ordinary speech, we oppose ' feeling ' to ' intellect'; the man who is swayed by feeling is contrasted with the man who acts coolly and deliberately, by reasoned judgment. This use of the term is so natural and so habitual that we shall do well to keep it in psychology. ' Feeling ' will then be the general name for all sorts of pleasant-unpleasant experience, for every form of emotion, mood, sentiment and passion. All the items in the third division of our list will be rightly called feelings.
But ' feeling ' is also used, in psychology, in a narrower and more technical sense. It denotes a simple connection of sensa- tion and affection, in which the affection preponderates. Hunger, for instance, is a sensation. But we may speak of a feeling of hunger if we mean a jolly hunger or a gnawing hunger; if, that is, we mean a pleasantly stimulating or an unpleasantly insistent hunger. Pain, again, is a sensation; and it is a sensation that, at different intensities and under different circumstances, may be pleasant, indifferent, or unpleasant. Usually it is unpleasant, and strongly unpleasant. When this is the case, we speak in psy- chology of a feeling of pain. And in just the same way we may speak of a feeling of fatigue, of nausea, of drowsiness, of freshness, of bodily strength. All the items in the second division of our list are rightly called feelings, in this narrower meaning of the term, provided that the sense-quality is accompanied by an inten- sive affection, pleasant or unpleasant. They are feelings proper, or sense-feelings.
The items of the first division are not feelings at all, but perceptions; and they are termed perceptions, as well as feelings, in the language of everyday life. In their case, psychology has no choice; the name ' feelings ' must be given up. We shall, however, have something further to say about them in § 69. — In summary, then, we have the following terms. Affection is an elementary mental process. Affection is the characteristic ele- ment in emotion, in love and hate, joy and sorrow, just as sensa- 228 Affection tion is the characteristic element in perception, and image the characteristic element in idea (§ 10). Feeling in the narrower meaning of the word, sense-feeling, is a simple connection of affec- tion and sensation, in which the affective element predominates: in this sense we are said to feel sleepy, tired, hungry, rested. Feeling, in the wider meaning of the word, is the general name for the affective side of our mental life: in this sense we are said to feel glad or sorry, worried or hopeful, proud or ashamed. There is no reason why the two meanings of ' feeling ' should lead to confusion, and we shall be careful not to confuse them in this book.
§ 69. Affection and Sensation. — We have now to enquire into the nature of affection, considered as an element of mind; to ask how it resembles and how it differs from sensation. We will take the resemblances first.
Sensation was denned, in § 12, as an elementary mental process which is constituted of at least four attributes, — quality, intensity, clearness and duration. Now affection has three of these attributes, — quality, intensity, and duration; it thus appears as a process of the same general kind as sensation, and it may be defined on the same lines, by reference to attributes which are common to both. Affection has qualities: it has at least the two qualities of pleasantness and unpleasantness, and (as we shall see in § 72) some psychologists believe that it has many more. Affection shows differences of intensity: an experience may be mildly pleasant, slightly disagreeable, or wonder- fully pleasant, unbearably disagreeable. And affection shows differences of duration: pleasure may be momentary, or may persist as a permanent mood; and unpleasantness behaves in the same way. So far, then, there is a general resemblance between affection and sensation.
Again: we have seen that certain sensations show the § 6g. Affection and Sensation 229 phenomenon of adaptation. In many departments of sense — in pressure, in temperature, in smell, in taste — a sensa- tion may disappear, fade out of consciousness, if the stimu- lus is continued. Sight, too, obeys the law of adaptation. We do not, it is true, become blind under visual stimula- tion; but our vision is reduced to a neutral grey, the quality of the persistent central excitation (§ 18). Pre- cisely the same phenomenon of adaptation appears in the case of affection. If we are exposed for a long time together to the same stimulus, we may cease to be affected by it at all. The cookery of a foreign country is, when we first make acquaintance with it, distinctly pleasant or unpleasant; but in either case it quickly becomes indiffer- ent. Dwellers in the country do not find the pleasure in country sights and odours that the townsman does; they have grown used to their surroundings. The whir of a sewing machine in the room above that in which we are working may at first be extremely annoying; but as we become accustomed to it, its unpleasantness disappears. There is, indeed, no region of mind in which this law of affective adaptation fails to manifest itself. During the first few weeks of our stay in a beautiful neighbourhood we may be continually delighted with.the colours and forms of the landscape. But we soon grow indifferent to them: fields and hills and streams are seen as clearly as ever, but they have ceased to excite pleasure. On the other hand, a piece of vulgarity which at first offends us may be taken as a matter of course if constantly repeated among those in whose company we are thrown. Here is a second point of likeness between affection and sensation.
The fact of affective adaptation seems to show as clearly, in these instances, as the fact of olfactory adaptation showed in the 230 Affection instances of § 32. Nevertheless, it has been disputed; some psychologists explain the phenomena in terms of sensory adapta- tion. It is, they say, the cookery and the landscape that we grow accustomed to, not the disagreeableness of the dishes and the beauty of the landscape. There are, that is, as many possibilities of sensory adaptation as there are attributes of sensation; we may become adapted to intensity and clearness and duration, precisely as we become adapted to quality. If a friend asks us: " Doesn't that sewing machine annoy you? " we shall be likely to reply: " No! it would if I heard it, but I simply don't bear it any more." And the answer, these psychologists say, is correct; we have become adapted, not to the quality of the noise, but to its intensity and clearness; we have ceased to attend to it; it is no longer effective as a stimulus, and so its original disagreeableness has naturally lapsed. We have grown used, not to the disturbance, but to the noise; and the noise is now, as a result of our adapta- tion, both weak and obscure.
In the case of the sewing machine, this explanation is possible. But it is not convincing; for we may very well have become adapted both to the sensation and to the affection; the two adap- tations may have gone along side by side. And in other cases, in which the stimulus is not continuous but intermittent (mealtimes, country walks, the behaviour of acquaintances), affective adapta- tion seems obvious. I may be keenly aware of the odour of garlic, and yet be entirely indifferent to it. I may take sharp note of the fact that the person with whom I am talking begins to use his toothpick, and yet have no feeling of disgust. We shall see, in § 78, that it is possible to attend without feeling; and if it is, if the sensation that fills the chief place in consciousness may be indifferent, then affective adaptation is certain. The objection shows, however, — what we have already insisted on, — that it is hardly possible to take a single step in the psychology of feeling without meeting contradiction and conflict of opinion.
Thirdly, the processes of pleasantness and unpleasant- ness show a strong introspective resemblance to organic sensations. Pleasantness seems akin to health, drowsiness, § 6g. Affection and Sensation 231 bodily comfort, repletion; unpleasantness seems akin to pain, bodily discomfort, over-fatigue, lassitude. No doubt these experiences, as they present themselves in everyday life, are more than sensations; they are sense-feelings, complexes of affection and sensation; the total conscious experience that we call health, for instance, contains a pleasant affection along with various, kinaesthetic and other, sensory processes. Still, if we analyse repletion or fatigue, and so far as possible set off the affective element from the constituent sensations, the resemblance appears to persist. Affection is like organic sensation in much the same sense in which sensations of taste are like sensations of smell (§§ 29, 36).
In fine, affection resembles sensation in the nature of its attributes and in its behaviour when a stimulus is long continued, while the qualities of affection, pleasantness and unpleasantness, show an intrinsic likeness to the qualities of organic sensation. What, now, are the differ- ences?
The first difference is this: that affection lacks the attri- bute of clearness. Pleasantness and unpleasantness may be intensive and lasting, but they are never clear. This means, if we put it in the language of popular psychology, that it is impossible to attend to an affection. The more closely we attend to a sensation, the clearer does it be- come, and the longer and more accurately do we remem- ber it. But we cannot attend to an affection at all; if we attempt to do so, the pleasantness or unpleasantness at once eludes us and disappears, and we find ourselves con- templating some obtrusive sensation or image which we had no desire to observe. If we want to get pleasure from a concert or a picture, we must attend to what we hear 232 Affection and what we see; so soon as we try to attend to the pleasure itself, the pleasure is gone.
The lack of the attribute of clearness is sufficient, in itself, to differentiate affection from sensation; a process that cannot be made the object of attention is radically different, and must play a radically different part in con- sciousness, from a process which is held and enhanced by attention. And it should be noted that lack of clearness distinguishes affection from organic sensation as definitely as from sensations of sight or hearing; we have no diffi- culty in attending to the sensory components of hunger and thirst and fatigue.
There is, however, a further difference. Pleasantness and unpleasantness are, what their names imply them to be, opposites. The opposition is not a matter of contrast, as this term is used in the psychology of sensation, al- though it is often referred to as contrast: it is rather a matter of incompatibility in consciousness. There is no similar opposition of sensory qualities.
It was said in § 26 that tones are intrinsically harmonious, colours intrinsically antagonistic. This statement means that the nervous processes underlying visual sensation are antagonistic, and that colours themselves offset one another, show one another up; whereas the nervous processes aroused by the sympathetic vibra- tion of the basilar fibres are confluent, synergic, and tones them- selves show a tendency to blend or fuse with one another. It must, however, be understood that the antagonism of visual sensa- tions is not at all the same thing as the incompatibility of pleasant- ness and unpleasantness: for, first, the antagonistic qualities of black and white are actually connected by the series of greys, due to the admixture of the central grey; and we might, with similar aid from the centre, obtain series of sense-qualities connecting R with G, and B with K Pleasantness, on the other hand, is con- § 6g. Affection and Sensation 233 sciously at odds with unpleasantness; the opposition of the two processes belongs to the essence of them as experienced. And secondly, there is no such thing as affective contrast, in the strict meaning of the term; the pleasure of convalescence is not en- hanced by the unpleasantness of past suffering, as red is enhanced by green. Convalescent comfort is itself the opposite, the con- scious antithesis, of the discomfort of sickness; but it is not in- fluenced by that discomfort.
It is true, however, that we often speak loosely of contrast when we are referring to affective opposition. An ordinary man, seen by the side of a dwarf, looks unusually large; the same man, seen by the side of a giant, looks unusually small. We say that he looks large and small by contrast. The fact is that we feel a sort of contemptuous pity for the dwarf, and a surprised admiration for the man beside him; and again, a contempt for the man and an admiration for the giant. What we have laid to the account of a spatial contrast is really due to affective opposition. — It is worth noting that this affective opposition is reflected in certain of the cutaneous perceptions that in ordinary speech are termed feelings (§ 68). We oppose warmth and cold, — not as sensory qualities, for they belong to different senses; but as pleasant and unpleasant. On the whole and in general, warm and smooth and soft things are pleasant to the touch, and cold and rough and hard things are unpleasant. Indeed, whenever we find in consciousness an opposition of this sort, we may be sure that it is an opposition due to the presence of affective processes along- side of the sensations. And in so far as we oppose warmth to cold, smoothness to roughness, for affective reasons, in so far there is some justification for giving these processes the name of feel- ings.
Other Distinguishing Characters of Affection. — We have dis- tinguished affection from sensation on the negative ground of lack of clearness, and on the positive ground of qualitative opposition. It has been urged, further, that sensations are the objective and affections the subjective elements of consciousness. No one, however, has found a satisfactory psychological definition of these terms. We may, perhaps, call sensations objective in the sense 234 Affection 234 Affection that they can stand alone in consciousness, independently of affec- tion; and we may call affections subjective in the sense that they never appear alone, but always and of necessity as the companions of sensation. But this is itself a disputed point. Again, it is urged that all sensations may be localised in space, while affection is not localisable. But it is argued, on the other side, that tones and odours sometimes resist all our efforts to place them; while the pleasantness of a sweet taste, and the unpleasantness of an organic pain, are localised along with the taste and the pain themselves. Yet again, it is urged that the sensation is nor- mally more intensive than the image, the perception than the idea; but that the affection which accompanies the idea is nor- mally more intensive than that which accompanies the perception. But, if one psychologist informs us that " only the very highest degrees of sensory agreeableness and sensory disagreeableness are now able to overpower the 'higher' feelings," another asserts, just as positively, that " ideal pains and pleasures are not com- parable in mere intensity with sensuous pains and pleasures." Contradiction could hardly be flatter!
In all these controversies, the writer leans to the affirmative side, the side which affirms a difference between affection and sensation. He does not believe, for instance, that a purely af- fective process may enter consciousness alone, as the herald of a coming sensory process, or that it may lag behind in consciousness alone, after its sensory companions have disappeared, — although both these statements are freely made. Pie finds a sort of flimsi- ness or softness or yieldingness in the texture of pleasantness and unpleasantness; their quality is like that of certain organic sensa- tions, but they are less hard, less stable, less self-supporting. This difference, which is difficult to express in words, is probably con- nected with the presence or absence of the attribute of clearness; but there is no reason why it should not be termed a difference of objective and subjective. Again, the writer believes that affec- tions are always coextensive with consciousness, diffused over all the sensory contents present at the time; and that, if the pleasantness of a taste is localised in the mouth, that is simply because con- sciousness itself, under the experimental conditions, has been § 6g. Affection and Sensation 235 narrowed down to a taste-consciousness. Finally, there seems to be no doubt that, in the adult human mind, the ideal feelings are usually stronger than the sensuous. I fall down on a slippery path, and hurt myself; but my first thought is " How stupid of me to slip! " I sit in a draughty concert hall with the certainty of a neuralgia; but I am afraid of making myself ridiculous, and so I remain in my chair. It is a raw evening, and I have a little cold; but I go to see my friend, because I do not want to disappoint him. Were it worth while, illustrations of this kind could be multiplied a hundredfold. It is not worth while, because the question at issue cannot be decided by casual observation. Di- vergence of opinion is inevitable, until the experimental method has been brought to bear, systematically, upon the problems of feeling. In the meantime, we must be content to mark off affec- tion from sensation by the two salient characters described in the text.
The Question of Mixed Feelings. — It would seem that, if pleasantness and unpleasantness are opposite and incompatible, they cannot coexist in the same consciousness, — that we cannot feel pleased and feel displeased at one and the same moment. A consciousness, however, is a very complicated affair; it is made up of a large number of elementary processes; and there is no doubt that the nervous system may be exposed, in different quarters, to stimuli some of which, if felt by themselves, would be felt pleasantly and some of which, if felt alone, would be felt unpleasantly. Hence it becomes a question of fact whether these various stimuli, acting together at the same time, give rise to a single resultant affection, either pleasant or unpleasant; or whether every stimulus sets up its own localised affection, so that consciousness may be a mosaic of separate pleasantnesses and unpleasantnesses.
Language favours the second alternative. We go back to school after the holidays with mixed feelings; we visit our old home, after a long absence, with mixed feelings; there is, indeed, hardly anything that we may not look upon, or look back or forward to, with mixed feelings. Juliet tells us that parting is sweet sorrow, a pleasant unpleasantness; and Tennyson's Geraint watches the 236 Affection mowers, whose dinner he has just eaten, with humorous ruth, that is, with a pleasantly unpleasant feeling. There is no pleasure, we are told, without its alloy of pain; there is no despair so dark that it is not lightened by a ray of hope. Popular psychology makes no question about mixed feelings; and a psychologist of standing writes that " almost all mental states which are marked by strong feeling in the case of developed minds are mixed feelings."
On the other hand we know that a single trifling annoyance may colour our whole mood. When Othello behaves unkindly to Desdemona, she excuses him on the ground that he is worried by affairs of state; "for let our finger ache," she says, "and it indues our other healthful members ev'n to that sense of pain." We know, too, that if we are in a particularly good temper we 'take everything good-temperedly; we may even ask pardon of the man who has trodden on our corns. And there is really no proof that the pleasantness and unpleasantness of the mixed feeling are strictly coincident: Juliet may be alternately glad and sorry; sorry now to part from Romeo, but glad the next moment that he is there, as her lover, to be parted from, and glad a moment after in the thought of seeing him again. How quickly the pendulum of feeling may swing we see in the case of the child, who is crying bitterly at its hurt and then, within a few seconds, is smiling over a lump of sugar.
The final appeal lies, of course, to experiment. Unfortunately, but few experiments have so far been made, and the results of these few are not wholly clear. It is safe to say, however, that the tendency of the experimental evidence is decidedly negative; mixed feelings are, in the laboratory, the exception and not the rule; and the exceptional cases are themselves not above sus- picion. The writer has never found, in his own experience, a definite and unmistakable case of mixed feeling.
§ 70. Other Views of Affection. — Affection, as we have described it, is an elementary mental process that is both like and unlike sensation. The resemblance is so great that the two processes are evidently derived from a com- § 7°- Other Views of Affection 237 mon mental ancestor; the difference is so great that we have no choice but to rank affection, in human psychology, as a second type of mental element, distinct from sensa- tion.