The Principles of Psychology, Vols. 1-2

The last point is relative to the theory that what was acquired habit in the ancestor may become congenital tendency in the offspring. So vast a superstructure is raised upon this principle that the paucity of empirical evidence for it has alike been matter of regret to its adherents, and of triumph to its opponents. In Chapter XXVIII we shall see what we may call the whole beggarly array of proof. In the human race, where our opportunities for observation are the most complete, we seem to have no evidence whatever which would support the hypothesis, unless it possibly be the law that city-bred children are more apt to be near-sighted than country children. In the mental world we certainly do not observe that the children of great travellers get their geography lessons with unusual ease, or that a baby whose ancestors have spoken German for thirty generations will, on that account, learn Italian any the less easily from its Italian nurse. But if the considerations we have been led to are true, they explain perfectly well why this law should not be verified in the human race, and why, therefore, in looking for evidence on the subject, we should confine ourselves exclusively to lower animals. In them fixed habit is the essential and

characteristic law of nervous action. The brain grows to the exact modes in which it has been exercised, and the inheritance of these modes — then called instincts — would have in it nothing surprising. But in man the negation of all fixed modes is the essential characteristic. He owes his whole pre-eminence as a reasoner, his whole human quality of intellect, we may say, to the facility with which a given mode of thought in him may suddenly be broken up into elements, which recombine anew. Only at the price of inheriting no settled instinctive tendencies is he able to settle every novel case by the fresh discovery by his reason of novel principles. He is, par excellence^ the educohle animal. If, then, the law that habits are inherited were found exemplified in him, he would, in so far forth, fall short of his human perfections ; and, when we survey the human races, we actually do find that those which are most instinctive at the outset are those which, on the whole, are least educated in the end. An untutored Italian is, to a great extent, a man of the world ; he has instinctive perceptions, tendencies to behavior, reactions, in a word, upon his environment, which the untutored German wholly lacks. If the latter be not drilled, he is apt to be a thoroughly loutish personage ; but, on the other hand, the mere absence in his brain of definite innate tendencies enables him to advance by the development, through education, of his purely reasoned thinking, into complex regions of consciousness that the Italian may probably never approach.

We observe an identical difference between men as a whole and women as a whole. A young woman of twenty reacts with intuitive promptitude and security in all the usual circumstances in which she may be placed.* Her likes * Social and domestic circumstances, that is, not material ones. Perceptions of social relations seem very keen in persons whose dealings with the material world are confined to knowing a few useful objects, principally animals, plants, and weapons. Savages and boors are often as tactful and astute socially as trained diplomatists. In general, it is provable that the consciousness of how one stands with other people occupies a relatively larger and larger part of the mind, the lower one goes in the scale of culture. Woman's intuitions, so fine in the sphere of personal relations, are seldom first-rate in the way of mechanics. All boys teach themselves how a clock goes ; few girls. Hence Dr. Whately's jest, "Woman is the unreasoning animal, and pokes the fire from on top."

and dislikes are formed ; her opinions, to a great extent, the same that they will be through life. Her character is, in fact, finished in its essentials. How inferior to her is a boy of twenty in all these respects ! His character is still gelatinous, uncertain what shape to assume, * trying it on ' in every direction. Feeling his power, yet ignorant of the manner in which he shall express it, he is, when compared with his sister, a being of no definite contour. But this absence of prompt tendency in his brain to set into particular modes is the very condition which insures that it shall ultimately become so much more efficient than the woman's. The very lack of preappointed trains of thought is the ground on which general principles and heads of classification grow up ; and the masculine brain deals with new and complex matter indirectly by means of these, in a manner which the feminine method of direct intuition, admirably and rapidly as it performs within its limits, can vainly hope to cope with.

In looking back over the subject of reasoning, one feels how intimately connected it is with conception ; and one realizes more than ever the deep reach of that principle of selection on which so much stress was laid towards the close of Chapter IX. As the art of reading (after a certain stage in one's education) is the art of skipping, so the art of being wise is the art of knowing what to overlook. The first effect on the mind of growing cultivated is that processes once multiple get to be performed by a single act. Lazarus has called this the progressive * condensation ' of thought. But in the psychological sense it is less a condensation than a loss, a genuine dropping out and throwing overboard of conscious content. Steps really sink from sight. An advanced thinker sees the relations of his topics in such masses and so instantaneously that when he comes to explain to younger minds it is often hard to say which grows the more perplexed, he or the pupil. In every university there are admirable investigators who are notoriously bad lecturers. The reason is that they never spontaneously see the subject in the minute articulate way in which the student needs to have it offered to his slow

reception. They grope for the links, but the links do not come. Bowditch, who translated and annotated Laplace's Mecanique Celeste, said that whenever his author prefaced a proposition by the words ' it is evident,' he knew that many hours of hard study lay before him. When two minds of a high order, interested in kindred subjects, come together, their conversation is chiefly remarkable for the summariness of its allusions and the rapidity of its transitions. Before one of them is half through a sentence the other knows his meaning and replies. Such genial play with such massive materials, such an easy flashing of light over far perspectives, such careless indifference to the dust and apparatus that ordinarily surround the subject and seem to pertain to its essence, make these conversations seem true feasts for gods to a listener who is educated enough to follow them at all. His mental lungs breathe more deeply, in an atmosphere more broad and vast than is their wont. On the other hand, the excessive explicitness and short-windedness of an ordinary man are as wonderful as they are tedious to the man of genius. But we need not go as far as the ways of genius. Ordinary social intercourse will do. There the charm of conversation is in direct proportion to the possibility of abridgment and elision, and in inverse ratio to the need of explicit statement. With old friends a word stands for a whole story or set of opinions. With new-comers everything must be gone over in detail. Some persons have a real mania for completeness, they must express every step. They are the most intolerable of companions, and although their mental energy may in its way be great, they always strike us as weak and second-rate. In short, the essence of plebeianism, that which separates vulgarity from aristocracy, is perhaps less a defect than an excess, the constant need to animadvert upon matters which for the aristocratic temperament do not exist. To ignore, to disdain to consider, to overlook, are the essence of the * gentleman.' Often most provokingly so ; for the things ignored may be of the deepest moral consequence.

But in the very midst of our indignation with the gentleman, we have a consciousness that his preposterous inertia and neg* ativeness in the actual emergency is, somehow or other, ollied with his general superiority to ourselves. It is not only that the gentleman ignores considerations relative to conduct, sordid suspicions, fears, calculations, etc., which the vulgarian is fated to entertain ; it is that he is silent where the vulgarian talks ; that he gives nothing but results where the vulgarian is profuse of reasons ; that he does not explain or apologize ; that he uses one sentence instead of twenty ; and that, in a word, there is an amount of interstitial thinking, so to call it, which it is quite impossible to get him to perform, but which is nearly all that the vulgarian mind performs at all. All this suppression of the secondary leaves the field clear^ — for higher flights, should they choose to come. But even if they never came, what thoughts there were would still manifest the aristocratic type and wear the well-bred form. So great is our sense of harmony and ease in passing from the company of a philistine to that of an aristocratic temperament, that we are almost tempted to deem the falsest views and tastes as held by a man of the world, truer than the truest as held by a common person. In the latter the best ideas are choked, obstructed, and contaminated by the redundancy of their paltry associates. The negative conditions, at least, of an atmosphere and a free outlook are present in the former. I may appear to have strayed from psychological analysis into aesthetic criticism. But the principle of selection is so important that no illustrations seem redundant which may help to show how great is its scope. The upshot of what I say simply is that selection implies rejection as well as choice ; and that the function of ignoring, of mattention, is as vital a factor in mental progress as the function of attention itself.

The reader will not have forgotten, in the jungle of purely inward processes and products through which the last chapters have borne him, that the final result of them all must be some form of bodily activity due to the escape of the central excitement through outgoing nerves. The whole neural organism, it will be remembered, is, physiologically considered, but a machine for converting stimuli into reactions ; and the intellectual part of our life is knit up with but the middle or ' central ' portion of the machine's operations. Let us now turn to consider the final or emergent operations, the bodily activities, and the forms of consciousness connected therewithal.

Every impression which impinges on the incoming nerves produces some discharge down the outgoing ones, whether we be aware of it or not. Using sweeping terms and ignoring exceptions, we might say that every possible feeling prodiujes a movement, and that the movement is a movement of the entire organism, and of each and all its parts. "What happens patently when an explosion or a flash of lightning startles us, or when we are tickled, happens latently with every sensation which we receive. The only reason why we do not feel the startle or tickle in the case of insignificant sensations is partly its very small amount, partly our obtuseness. Professor Bain many years ago gave the name of the Law of Diffusion to this phenomenon of general discharge, and expressed it thus : " According as an impression is accompanied with Feeling, the aroused currents diffuse themselves over the brain, leading to a general agitation of the moving organs, as well as affecting the viscera."

In cases where the feeling is strong the law is too familiar to require proof. As Prof. Bain says : " Each of us knows in our own experience that a sudden shock of feeling is accompanied with movements of the body generally, and with other effects. When no emotion is present, we are quiescent ; a slight feeling is accompanied with slight manifestations ; a more intense shock has a more intense outburst. Every pleasure and every pain, and every mode of emotion, has a definite wave of effects, which our observation makes known to us ; and we apply the knowledge to infer other men's feelings from their outward display. . . . The organs first and prominently affected, in the diffused wave of nervous influence, are the moving members, and of these, by preference, the features of the face (with the ears in animals), whose movements constitute the expression of the countenance. But the influence extends to all the parts of the moving system, voluntary and involuntary ; while an important series of effects are produced on the glands and viscera — the stomach, lungs, heart, kidneys, skin, together with the sexual and mammary organs. . . . The circumstance is seemingly universal, the proof of it does not require a citation of instances in detail ; on the objectors is thrown the burden of adducing unequivocal exceptions to the law." *

There are probably no exceptions to the diffusion of every impression through the nerve-centres. The effect of the wave through the centres may, however, often be to interfere with processes, and to diminish tensions already existing there ; and the outward consequences of such inhibitions may be the arrest of discharges from the inhibited regions and the checking of bodily activities already in process of occurrence. When this happens it probably is like the draining or siphoning of certain channels by currents flowing through others. When, in walking, we suddenly stand still because a sound, sight, smell, or thought catches our attention, something like this occurs. But there are cases of arrest of peripheral activity which depend, not on central inhibition, but on stimulation of centres which discharge outgoing currents of an inhibitory sort. Whenever we are startled, for example, our heart momentarily stops or slows its beating, and then palpitates with accelerated speed. The brief arrest is due to an outgoing current down the pneumogastric nerve. This nerve, when stimulated, stops or slows the heart-beats, and this

particular effect of startling fails to occur if the nerve be cut. In general, however, the stimulating effects of a senseimpression preponderate over the inhibiting effects, so that we may roughly say, as we began by saying, that the wave of discharge produces an activity in all parts of the body. The task of tracing out all the effects of any one incoming sensation has not yet been performed by physiologists. Recent years have, however, begun to enlarge our information ; and although I must refer to special treatises for the full details, I can briefly string together here a number of separate observations which prove the truth of the law of diffusion.

First take effects upon the circulation. Those upon the heart we have just seen. Haller long ago recorded that the blood from an open vein flowed out faster at the beat of a drum.* In Chapter III. (p. 98) we learned how instantaneously, according to Mosso, the circulation in the brain is altered by changes of sensation and of the course of thought. The effect of objects of fear, shame, and anger upon the blood-supply of the skin, especially the skin of the face, are too well known to need remark. Sensations of the higher senses produce, according to Gouty and Charpentier, the most varied effects upon the pulse-rate and blood-pressure in dogs. Fig. 81, a pulse-tracing from these authors, shows the tumultuous effect on a dog's heart of hearing the screams of another dog. The changes of "blood-pressure still occurred when the pneumogastric nerves were cut, showing the vaso-motor effect to be direct and not dependent on the heart. When Mosso invented that simple instrument, the phthysmograph, for recording the fluctuations in volume of the members of the body, what most astonished him, he says, "in the first experiments which he made in Italy, was the extreme unrest of the blood-vessels of the hand, which at every smallest emotion, whether during waking or during sleep, changed their volume in surprising fashion." f Figure 82 (from FereX)

shows the way in which the pulse of one subject was modified by the exhibition of a red light lasting from the moment marked a to that marked h. The effects upon respiration of sudden sensory stimuli are also too well known to need elaborate comment. We * catch our breath ' at every sudden sound. We * liold our breath ' whenever our attention and expectation are strongly Fio. 88.- Respiratory curve of B: a, with eyes open; 6, with eyes closed. engaged, and we sigh when the t<3nsion of the situation is relieved. When a fearful object is before us we pant and cannot deeply inspire ; when the object makes us angry it is, on the contrary, the act of expiration which is hard. I subjoin a couple of figures from Fere which explain them-

selves. Thej show the effects of light upon the breatliing of two of his hysteric patients.* FiQ. 84.— Respiratory curve of L: a, with yellow light; b, with green light; c, with red light. The red has the strongest effect. On the stoeat-glandSf similar consequences of sensorial stimuli are observed. Tarchanoff, testing the condition of the sweat-glands by the power of the skin to start a gal- * Revue Phil., xxiv. pp. 566-7.— For further informatiom about the relations between the brain and respiration, see Danilewsky'a Esaay in the Blologisciies Centralblatt, ii. 690.

vanic current through electrodes applied to its surface, found that " nearly every kind of nervous activity, from the simplest sensations and impressions, to voluntary motions and the highest forms of mental exertion, is accompanied by an increased activity in the glands of the skin." * On the pupil observations are recorded by Sanders which show that a transitory dilatation follows every sensorial stimulus applied during sleep, even if the stimulus be not strong enough to wake the subject up. At the moment of awaking there is a dilatation, even if strong light falls on the eye.t The pupil of children can easily be observed to dilate enormously under the influence of /ear. It is said to dilate in pain and fatigue ; and to contract, on the contrary, in rage.

As regards effects on the abdominal viscera, they unquestionably exist, but very few accurate observations have been made. J The bladder, bowels, and uterus respond to sensations, even indifferent ones. Mosso and Pellicani, in their plethysmographic investigations on the bladder of dogs, found all sorts of sensorial stimuli to produce reflex contractions of this organ, independent of those of the abdominal walls. They call the bladder 'as good an sesthesiometer as the iris,' and refer to the not uncommon reflex effects of psychic stimuli in the human female upon this organ. § M. Fere has registered the contractions of the sphincter ani which even indifferent sensations will produce. In some pregnant women the foetus is felt to move aiter almost every sensorial excitement received by the mother. The only natural explanation is that it is stimulated at such moments by reflex contractions of the womb.|| That the glands are affected in emotion is patent enough in the case of the tears of grief, the dry mouth, moist skin, or diar-

* Quoted from the report of Tarchanoff's paper (in Pfltlger's Archiv, XiiVi. 46) in the American Journal of Psych. , ii. 652. rhoea of fear, the biliary disturbances which sometimes follow upon rage, etc. The watering of the mouth at the sight of succulent food is well known. It is difficult to follow the smaller degrees of all these reflex changes, but it can hardly be doubted that they exist in some degree, even where they cease to be traceable, and that all our sensations have some visceral effects. The sneezing produced by sunshine, the roughening of the skin (gooseflesh) which certain strokings, contacts, and sounds, musical or non-musical, provoke, are facts of the same order as the shuddering and standing up of the hair in fear, only of less degree.

Effects on Voluntary Muscles. Every sensorial stimulus not only sends a special discharge into certain particular muscles dependent on the special nature of the stimulus in question — some of these special discharges we have studied in Chapter XI, others we shall examine under the heads of Instinct and Emotion — but it innervates the muscles generally. M. Fere has given very curious experimental proofs of this. The strength of contraction of the subject's hand was measured by a self -registering dynamometer. Ordinarily the maximum strength, under simple experimental conditions, remains the same from day to day. But if simultaneously with the contraction the subject received a sensorial impression, the contraction was sometimes weakened, but more often increased. This reinforcing effect has received the name of dynamogeny. The dynamogenic value of simple musical notes seems to be proportional to their loudness and height. Where the notes are compounded into sad strains, the muscular strength diminishes. If the strains are gay, it is increased. — The dynamogenic value of colored lights varies with the color. In a subject * whose normal strength was expressed by 23, it became 24 when a blue light was

* The figures given are from an hysterical subject, and the differencei are greater than normal. M. Fere considers that the unstable nervoui system of the hysteric (' ces grenouilles de la psychologie ') shows the law on a quantitatively exaggerated scale, without altering the qualitative relations. The effects remind us a little of the influence of sensations upott minimal sensations of other orders discovered by Urbantschitsch, and w- ported on page 29 of this volume.

thrown on the eyes, 28 for green, 30 for yellow, 35 for orange, and 42 for red. Red is thus the most exciting color. Among tastes^ sweet has the lowest value, next comes salt, then bitter, and finally sour, though, as M. Fere remarks, such a sour as acetic acid excites the nerves of pain and smell as well as of taste. The stimulating effects of tobaccosmoke, alcohol, beef-extract (which is innutritions), etc., etc., may be partly due to a dynamogenic action of this sort. — Of odors, that of musk seems to have a peculiar dynamogenie power. Fig. 85 is a copy of one of M. Fere's d3^namographic tracings, which explains itself. The smaller contractions are those without stimulus ; the stronger ones are due to the influence of red rays of light.

Everyone is familiar with the patellar reflex, or jerk upwards of the foot, which is produced by smartly tapping the tendon below the knee-pan when the leg hangs over the other knee. Drs. Weir Mitchell and Lombard have found that when other sensations come in simultaneously with the tap, the jerk is increased.* Heat, cold, pricking, itching, or faradic stimulation of the skin, sometimes strong optical impressions, music, all have this dynamogenic effect, which also results whenever voluntary movements are set up in other parts of the body, simultaneously with the tap.t

f Prof. H. P. Bowditch has made the interesting discovery that if the reinforcing movement be as much as 0.4 of a second late, the reinforcement fails to occur, and is transformed into a positive inhibition of the knee-jerk for retardations of between 0.4' and 1.7'. The knee-jerk fails to be modified at all by voluntary movements made later than 1 .7' after the patellar ligament is tapped (see Boston Med. and Surg. Journ., May 31 , simply reinforces another already under way, must not be confounded with reflex acts properly so called, in which new activities are originated by the stimulus. All instinctive performances and manifestations of emotion are reflex acts. But underneath those of which we are conscious there seem to go on continually others smaller in amount, which probably in most persons might be called fluctuations of muscular tone, but which in certain neurotic subjects can be demonstrated ocularly. M. Fere figures some of them in the article to which I have already referred.^

Looking back over all these facts, it is hard to doubt the truth of the law of diffusion, even where verification is beyond reach. A process set up anywhere in the centres reverberates everywhere, and in some way or other affects the organism throughout, making its activities either greater or less. We are brought again to the assimilation which was expressed on a previous page of the nerve-central mass to a good conductor charged with electricity, of which the tension cannot be changed anywhere without changing it everywhere.

Herr Schneider has tried to show, by an ingenious and suggestive zoological review,t that all the special movements which highly evolved animals make are differentiated from the two originally simple movements, of contraction and expansion, in which the entire body of simple organisms takes part. The tendency to contract is the source of all the self-protective impulses and reactions which are later developed, including that of flight. The tendency to expand splits up, on the contrary, into the impulses and instincts of an aggressive kind, feeding, fighting, sexual intercourse, etc. Schneider's articles are well worth reading, if only for the careful observations on animals which they embody. I cite them here as a sort of evolutionary reason to add to the mechanical a priori reason why there ought to be the diffusive wave which our a posteriori instances have shown to exist.

portant classes of movement consequent upon cerebromental change. They may be enumerated as — Instinct is usually defined as tJwfacvlty of acting in such a way as to prodvxie certain ends, without foresight of the ends, and without previous education in the performance. That instincts, as thus defined, exist on an enormous scale in the animal kingdom needs no proof. They are the functional correlatives of structure. With the presence of a certain organ goes, one may say, almost always a native aptitude for its use.

" Has the bird a gland for the secretion of oil ? She knows instinctively how to press the oil from the gland, and apply it to the feather. Has the rattlesnake the grooved tooth and gland of poison ? He knows without instruction how to make both structure and function most effective against his enemies. Has the silkworm the function of secreting the fluid silk ? At the proper time she winds the cocoon such as she has never seen, as thousands before have done ; and thus without instruction, pattern, or experience, forms a safe abode for herself in the period of transformation. Has the hawk talons ? She knows by instinct how to wield them effectively against the helpless quarry, "f

A very common way of talking about these admirably definite tendencies to act is by naming abstractly the purpose they subserve, such as self-preservation, or defence, or care for eggs and young — and saying the animal has an instinctive fear of death or love of life, or that she has an instinct of self-preservation, or an instinct of maternity and the like. But this represents the animal as obeying abstractions which not once in a million cases is it possible it can have framed. The strict physiological way of interpret-

* This chapter has already appeared (almost exactly as now printed) in the form of magazine articles in Scribner's Magazine and in the Popular Science Monthly for 1887. ing the facts leads to far clearer results. The actions tve caM instinctive oil conform to the general reflex type ; they are called forth by determinate sensory stimuli in contact with the animal's body, or at a distance in his environment. The cat runs after the mouse, runs or shows fight before the dog, avoids falling from walls and trees, shuns fire and water, etc., not because he has any notion either of life or of death, or of self, or of preservation. He has probably attained to no one of these conceptions in such a way as to react definitely upon it. He acts in each case separately, and simply because he cannot help it ; being so framed that when that particular running thing called a mouse appears in his field of vision he must pursue ; that when that particular barking and obstreperous thing called a dog appears there he must retire, if at a distance, and scratch if close by ; that he must withdraw his feet from water and his face from flame, etc. His nervous system is to a great extent a preorganized bundle of such reactions — they are as fatal as sneezing, and as exactly correlated to their special excitants as it is to its own. Although the naturalist may, for his own convenience, class these reactions under general heads, he must not forget that in the animal it is a particular sensation or perception or image which calls them forth.

At first this view astounds us by the enormous number of special adjustments it supposes animals to possess readymade in anticipation of the outer things among which they are to dwell. Can mutual dependence be so intricate and go so far? Is each thing born fitted to particular other things, and to them exclusively, as locks are fitted to their keys ? Undoubtedly this must be believed to be so. Each nook and cranny of creation, down to our very skin and entrails, has its living inhabitants, with organs suited to the place, to devour and digest the food it harbors and to meet the dangers it conceals ; and the minuteness of adaptation thus shown in the way of structure knows no bounds. Even so are there no bounds to the minuteness of adaptation in the way of conduct which the several inhabitants display.