In the case of the higher thought activities, it is not probable that one section of the frontal lobes of the cortex is set apart for thinking, one for feeling, and one for willing, etc., but rather that the whole frontal part of the cortex is concerned in each. In the motor and sensory areas, however, the case is different; for here a still further division of labor occurs. For example, in the motor region one small area seems connected with movements of the head, one with the arm, one with the leg, one with the face, and another with the organs of speech; likewise in the sensory region, one area is devoted to vision, one to hearing, one to taste and smell, and one to touch, etc. We must bear in mind, however, that these regions are not mapped out as accurately as are the boundaries of our states—that no part of the brain is restricted wholly to either sensory or motor nerves, and that no part works by itself independently of the rest of the brain. We name a tract from the predominance of nerves which end there, or from the chief functions which the area performs. The motor localization seems to be the most perfect. Indeed, experimentation on the brains of monkeys has been successful in mapping out motor areas so accurately that such small centers as those connected with the bending of one particular leg or the flexing of a thumb have been located. Yet each area of the cortex is so connected with every other area by the millions of association fibers that the whole brain is capable of working together as a unit, thus unifying and harmonizing our thoughts, emotions, and acts.

6. FORMS OF SENSORY STIMULI

Let us next inquire how this mechanism of the nervous system is acted upon in such a way as to give us sensations. In order to understand this, we must first know that all forms of matter are composed of minute atoms which are in constant motion, and by imparting this motion to the air or the ether which surrounds them, are constantly radiating energy in the form of minute waves throughout space. These waves, or radiations, are incredibly rapid in some instances and rather slow in others. In sending out its energy in the form of these waves, the physical world is doing its part to permit us to form its acquaintance. The end-organs of the sensory nerves must meet this advance half-way, and be so constructed as to be affected by the different forms of energy which are constantly beating upon them.



THE END-ORGANS AND THEIR RESPONSE TO STIMULI.—Thus the radiations of ether from the sun, our chief source of light, are so rapid that billions of them enter the eye in a second of time, and the retina is of such a nature that its nerve cells are thrown into activity by these waves; the impulse is carried over the optic nerve to the occipital lobe of the cortex, and the sensation of sight is the result. The different colors also, from the red of the spectrum to the violet, are the result of different vibration rates in the waves of ether which strike the retina; and in order to perceive color, the retina must be able to respond to the particular vibration rate which represents each color. Likewise in the sense of touch the end-organs are fitted to respond to very rapid vibrations, and it is possible that the different qualities of touch are produced by different vibration rates in the atoms of the object we are touching. When we reach the ear, we have the organ which responds to the lowest vibration rate of all, for we can detect a sound made by an object which is vibrating from twenty to thirty times a second. The highest vibration rate which will affect the ear is some forty thousand per second.

Thus it is seen that there are great gaps in the different rates to which our senses are fitted to respond—a sudden drop from billions in the case of the eye to millions in touch, and to thousands or even tens in hearing. This makes one wonder whether there are not many things in nature which man has never discovered simply because he has not the sense mechanism enabling him to become conscious of their existence. There are undoubtedly "more things in heaven and earth than are dreamt of in our philosophy."

DEPENDENCE OF THE MIND ON THE SENSES.—Only as the senses bring in the material, has the mind anything with which to build. Thus have the senses to act as messengers between the great outside world and the brain; to be the servants who shall stand at the doorways of the body—the eyes, the ears, the finger tips—each ready to receive its particular kind of impulse from nature and send it along the right path to the part of the cortex where it belongs, so that the mind can say, "A sight," "A sound," or "A touch." Thus does the mind come to know the universe of the senses. Thus does it get the material out of which memory, imagination, and thought begin. Thus and only thus does the mind secure the crude material from which the finished superstructure is finally built.



CHAPTER IV

MENTAL DEVELOPMENT AND MOTOR TRAINING

Education was long looked upon as affecting the mind only; the body was either left out of account or neglected. Later science has shown, however, that the mind cannot be trained except as the nervous system is trained and developed. For not sensation and the simpler mental processes alone, but memory, imagination, judgment, reasoning and every other act of the mind are dependent on the nervous system finally for their efficiency. The little child gets its first mental experiences in connection with certain movements or acts set up reflexly by the pre-organized nervous system. From this time on movement and idea are so inextricably bound together that they cannot be separated. The mind and the brain are so vitally related that it is impossible to educate one without performing a like office for the other; and it is likewise impossible to neglect the one without causing the other to suffer in its development.

1. FACTORS DETERMINING THE EFFICIENCY OF THE NERVOUS SYSTEM

DEVELOPMENT AND NUTRITION.—Ignoring the native differences in nervous systems through the influence of heredity, the efficiency of a nervous system is largely dependent on two factors: (1) The development of the cells and fibers of which it is composed, and (2) its general tone of health and vigor. The actual number of cells in the nervous system increases but little if at all after birth. Indeed, it is doubtful whether Edison's brain and nervous system has a greater number of cells in it than yours or mine. The difference between the brain of a genius and that of an ordinary man is not in the number of cells which it contains, but rather in the development of the cells and fibers which are present, potentially, at least, in every nervous system. The histologist tells us that in the nervous system of every child there are tens of thousands of cells which are so immature and undeveloped that they are useless; indeed, this is the case to some degree in every adult person's nervous system as well. Thus each individual has inherent in his nervous system potentialities of which he has never taken advantage, the utilizing of which may make him a genius and the neglecting of which will certainly leave him on the plane of mediocrity. The first problem in education, then, is to take the unripe and inefficient nervous system and so develop it in connection with the growing mind that the possibilities which nature has stored in it shall become actualities.

UNDEVELOPED CELLS.—Professor Donaldson tells us on this point that: "At birth, and for a long time after, many [nervous] systems contain cell elements which are more or less immature, not forming a functional part of the tissue, and yet under some conditions capable of further development.... For the cells which are continually appearing in the developing cortex no other source is known than the nuclei or granules found there in its earliest stages. These elements are metamorphosed neuroblasts—that is, elementary cells out of which the nervous matter is developed—which have shrunken to a volume less than that which they had at first, and which remain small until, in the subsequent process of enlargement necessary for their full development, they expand into well-marked cells. Elements intermediate between these granules and the fully developed cells are always found, even in mature brains, and therefore it is inferred that the latter are derived from the former. The appearances there also lead to the conclusion that many elements which might possibly develop in any given case are far beyond the number that actually does so.... The possible number of cells latent and functional in the central system is early fixed. At any age this number is accordingly represented by the granules as well as by the cells which have already undergone further development. During growth the proportion of developed cells increases, and sometimes, owing to the failure to recognize potential nerve cells in the granules, the impression is carried away that this increase implies the formation of new elements. As has been shown, such is not the case."[1]

DEVELOPMENT OF NERVE FIBERS.—The nerve fibers, no less than the cells, must go through a process of development. It has already been shown that the fibers are the result of a branching of cells. At birth many of the cells have not yet thrown out branches, and hence the fibers are lacking; while many of those which are already grown out are not sufficiently developed to transmit impulses accurately. Thus it has been found that most children at birth are able to support the weight of the body for several seconds by clasping the fingers around a small rod, but it takes about a year for the child to become able to stand. It is evident that it requires more actual strength to cling to a rod than to stand; hence the conclusion is that the difference is in the earlier development of the nerve centers which have to do with clasping than of those concerned in standing. Likewise the child's first attempts to feed himself or do any one of the thousand little things about which he is so awkward, are partial failures not so much because he has not had practice as because his nervous machinery connected with those movements is not yet developed sufficiently to enable him to be accurate. His brain is in a condition which Flechsig calls "unripe." How, then, shall the undeveloped cells and system ripen? How shall the undeveloped cells and fibers grow to full maturity and efficiency?

2. DEVELOPMENT OF NERVOUS SYSTEM THROUGH USE

IMPORTANCE OF STIMULUS AND RESPONSE.—Like all other tissues of the body, the nerve cells and fibers are developed by judicious use. The sensory and association centers require the constant stimulus of nerve currents running in from the various end-organs, and the motor centers require the constant stimulus of currents running from them out to the muscles. In other words, the conditions upon which both motor and sensory development depend are: (1) A rich environment of sights and sounds and tastes and smells, and everything else which serves as proper stimulus to the sense organs, and to every form of intellectual and social interest; and (2) no less important, an opportunity for the freest and most complete forms of response and motor activity.



An illustration of the effects of the lack of sensory stimuli on the cortex is well shown in the case of Laura Bridgman, whose brain was studied by Professor Donaldson after her death. Laura Bridgman was born a normal child, and developed as other children do up to the age of nearly three years. At this time, through an attack of scarlet fever, she lost her hearing completely and also the sight of her left eye. Her right eye was so badly affected that she could see but little; and it, too, became entirely blind when she was eight. She lived in this condition until she was sixty years old, when she died. Professor Donaldson submitted the cortex of her brain to a most careful examination, also comparing the corresponding areas on the two hemispheres with each other. He found that as a whole the cortex was thinner than in the case of normal individuals. He found also that the cortical area connected with the left eye—namely, the right occipital region—was much thinner than that for the right eye, which had retained its sight longer than the other. He says: "It is interesting to notice that those parts of the cortex which, according to the current view, were associated with the defective sense organs were also particularly thin. The cause of this thinness was found to be due, at least in part, to the small size of the nerve cells there present. Not only were the large and medium-sized cells smaller, but the impression made on the observer was that they were also less numerous than in the normal cortex."

EFFECT OF SENSORY STIMULI.—No doubt if we could examine the brain of a person who has grown up in an environment rich in stimuli to the eye, where nature, earth, and sky have presented a changing panorama of color and form to attract the eye; where all the sounds of nature, from the chirp of the insect to the roar of the waves and the murmur of the breeze, and from the softest tones of the voice to the mightiest sweep of the great orchestra, have challenged the ear; where many and varied odors and perfumes have assailed the nostrils; where a great range of tastes have tempted the palate; where many varieties of touch and temperature sensations have been experienced—no doubt if we could examine such a brain we should find the sensory areas of the cortex excelling in thickness because its cells were well developed and full sized from the currents which had been pouring into them from the outside world. On the other hand, if we could examine a cortex which had lacked any one of these stimuli, we should find some area in it undeveloped because of this deficiency. Its owner therefore possesses but the fraction of a brain, and would in a corresponding degree find his mind incomplete.

NECESSITY FOR MOTOR ACTIVITY.—Likewise in the case of the motor areas. Pity the boy or girl who has been deprived of the opportunity to use every muscle to the fullest extent in the unrestricted plays and games of childhood. For where such activities are not wide in their scope, there some areas of the cortex will remain undeveloped, because unused, and the person will be handicapped later in his life from lack of skill in the activities depending on these centers. Halleck says in this connection: "If we could examine the developing motor region with a microscope of sufficient magnifying power, it is conceivable that we might learn wherein the modification due to exercise consists. We might also, under such conditions, be able to say, 'This is the motor region of a piano player; the modifications here correspond precisely to those necessary for controlling such movements of the hand.' Or, 'This is the motor tract of a blacksmith; this, of an engraver; and these must be the cells which govern the vocal organs of an orator.'" Whether or not the microscope will ever reveal such things to us, there is no doubt that the conditions suggested exist, and that back of every inefficient and awkward attempt at physical control lies a motor area with its cells undeveloped by use. No wonder that our processes of learning physical adjustment and control are slow, for they are a growth in the brain rather than a simple "learning how."

The training of the nervous system consists finally, then, in the development and cooerdination of the neurones of which it is composed. We have seen that the sensory cells are to be developed by the sensory stimuli pouring in upon them, and the motor cells by the motor impulses which they send out to the muscles. The sensory and the motor fibers likewise, being an outgrowth of their respective cells, find their development in carrying the impulses which result in sensation and movement. Thus it is seen that the neurone is, in its development as in its work, a unit.

DEVELOPMENT OF THE ASSOCIATION CENTERS.—To this simpler type of sensory and motor development which we have been considering, we must add that which comes from the more complex mental processes, such as memory, thought, and imagination. For it is in connection with these that the association fibers are developed, and the brain areas so connected that they can work together as a unit. A simple illustration will enable us to see more clearly how the nervous mechanism acts to bring this about.

Suppose that I am walking along a country road deeply engaged in meditation, and that I come to a puddle of water in my pathway. I may turn aside and avoid the obstruction without my attention being called to it, and without interruption of my train of thought. The act has been automatic. In this case the nerve current has passed from the eye (S) over an afferent fiber to a sensory center (s) in the nervous system below the cortex; from there it has been forwarded to a motor center (m) in the same region, and on out over a motor fiber to the proper muscles (M), which are to execute the required act. The act having been completed, the sensory nerves connected with the muscles employed report the fact back that the work is done, thus completing the circuit. This event may be taken as an illustration of literally thousands of acts which we perform daily without the intervention of consciousness, and hence without involving the hemispheres.



If, however, instead of avoiding the puddle unconsciously, I do so from consideration of the danger of wet feet and the disagreeableness of soiled shoes and the ridiculous appearance I shall make, then the current cannot take the short circuit, but must pass on up to the cortex. Here it awakens consciousness to take notice of the obstruction, and calls forth the images which aid in directing the necessary movements. This simple illustration may be greatly complicated, substituting for it one of the more complex problems which are continually presenting themselves to us for solution, or the associated trains of thought that are constantly occupying our minds. But the truth of the illustration still holds. Whether in the simple or the complex act, there is always a forward passing of the nerve current through the sensory and thought centers, and on out through the motor centers to the organs which are to be concerned in the motor response.

THE FACTORS INVOLVED IN A SIMPLE ACTION.—Thus it will be seen that in the simplest act which can be considered there are the following factors: (1) The stimulus which acts on the end-organ; (2) the ingoing current over an afferent nerve; (3) the sensory or interpreting cells; (4) the fibers connecting the sensory with a motor center; (5) the motor cells; (6) the efferent nerve to carry the direction for the movement outward to the muscle; (7) the motor response; and, finally, (8) the report back that the act has been performed. With this in mind it fairly bewilders one to think of the marvelous complexity of the work that is going on in our nervous mechanism every moment of our life, even without considering the higher thought processes at all. How, with these added, the resulting complexity all works out into beautiful harmony is indeed beyond comprehension.

3. EDUCATION AND THE TRAINING OF THE NERVOUS SYSTEM

Fortunately, many of the best opportunities for sensory and motor training do not depend on schools or courses of study. The world is full of stimuli to our senses and to our social natures; and our common lives are made up of the responses we make to these stimuli,—the movements, acts and deeds by which we fit ourselves into our world of environment. Undoubtedly the most rapid and vital progress we make in our development is accomplished in the years before we have reached the age to go to school. Yet it is the business of education to see that we do not lack any essential opportunity, to make sure that necessary lines of stimuli or of motor training have not been omitted from our development.

EDUCATION TO SUPPLY OPPORTUNITIES FOR STIMULUS AND RESPONSE.—The great problem of education is, on the physical side, it would seem, then, to provide for ourselves and those we seek to educate as rich an environment of sensory and social stimuli as possible; one whose impressions will be full of suggestions to response in motor activity and the higher thought processes; and then to give opportunity for thought and for expression in acts and deeds in the largest possible number of lines. And added to this must be frequent and clear sensory and motor recall, a living over again of the sights and sounds and odors and the motor activities we have once experienced. There must also be the opportunity for the forming of worthy plans and ideals. For in this way the brain centers which were concerned in the original sensation or thought or movement are again brought into exercise, and their development continued. Through recall and imagination we are able not only greatly to multiply the effects of the immediate sensory and motor stimuli which come to us, but also to improve our power of thinking by getting a fund of material upon which the mind can draw.

ORDER OF DEVELOPMENT IN THE NERVOUS SYSTEM.—Nature has set the order in which the powers of the nervous system shall develop. And we must follow this order if we would obtain the best results. Stated in technical terms, the order is from fundamental to accessory. This is to say that the nerve centers controlling the larger and more general movements of the body ripen first, and those governing the finer motor adjustments later. For example, the larger body muscles of the child which are concerned with sitting up come under control earlier than those connected with walking. The arm muscles develop control earlier than the finger muscles, and the head and neck muscles earlier than the eye muscles. So also the more general and less highly specialized powers of the mind ripen sooner than the more highly specialized. Perception and observation precede powers of critical judgment and association. Memory and imagination ripen earlier than reasoning and the logical ability.

This all means that our educational system must be planned to follow the order of nature. Children of the primary grades should not be required to write with fine pencils or pens which demand delicate finger adjustments, since the brain centers for these finer cooerdinations are not yet developed. Young children should not be set at work necessitating difficult eye control, such as stitching through perforated cardboard, reading fine print and the like, as their eyes are not yet ready for such tasks. The more difficult analytical problems of arithmetic and relations of grammar should not be required of pupils at a time when the association areas of the brain are not yet ready for this type of thinking. For such methods violate the law of nature, and the child is sure to suffer the penalty.

4. IMPORTANCE OF HEALTH AND VIGOR OF THE NERVOUS SYSTEM

Parallel with opportunities for proper stimuli and response the nervous system must possess good tonicity, or vigor. This depends in large degree on general health and nutrition, with freedom from overfatigue. No favorableness of environment nor excellence of training can result in an efficient brain if the nerve energy has run low from depleted health, want of proper nourishment, or exhaustion.

THE INFLUENCE OF FATIGUE.—Histologists find that the nuclei of nerve cells are shrunk as much as fifty per cent by extreme fatigue. Reasonable fatigue followed by proper recuperation is not harmful, but even necessary if the best development is to be attained; but fatigue without proper nourishment and rest is fatal to all mental operations, and indeed finally to the nervous system itself, leaving it permanently in a condition of low tone, and incapable of rallying to strong effort. For rapid and complete recuperation the cells must have not only the best of nourishment but opportunity for rest as well.

Extreme and long-continued fatigue is hostile to the development and welfare of any nervous system, and especially to that of children. Not only does overfatigue hinder growth, but it also results in the formation of certain toxins, or poisons, in the organism, which are particularly harmful to nervous tissue. It is these fatigue toxins that account for many of the nervous and mental disorders which accompany breakdowns from overwork. On the whole, the evil effects from mental overstrain are more to be feared than from physical overstrain.

THE EFFECTS OF WORRY.—There is, perhaps, no greater foe to brain growth and efficiency than the nervous and worn-out condition which comes from loss of sleep or from worry. Experiments in the psychological laboratories have shown that nerve cells shrivel up and lose their vitality under loss of sleep. Let this go on for any considerable length of time, and the loss is irreparable; for the cells can never recuperate. This is especially true in the case of children or young people. Many school boys and girls, indeed many college students, are making slow progress in their studies not because they are mentally slow or inefficient, not even chiefly because they lose time that should be put on their lessons, but because they are incapacitating their brains for good service through late hours and the consequent loss of sleep. Add to this condition that of worry, which often accompanies it from the fact of failure in lessons, and a naturally good and well-organized nervous system is sure to fail. Worry, from whatever cause, should be avoided as one would avoid poison, if we would bring ourselves to the highest degree of efficiency. Not only does worry temporarily unfit the mind for its best work, but its evil results are permanent, since the mind is left with a poorly developed or undone nervous system through which to work, even after the cause for worry has been removed and the worry itself has ceased.

Not only should each individual seek to control the causes of worry in his own life, but the home and the school should force upon childhood as few causes for worry as may be. Children's worry over fears of the dark, over sickness and death, over prospective but delayed punishment, over the thousand and one real or imaginary troubles of childhood, should be eliminated so far as possible. School examinations that prey on the peace of mind, threats of failure of promotion, all nagging and sarcasm, and whatever else may cause continued pain or worry to sensitive minds should be barred from our schoolroom methods and practice. The price we force the child to pay for results through their use is too great for them to be tolerated. We must seek a better way.

THE FACTORS IN GOOD NUTRITION.—For the best nutrition there is necessity first of all plenty of nourishing and healthful food. Science and experience have both disproved the supposition that students should be scantily fed. O'Shea claims that many brain workers are far short of their highest grade of efficiency because of starving their brains from poor diet. And not only must the food be of the right quality, but the body must be in good health. Little good to eat the best of food unless it is being properly digested and assimilated. And little good if all the rest is as it should be, and the right amount of oxidation does not go on in the brain so as to remove the worn-out cells and make place for new ones. This warns us that pure air and a strong circulation are indispensable to the best working of our brains. No doubt many students who find their work too hard for them might locate the trouble in their stomachs or their lungs or the food they eat, rather than in their minds.

5. PROBLEMS FOR INTROSPECTION AND OBSERVATION

1. Estimate the mental progress made by the child during the first five years and compare with that made during the second five years of its life. To do this make a list, so far as you are able, of the acquisitions of each period. What do you conclude as to the importance of play and freedom in early education? Why not continue this method instead of sending the child to school?

2. Which has the better opportunity for sensory training, the city child or the country child? For social training? For motor development through play? It is said by specialists that country children are not as good players as city children. Why should this be the case?

3. Observe carefully some group of children for evidences of lack of sensory training (Interest in sensory objects, skill in observation, etc.). For lack of motor training (Failure in motor control, awkwardness, lack of skill in play, etc.). Do you find that general mental ability seems to be correlated with sensory and motor ability, or not?

4. What sensory training can be had from (1) geography, (2) agriculture, (3) arithmetic, (4) drawing? What lines of motor training ought the school to afford, (1) in general, (2) for the hand, (3) in the grace and poise of carriage or bearing, (4) in any other line? Make observation tests of these points in one or more school rooms and report the results.

5. Describe what you think must be the type of mental life of Helen Keller. (Read "The World I Live In," by Helen Keller.)

6. Study groups of children for signs of deficiency in brain power from lack of nutrition. From fatigue. From worry. From lack of sleep.



CHAPTER V

HABIT

Habit is our "best friend or worst enemy." We are "walking bundles of habits." Habit is the "fly-wheel of society," keeping men patient and docile in the hard or disagreeable lot which some must fill. Habit is a "cable which we cannot break." So say the wise men. Let me know your habits of life and you have revealed your moral standards and conduct. Let me discover your intellectual habits, and I understand your type of mind and methods of thought. In short, our lives are largely a daily round of activities dictated by our habits in this line or that. Most of our movements and acts are habitual; we think as we have formed the habit of thinking; we decide as we are in the habit of deciding; we sleep, or eat, or speak as we have grown into the habit of doing these things; we may even say our prayers or perform other religious exercises as matters of habit. But while habit is the veriest tyrant, yet its good offices far exceed the bad even in the most fruitless or depraved life.

1. THE NATURE OF HABIT

Many people when they speak or think of habit give the term a very narrow or limited meaning. They have in mind only certain moral or personal tendencies usually spoken of as one's "habits." But in order to understand habit in any thorough and complete way we must, as suggested by the preceding paragraph, broaden our concept to include every possible line of physical and mental activity. Habit may be defined as the tendency of the nervous system to repeat any act that has been performed once or many times.

THE PHYSICAL BASIS OF HABIT.—Habit is to be explained from the standpoint of its physical basis. Habits are formed because the tissues of our brains are capable of being modified by use, and of so retaining the effects of this modification that the same act is easier of performance each succeeding time. This results in the old act being repeated instead of a new one being selected, and hence the old act is perpetuated.

Even dead and inert matter obeys the same principles in this regard as does living matter. Says M. Leon Dumont: "Everyone knows how a garment, having been worn a certain time, clings to the shape of the body better than when it was new; there has been a change in the tissue, and this change is a new habit of cohesion; a lock works better after having been used some time; at the outset more force was required to overcome certain roughness in the mechanism. The overcoming of this resistance is a phenomenon of habituation. It costs less trouble to fold a paper when it has been folded already. This saving of trouble is due to the essential nature of habit, which brings it about that, to reproduce the effect, a less amount of the outward cause is required. The sounds of a violin improve by use in the hands of an able artist, because the fibers of the wood at last contract habits of vibration conformed to harmonic relations. This is what gives such inestimable value to instruments that have belonged to great masters. Water, in flowing, hollows out for itself a channel, which grows broader and deeper; and, after having ceased to flow, it resumes when it flows again the path traced for itself before. Just so, the impressions of outer objects fashion for themselves in the nervous system more and more appropriate paths, and these vital phenomena recur under similar excitements from without, when they have been interrupted for a certain time."[2]

ALL LIVING TISSUE PLASTIC.—What is true of inanimate matter is doubly true of living tissue. The tissues of the human body can be molded into almost any form you choose if taken in time. A child may be placed on his feet at too early an age, and the bones of his legs form the habit of remaining bent. The Flathead Indian binds a board on the skull of his child, and its head forms the habit of remaining flat on the top. Wrong bodily postures produce curvature of the spine, and pernicious modes of dress deform the bones of the chest. The muscles may be trained into the habit of keeping the shoulders straight or letting them droop; those of the back, to keep the body well up on the hips, or to let it sag; those of locomotion, to give us a light, springy step, or to allow a shuffling carriage; those of speech, to give us a clear-cut, accurate articulation, or a careless, halting one; and those of the face, to give us a cheerful cast of countenance, or a glum and morose expression.

HABIT A MODIFICATION OF BRAIN TISSUE.—But the nervous tissue is the most sensitive and easily molded of all bodily tissues. In fact, it is probable that the real habit of our characteristic walk, gesture, or speech resides in the brain, rather than in the muscles which it controls. So delicate is the organization of the brain structure and so unstable its molecules, that even the perfume of the flower, which assails the nose of a child, the song of a bird, which strikes his ear, or the fleeting dream, which lingers but for a second in his sleep, has so modified his brain that it will never again be as if these things had not been experienced. Every sensory current which runs in from the outside world; every motor current which runs out to command a muscle; every thought that we think, has so modified the nerve structure through which it acts, that a tendency remains for a like act to be repeated. Our brain and nervous system is daily being molded into fixed habits of acting by our thoughts and deeds, and thus becomes the automatic register of all we do.

The old Chinese fairy story hits upon a fundamental and vital truth. These celestials tell their children that each child is accompanied by day and by night, every moment of his life, by an invisible fairy, who is provided with a pencil and tablet. It is the duty of this fairy to put down every deed of the child, both good and evil, in an indelible record which will one day rise as a witness against him. So it is in very truth with our brains. The wrong act may have been performed in secret, no living being may ever know that we performed it, and a merciful Providence may forgive it; but the inexorable monitor of our deeds was all the time beside us writing the record, and the history of that act is inscribed forever in the tissues of our brain. It may be repented of bitterly in sackcloth and ashes and be discontinued, but its effects can never be quite effaced; they will remain with us a handicap till our dying day, and in some critical moment in a great emergency we shall be in danger of defeat from that long past and forgotten act.

WE MUST FORM HABITS.—We must, then, form habits. It is not at all in our power to say whether we will form habits or not; for, once started, they go on forming themselves by day and night, steadily and relentlessly. Habit is, therefore, one of the great factors to be reckoned with in our lives, and the question becomes not, Shall we form habits? but What habits we shall form. And we have the determining of this question largely in our own power, for habits do not just happen, nor do they come to us ready made. We ourselves make them from day to day through the acts we perform, and in so far as we have control over our acts, in that far we can determine our habits.

2. THE PLACE OF HABIT IN THE ECONOMY OF OUR LIVES

Habit is one of nature's methods of economizing time and effort, while at the same time securing greater skill and efficiency. This is easily seen when it is remembered that habit tends towards automatic action; that is, towards action governed by the lower nerve centers and taking care of itself, so to speak, without the interference of consciousness. Everyone has observed how much easier in the performance and more skillful in its execution is the act, be it playing a piano, painting a picture, or driving a nail, when the movements involved have ceased to be consciously directed and become automatic.

HABIT INCREASES SKILL AND EFFICIENCY.—Practically all increase in skill, whether physical or mental, depends on our ability to form habits. Habit holds fast to the skill already attained while practice or intelligence makes ready for the next step in advance. Could we not form habits we should improve but little in our way of doing things, no matter how many times we did them over. We should now be obliged to go through the same bungling process of dressing ourselves as when we first learned it as children. Our writing would proceed as awkwardly in the high school as the primary, our eating as adults would be as messy and wide of the mark as when we were infants, and we should miss in a thousand ways the motor skill that now seems so easy and natural. All highly skilled occupations, and those demanding great manual dexterity, likewise depend on our habit-forming power for the accurate and automatic movements required.

So with mental skill. A great portion of the fundamentals of our education must be made automatic—must become matters of habit. We set out to learn the symbols of speech. We hear words and see them on the printed page; associated with these words are meanings, or ideas. Habit binds the word and the idea together, so that to think of the one is to call up the other—and language is learned. We must learn numbers, so we practice the "combinations," and with 4x6, or 3x8 we associate 24. Habit secures this association in our minds, and lo! we soon know our "tables." And so on throughout the whole range of our learning. We learn certain symbols, or facts, or processes, and habit takes hold and renders these automatic so that we can use them freely, easily, and with skill, leaving our thought free for matters that cannot be made automatic. One of our greatest dangers is that we shall not make sufficiently automatic, enough of the necessary foundation material of education. Failing in this, we shall at best be but blunderers intellectually, handicapped because we failed to make proper use of habit in our development.

For, as we have seen in an earlier chapter, there is a limit to our mental energy and also to the number of objects to which we are able to attend. It is only when attention has been freed from the many things that can always be thought or done in the same way, that the mind can devote itself to the real problems that require judgment, imagination or reasoning. The writer whose spelling and punctuation do not take care of themselves will hardly make a success of writing. The mathematician whose number combinations, processes and formulae are not automatic in his mind can never hope to make progress in mathematical thinking. The speaker who, while speaking, has to think of his gestures, his voice or his enunciation will never sway audiences by his logic or his eloquence.

HABIT SAVES EFFORT AND FATIGUE.—We do most easily and with least fatigue that which we are accustomed to do. It is the new act or the strange task that tires us. The horse that is used to the farm wearies if put on the road, while the roadster tires easily when hitched to the plow. The experienced penman works all day at his desk without undue fatigue, while the man more accustomed to the pick and the shovel than to the pen, is exhausted by a half hour's writing at a letter. Those who follow a sedentary and inactive occupation do not tire by much sitting, while children or others used to freedom and action may find it a wearisome task merely to remain still for an hour or two.

Not only would the skill and speed demanded by modern industry be impossible without the aid of habit, but without its help none could stand the fatigue and strain. The new workman placed at a high-speed machine is ready to fall from weariness at the end of his first day. But little by little he learns to omit the unnecessary movements, the necessary movements become easier and more automatic through habit, and he finds the work easier. We may conclude, then, that not only do consciously directed movements show less skill than the same movements made automatic by habit, but they also require more effort and produce greater fatigue.

HABIT ECONOMIZES MORAL EFFORT.—To have to decide each time the question comes up whether we will attend to this lecture or sermon or lesson; whether we will persevere and go through this piece of disagreeable work which we have begun; whether we will go to the trouble of being courteous and kind to this or that poor or unlovely or dirty fellow-mortal; whether we will take this road because it looks easy, or that one because we know it to be the one we ought to take; whether we will be strictly fair and honest when we might just as well be the opposite; whether we will resist the temptation which dares us; whether we will do this duty, hard though it is, which confronts us—to have to decide each of these questions every time it presents itself is to put too large a proportion of our thought and energy on things which should take care of themselves. For all these things should early become so nearly habitual that they can be settled with the very minimum of expenditure of energy when they arise.

THE HABIT OF ATTENTION.—It is a noble thing to be able to attend by sheer force of will when the interest lags, or some more attractive thing appears, but far better is it so to have formed the habit of attention that we naturally fall into that attitude when this is the desirable thing. To understand what I mean, you only have to look over a class or an audience and note the different ways which people have of finally settling down to listening. Some with an attitude which says, "Now here I am, ready to listen to you if you will interest me, otherwise not." Others with a manner which says, "I did not really come here expecting to listen, and you will have a large task if you interest me; I never listen unless I am compelled to, and the responsibility rests on you." Others plainly say, "I really mean to listen, but I have hard work to control my thoughts, and if I wander I shall not blame you altogether; it is just my way." And still others say, "When I am expected to listen, I always listen whether there is anything much to listen to or not. I have formed that habit, and so have no quarrel with myself about it. You can depend on me to be attentive, for I cannot afford to weaken my habit of attention whether you do well or not." Every speaker will clasp these last listeners to his heart and feed them on the choicest thoughts of his soul; they are the ones to whom he speaks and to whom his address will appeal.

HABIT ENABLES US TO MEET THE DISAGREEABLE.—To be able to persevere in the face of difficulties and hardships and carry through the disagreeable thing in spite of the protests of our natures against the sacrifice which it requires, is a creditable thing; but it is more creditable to have so formed the habit of perseverance that the disagreeable duty shall be done without a struggle, or protest, or question. Horace Mann testifies of himself that whatever success he was able to attain was made possible through the early habit which he formed of never stopping to inquire whether he liked to do a thing which needed doing, but of doing everything equally well and without question, both the pleasant and the unpleasant.

The youth who can fight out a moral battle and win against the allurements of some attractive temptation is worthy the highest honor and praise; but so long as he has to fight the same battle over and over again, he is on dangerous ground morally. For good morals must finally become habits, so ingrained in us that the right decision comes largely without effort and without struggle. Otherwise the strain is too great, and defeat will occasionally come; and defeat means weakness and at last disaster, after the spirit has tired of the constant conflict. And so on in a hundred lines. Good habits are more to be coveted than individual victories in special cases, much as these are to be desired. For good habits mean victories all along the line.

HABIT THE FOUNDATION OF PERSONALITY.—The biologist tells us that it is the constant and not the occasional in the environment that impresses itself on an organism. So also it is the habitual in our lives that builds itself into our character and personality. In a very real sense we are what we are in the habit of doing and thinking.

Without habit, personality could not exist; for we could never do a thing twice alike, and hence would be a new person each succeeding moment. The acts which give us our own peculiar individuality are our habitual acts—the little things that do themselves moment by moment without care or attention, and are the truest and best expression of our real selves. Probably no one of us could be very sure which arm he puts into the sleeve, or which foot he puts into the shoe, first; and yet each of us certainly formed the habit long ago of doing these things in a certain way. We might not be able to describe just how we hold knife and fork and spoon, and yet each has his own characteristic and habitual way of handling them. We sit down and get up in some characteristic way, and the very poise of our heads and attitudes of our bodies are the result of habit. We get sleepy and wake up, become hungry and thirsty at certain hours, through force of habit. We form the habit of liking a certain chair, or nook, or corner, or path, or desk, and then seek this to the exclusion of all others. We habitually use a particular pitch of voice and type of enunciation in speaking, and this becomes one of our characteristic marks; or we form the habit of using barbarisms or solecisms of language in youth, and these cling to us and become an inseparable part of us later in life.

On the mental side the case is no different. Our thinking is as characteristic as our physical acts. We may form the habit of thinking things out logically, or of jumping to conclusions; of thinking critically and independently, or of taking things unquestioningly on the authority of others. We may form the habit of carefully reading good, sensible books, or of skimming sentimental and trashy ones; of choosing elevating, ennobling companions, or the opposite; of being a good conversationalist and doing our part in a social group, or of being a drag on the conversation, and needing to be "entertained." We may form the habit of observing the things about us and enjoying the beautiful in our environment, or of failing to observe or to enjoy. We may form the habit of obeying the voice of conscience or of weakly yielding to temptation without a struggle; of taking a reverent attitude of prayer in our devotions, or of merely saying our prayers.

HABIT SAVES WORRY AND REBELLION.—Habit has been called the "balance wheel" of society. This is because men readily become habituated to the hard, the disagreeable, or the inevitable, and cease to battle against it. A lot that at first seems unendurable after a time causes less revolt. A sorrow that seems too poignant to be borne in the course of time loses some of its sharpness. Oppression or injustice that arouses the fiercest resentment and hate may finally come to be accepted with resignation. Habit helps us learn that "what cannot be cured must be endured."

3. THE TYRANNY OF HABIT

EVEN GOOD HABITS NEED TO BE MODIFIED.—But even in good habits there is danger. Habit is the opposite of attention. Habit relieves attention of unnecessary strain. Every habitual act was at one time, either in the history of the race or of the individual, a voluntary act; that is, it was performed under active attention. As the habit grew, attention was gradually rendered unnecessary, until finally it dropped entirely out. And herein lies the danger. Habit once formed has no way of being modified unless in some way attention is called to it, for a habit left to itself becomes more and more firmly fixed. The rut grows deeper. In very few, if any, of our actions can we afford to have this the case. Our habits need to be progressive, they need to grow, to be modified, to be improved. Otherwise they will become an incrusting shell, fixed and unyielding, which will limit our growth.

It is necessary, then, to keep our habitual acts under some surveillance of attention, to pass them in review for inspection every now and then, that we may discover possible modifications which will make them more serviceable. We need to be inventive, constantly to find out better ways of doing things. Habit takes care of our standing, walking, sitting; but how many of us could not improve his poise and carriage if he would? Our speech has become largely automatic, but no doubt all of us might remove faults of enunciation, pronunciation or stress from our speaking. So also we might better our habits of study and thinking, our methods of memorizing, or our manner of attending.

THE TENDENCY OF "RUTS."—But this will require something of heroism. For to follow the well-beaten path of custom is easy and pleasant, while to break out of the rut of habit and start a new line of action is difficult and disturbing. Most people prefer to keep doing things as they always have done them, to continue reading and thinking and believing as they have long been in the habit of doing, not so much because they feel that their way is best, but because it is easier than to change. Hence the great mass of us settle down on the plane of mediocrity, and become "old fogy." We learn to do things passably well, cease to think about improving our ways of doing them, and so fall into a rut. Only the few go on. They make use of habit as the rest do, but they also continue to attend at critical points of action, and so make habit an ally in place of accepting it as a tyrant.

4. HABIT-FORMING A PART OF EDUCATION

It follows from the importance of habit in our lives that no small part of education should be concerned with the development of serviceable habits. Says James, "Could the young but realize how soon they will become mere walking bundles of habits, they would give more heed to their conduct while in the plastic state. We are spinning our own fates, good or evil, and never to be undone. Every smallest stroke of virtue or of vice leaves its never-so-little scar." Any youth who is forming a large number of useful habits is receiving no mean education, no matter if his knowledge of books may be limited; on the other hand, no one who is forming a large number of bad habits is being well educated, no matter how brilliant his knowledge may be.

YOUTH THE TIME FOR HABIT-FORMING.—Childhood and youth is the great time for habit-forming. Then the brain is plastic and easily molded, and it retains its impressions more indelibly; later it is hard to modify, and the impressions made are less permanent. It is hard to teach an old dog new tricks; nor would he remember them if you could teach them to him, nor be able to perform them well even if he could remember them. The young child will, within the first few weeks of its life, form habits of sleeping and feeding. It may in a few days be led into the habit of sleeping in the dark, or requiring a light; of going to sleep lying quietly, or of insisting upon being rocked; of getting hungry by the clock, or of wanting its food at all times when it finds nothing else to do, and so on. It is wholly outside the power of the mother or the nurse to determine whether the child shall form habits, but largely within their power to say what habits shall be formed, since they control his acts.

As the child grows older, the range of his habits increases; and by the time he has reached his middle teens, the greater number of his personal habits are formed. It is very doubtful whether a boy who has not formed habits of punctuality before the age of fifteen will ever be entirely trustworthy in matters requiring precision in this line. The girl who has not, before this age, formed habits of neatness and order will hardly make a tidy housekeeper later in her life. Those who in youth have no opportunity to habituate themselves to the usages of society may study books on etiquette and employ private instructors in the art of polite behavior all they please later in life, but they will never cease to be awkward and ill at ease. None are at a greater disadvantage than the suddenly-grown-rich who attempt late in life to surround themselves with articles of art and luxury, though their habits were all formed amid barrenness and want during their earlier years.

THE HABIT OF ACHIEVEMENT.—What youth does not dream of being great, or noble, or a celebrated scholar! And how few there are who finally achieve their ideals! Where does the cause of failure lie? Surely not in the lack of high ideals. Multitudes of young people have "Excelsior!" as their motto, and yet never get started up the mountain slope, let alone toiling on to its top. They have put in hours dreaming of the glory farther up, and have never begun to climb. The difficulty comes in not realizing that the only way to become what we wish or dream that we may become is to form the habit of being that thing. To form the habit of achievement, of effort, of self-sacrifice, if need be. To form the habit of deeds along with dreams; to form the habit of doing.

Who of us has not at this moment lying in wait for his convenience in the dim future a number of things which he means to do just as soon as this term of school is finished, or this job of work is completed, or when he is not so busy as now? And how seldom does he ever get at these things at all! Darwin tells that in his youth he loved poetry, art, and music, but was so busy with his scientific work that he could ill spare the time to indulge these tastes. So he promised himself that he would devote his time to scientific work and make his mark in this. Then he would have time for the things that he loved, and would cultivate his taste for the fine arts. He made his mark in the field of science, and then turned again to poetry, to music, to art. But alas! they were all dead and dry bones to him, without life or interest. He had passed the time when he could ever form the taste for them. He had formed his habits in another direction, and now it was forever too late to form new habits. His own conclusion is, that if he had his life to live over again, he would each week listen to some musical concert and visit some art gallery, and that each day he would read some poetry, and thereby keep alive and active the love for them.

So every school and home should be a species of habit-factory—a place where children develop habits of neatness, punctuality, obedience, politeness, dependability and the other graces of character.

5. RULES FOR HABIT-FORMING

JAMES'S THREE MAXIMS FOR HABIT-FORMING.—On the forming of new habits and the leaving off of old ones, I know of no better statement than that of James, based on Bain's chapter on "Moral Habits." I quote this statement at some length: "In the acquisition of a new habit, or the leaving off of an old one, we must take care to launch ourselves with as strong and decided an initiative as possible. Accumulate all the possible circumstances which shall reenforce right motives; put yourself assiduously in conditions that encourage the new way; make engagements incompatible with the old; take a public pledge, if the case allows; in short, develop your resolution with every aid you know. This will give your new beginning such a momentum that the temptation to break down will not occur as soon as it otherwise might; and every day during which a breakdown is postponed adds to the chances of its not occurring at all.

"The second maxim is: Never suffer an exception to occur until the new habit is securely rooted in your life. Each lapse is like letting fall a ball of string which one is carefully winding up; a single slip undoes more than a great many turns will wind again. Continuity of training is the great means of making the nervous system act infallibly right.... The need of securing success nerves one to future vigor.

"A third maxim may be added to the preceding pair: Seize the very first possible opportunity to act on every resolution you make, and on every emotional prompting you may experience in the direction of the habits you aspire to gain. It is not in the moment of their forming, but in the moment of their producing motor effects, that resolves and aspirations communicate the new 'set' to the brain."[3]

THE PREPONDERANCE OF GOOD HABITS OVER BAD.—And finally, let no one be disturbed or afraid because in a little time you become a "walking bundle of habits." For in so far as your good actions predominate over your bad ones, that much will your good habits outweigh your bad habits. Silently, moment by moment, efficiency is growing out of all worthy acts well done. Every bit of heroic self-sacrifice, every battle fought and won, every good deed performed, is being irradicably credited to you in your nervous system, and will finally add its mite toward achieving the success of your ambitions.

6. PROBLEMS IN OBSERVATION AND INTROSPECTION

1. Select some act which you have recently begun to perform and watch it grow more and more habitual. Notice carefully for a week and see whether you do not discover some habits which you did not know you had. Make a catalog of your bad habits; of the most important of your good ones.

2. Set out to form some new habits which you desire to possess; also to break some undesirable habit, watching carefully what takes place in both cases, and how long it requires.

3. Try the following experiment and relate the results to the matter of automatic control brought about by habit: Draw a star on a sheet of cardboard. Place this on a table before you, with a hand-mirror so arranged that you can see the star in the mirror. Now trace the outline of the star with a pencil, looking steadily in the mirror to guide your hand. Do not lift the pencil from the paper from the time you start until you finish. Have others try this experiment.

4. Study some group of pupils for their habits (1) of attention, (2) of speech, (3) of standing, sitting, and walking, (4) of study. Report on your observations and suggest methods of curing bad habits observed.

5. Make a list of "mannerisms" you have observed, and suggest how they may be cured.

6. Make a list of from ten to twenty habits which you think the school and its work should especially cultivate. What ones of these are the schools you know least successful in cultivating? Where does the trouble lie?



CHAPTER VI

SENSATION

We can best understand the problems of sensation and perception if we first think of the existence of two great worlds—the world of physical nature without and the world of mind within. On the one hand is our material environment, the things we see and hear and touch and taste and handle; and on the other hand our consciousness, the means by which we come to know this outer world and adjust ourselves to it. These two worlds seem in a sense to belong to and require each other. For what would be the meaning or use of the physical world with no mind to know or use it; and what would be the use of a mind with nothing to be known or thought about?

1. HOW WE COME TO KNOW THE EXTERNAL WORLD

There is a marvel about our coming to know the external world which we shall never be able fully to understand. We have come by this knowledge so gradually and unconsciously that it now appears to us as commonplace, and we take for granted many things that it would puzzle us to explain.

KNOWLEDGE THROUGH THE SENSES.—For example, we say, "Of course I see yonder green tree: it is about ten rods distant." But why "of course"? Why should objects at a distance from us and with no evident connection between us and them be known to us at all merely by turning our eyes in their direction when there is light? Why not rather say with the blind son of Professor Puiseaux of Paris, who, when asked if he would like to be restored to sight, answered: "If it were not for curiosity I would rather have long arms. It seems to me that my hands would teach me better what is passing in the moon than your eyes or telescopes."

We listen and then say, "Yes, that is a certain bell ringing in the neighboring village," as if this were the most simple thing in the world. But why should one piece of metal striking against another a mile or two away make us aware that there is a bell there at all, let alone that it is a certain bell whose tone we recognize? Or we pass our fingers over a piece of cloth and decide, "That is silk." But why, merely by placing our skin in contact with a bit of material, should we be able to know its quality, much less that it is cloth and that its threads were originally spun by an insect? Or we take a sip of liquid and say, "This milk is sour." But why should we be able by taking the liquid into the mouth and bringing it into contact with the mucous membrane to tell that it is milk, and that it possesses the quality which we call sour? Or, once more, we get a whiff of air through the open window in the springtime and say, "There is a lilac bush in bloom on the lawn." Yet why, from inhaling air containing particles of lilac, should we be able to know that there is anything outside, much less that it is a flower and of a particular variety which we call lilac? Or, finally, we hold a heated flatiron up near the cheek and say, "This is too hot! it will burn the cloth." But why by holding this object a foot away from the face do we know that it is there, let alone knowing its temperature?

THE UNITY OF SENSORY EXPERIENCE.—Further, our senses come through experience to have the power of fusing, or combining their knowledge, so to speak, by which each expresses its knowledge in terms of the others. Thus we take a glance out of the window and say that the day looks cold, although we well know that we cannot see cold. Or we say that the melon sounds green, or the bell sounds cracked, although a crack or greenness cannot be heard. Or we say that the box feels empty, although emptiness cannot be felt. We have come to associate cold, originally experienced with days which look like the one we now see, with this particular appearance, and so we say we see the cold; sounds like the one coming from the bell we have come to associate with cracked bells, and that coming from the melon with green melons, until we say unhesitatingly that the bell sounds cracked and the melon sounds green. And so with the various senses. Each gleans from the world its own particular bit of knowledge, but all are finally in a partnership and what is each one's knowledge belongs to every other one in so far as the other can use it.

THE SENSORY PROCESSES TO BE EXPLAINED.—The explanation of the ultimate nature of knowledge, and how we reach it through contact with our material environment, we will leave to the philosophers. And battles enough they have over the question, and still others they will have before the matter is settled. The easier and more important problem for us is to describe the processes by which the mind comes to know its environment, and to see how it uses this knowledge in thinking. This much we shall be able to do, for it is often possible to describe a process and discover its laws even when we cannot fully explain its nature and origin. We know the process of digestion and assimilation, and the laws which govern them, although we do not understand the ultimate nature and origin of life which makes these possible.

THE QUALITIES OF OBJECTS EXIST IN THE MIND.—Yet even in the relatively simple description which we have proposed many puzzles confront us, and one of them appears at the very outset. This is that the qualities which we usually ascribe to objects really exist in our own minds and not in the objects at all. Take, for instance, the common qualities of light and color. The physicist tells us that what we see as light is occasioned by an incredibly rapid beating of ether waves on the retina of the eye. All space is filled with this ether; and when it is light—that is, when some object like the sun or other light-giving body is present—the ether is set in motion by the vibrating molecules of the body which is the source of light, its waves strike the retina, a current is produced and carried to the brain, and we see light. This means, then, that space, the medium in which we see objects, is not filled with light (the sensation), but with very rapid waves of ether, and that the light which we see really occurs in our own minds as the mental response to the physical stimulus of ether waves. Likewise with color. Color is produced by ether waves of different lengths and degrees of rapidity.

Thus ether waves at the rate of 450 billions a second give us the sensation of red; of 472 billions a second, orange; of 526 billions a second, yellow; of 589 billions a second, green; of 640 billions a second, blue; of 722 billions a second, indigo; of 790 billions a second, violet. What exists outside of us, then, is these ether waves of different rates, and not the colors (as sensations) themselves. The beautiful yellow and crimson of a sunset, the variegated colors of a landscape, the delicate pink in the cheek of a child, the blush of a rose, the shimmering green of the lake—these reside not in the objects themselves, but in the consciousness of the one who sees them. The objects possess but the quality of reflecting back to the eye ether waves of the particular rate corresponding to the color which we ascribe to them. Thus "red" objects, and no others, reflect back ether waves of a rate of 450 billions a second: "white" objects reflect all rates; "black" objects reflect none.

The case is no different with regard to sound. When we speak of a sound coming from a bell, what we really mean is that the vibrations of the bell have set up waves in the air between it and our ear, which have produced corresponding vibrations in the ear; that a nerve current was thereby produced; and that a sound was heard. But the sound (i.e., sensation) is a mental thing, and exists only in our own consciousness. What passed between the sounding object and ourselves was waves in the intervening air, ready to be translated through the machinery of nerves and brain into the beautiful tones and melodies and harmonies of the mind. And so with all other sensations.

THE THREE SETS OF FACTORS.—What exists outside of us therefore is a stimulus, some form of physical energy, of a kind suitable to excite to activity a certain end-organ of taste, or touch, or smell, or sight, or hearing; what exists within us is the nervous machinery capable of converting this stimulus into a nerve current which shall produce an activity in the cortex of the brain; what results is the mental object which we call a sensation of taste, smell, touch, sight, or hearing.

2. THE NATURE OF SENSATION

SENSATION GIVES US OUR WORLD OF QUALITIES.—In actual experience sensations are never known apart from the objects to which they belong. This is to say that when we see yellow or red it is always in connection with some surface, or object; when we taste sour, this quality belongs to some substance, and so on with all the senses. Yet by sensation we mean only the simple qualities of objects known in consciousness as the result of appropriate stimuli applied to end-organs. We shall later see how by perception these qualities fuse or combine to form objects, but in the present chapter we shall be concerned with the qualities only. Sensations are, then, the simplest and most elementary knowledge we may get from the physical world,—the red, the blue, the bitter, the cold, the fragrant, and whatever other qualities may belong to the external world. We shall not for the present be concerned with the objects or sources from which the qualities may come.

To quote James on the meaning of sensation: "All we can say on this point is that what we mean by sensations are first things in the way of consciousness. They are the immediate results upon consciousness of nerve currents as they enter the brain, and before they have awakened any suggestions or associations with past experience. But it is obvious that such immediate sensations can be realized only in the earliest days of life."

THE ATTRIBUTES OF SENSATION.—Sensations differ from each other in at least four respects; namely, quality, intensity, extensity, and duration.

It is a difference in quality that makes us say, "This paper is red, and that, blue; this liquid is sweet, and that, sour." Differences in quality are therefore fundamental differences in kind. Besides the quality-differences that exist within the same general field, as of taste or vision, it is evident that there is a still more fundamental difference existing between the various fields. One can, for example, compare red with blue or sweet with sour, and tell which quality he prefers. But let him try to compare red with sweet, or blue with sour, and the quality-difference is so profound that there seems to be no basis for comparison.

Differences in intensity of sensation are familiar to every person who prefers two lumps of sugar rather than one lump in his coffee; the sweet is of the same quality in either case, but differs in intensity. In every field of sensation, the intensity may proceed from the smallest amount to the greatest amount discernible. In general, the intensity of the sensation depends on the intensity of the stimulus, though the condition of the sense-organ as regards fatigue or adaptation to the stimulus has its effect. It is obvious that a stimulus may be too weak to produce any sensation; as, for example, a few grains of sugar in a cup of coffee or a few drops of lemon in a quart of water could not be detected. It is also true that the intensity of the stimulus may be so great that an increase in intensity produces no effect on the sensation; as, for example, the addition of sugar to a solution of saccharine would not noticeably increase its sweetness. The lowest and highest intensity points of sensation are called the lower and upper limen, or threshold, respectively.

By extensity is meant the space-differences of sensations. The touch of the point of a toothpick on the skin has a different space quality from the touch of the flat end of a pencil. Low tones seem to have more volume than high tones. Some pains feel sharp and others dull and diffuse. The warmth felt from spreading the palms of the hands out to the fire has a "bigness" not felt from heating one solitary finger. The extensity of a sensation depends on the number of nerve endings stimulated.

The duration of a sensation refers to the time it lasts. This must not be confused with the duration of the stimulus, which may be either longer or shorter than the duration of the sensation. Every sensation must exist for some space of time, long or short, or it would have no part in consciousness.

3. SENSORY QUALITIES AND THEIR END-ORGANS

All are familiar with the "five senses" of our elementary physiologies, sight, hearing, taste, smell, and touch. A more complete study of sensation reveals nearly three times this number, however. This is to say that the body is equipped with more than a dozen different kinds of end-organs, each prepared to receive its own particular type of stimulus. It must also be understood that some of the end-organs yield more than one sense. The eye, for example, gives not only visual but muscular sensations; the ear not only auditory, but tactual; the tongue not only gustatory, but tactual and cold and warmth sensations.

SIGHT.—Vision is a distance sense; we can see afar off. The stimulus is chemical in its action; this means that the ether waves, on striking the retina, cause a chemical change which sets up the nerve current responsible for the sensation.

The eye, whose general structure is sufficiently described in all standard physiologies, consists of a visual apparatus designed to bring the images of objects to a clear focus on the retina at the fovea, or area of clearest vision, near the point of entrance of the optic nerve.

The sensation of sight coming from this retinal image unaided by other sensations gives us but two qualities, light and color. The eye can distinguish many different grades of light from purest white on through the various grays to densest black. The range is greater still in color. We speak of the seven colors of the spectrum, violet, indigo, blue, green, yellow, orange, and red. But this is not a very serviceable classification, since the average eye can distinguish about 35,000 color effects. It is also somewhat bewildering to find that all these colors seem to be produced from the four fundamental hues, red, green, yellow, and blue, plus the various tints. These four, combined in varying proportions and with different degrees of light (i.e., different shades of gray), yield all the color effects known to the human eye. Herschel estimates that the workers on the mosaics at Rome must have distinguished 30,000 different color tones. The hue of a color refers to its fundamental quality, as red or yellow; the chroma, to its saturation, or the strength of the color; and the tint, to the amount of brightness (i.e., white) it contains.

HEARING.—Hearing is also a distance sense. The action of its stimulus is mechanical, which is to say that the vibrations produced in the air by the sounding body are finally transmitted by the mechanism of the middle ear to the inner ear. Here the impulse is conveyed through the liquid of the internal ear to the nerve endings as so many tiny blows, which produce the nerve current carried to the brain by the auditory nerve.

The sensation of hearing, like that of sight, gives us two qualities: namely, tones with their accompanying pitch and timbre, and noises. Tones, or musical sounds, are produced by isochronous or equal-timed vibrations; thus C of the first octave is produced by 256 vibrations a second, and if this tone is prolonged the vibration rate will continue uniformly the same. Noises, on the other hand, are produced by vibrations which have no uniformity of vibration rate. The ear's sensibility to pitch extends over about seven octaves. The seven-octave piano goes down to 27-1/2 vibrations and reaches up to 3,500 vibrations. Notes of nearly 50,000 vibrations can be heard by an average ear, however, though these are too painfully shrill to be musical. Taking into account this upper limit, the range of the ear is about eleven octaves. The ear, having given us loudness of tones, which depends on the amplitude of the vibrations, pitch, which depends on the rapidity of the vibrations, and timbre, or quality, which depends on the complexity of the vibrations, has no further qualities of sound to reveal.

TASTE.—The sense of taste is located chiefly in the tongue, over the surface of which are scattered many minute taste-bulbs. These can be seen as small red specks, most plentifully distributed along the edges and at the tip of the tongue. The substance tasted must be in solution, and come in contact with the nerve endings. The action of the stimulus is chemical.

The sense of taste recognizes the four qualities of sour, sweet, salt, and bitter. Many of the qualities which we improperly call tastes are in reality a complex of taste, smell, touch, and temperature. Smell contributes so largely to the sense of taste that many articles of food become "tasteless" when we have a catarrh, and many nauseating doses of medicine can be taken without discomfort if the nose is held. Probably none of us, if we are careful to exclude all odors by plugging the nostrils with cotton, can by taste distinguish between scraped apple, potato, turnip, or beet, or can tell hot milk from tea or coffee of the same temperature.

SMELL.—In the upper part of the nasal cavity lies a small brownish patch of mucous membrane. It is here that the olfactory nerve endings are located. The substance smelled must be volatile, that is, must exist in gaseous form, and come in direct contact with the nerve endings. Chemical action results in a nerve current.

The sensations of smell have not been classified so well as those of taste, and we have no distinct names for them. Neither do we know how many olfactory qualities the sense of smell is capable of revealing. The only definite classification of smell qualities is that based on their pleasantness or the opposite. We also borrow a few terms and speak of sweet or fragrant odors and fresh or close smells. There is some evidence when we observe animals, or even primitive men, that the human race has been evolving greater sensibility to certain odors, while at the same time there has been a loss of keenness of what we call scent.

VARIOUS SENSATIONS FROM THE SKIN.—The skin, besides being a protective and excretory organ, affords a lodging-place for the end-organs giving us our sense of pressure, pain, cold, warmth, tickle, and itch. Pressure seems to have for its end-organ the hair-bulbs of the skin; on hairless regions small bulbs called the corpuscles of Meissner serve this purpose. Pain is thought to be mediated by free nerve endings. Cold depends on end-organs called the bulbs of Krause; and warmth on the Ruffinian corpuscles.

Cutaneous or skin sensation may arise from either mechanical stimulation, such as pressure, a blow, or tickling, from thermal stimulation from hot or cold objects, from electrical stimulation, or from the action of certain chemicals, such as acids and the like. Stimulated mechanically, the skin gives us but two sensation qualities, pressure and pain. Many of the qualities which we commonly ascribe to the skin sensations are really a complex of cutaneous and muscular sensations. Contact is light pressure. Hardness and softness depend on the intensity of the pressure. Roughness and smoothness arise from interrupted and continuous pressure, respectively, and require movement over the rough or smooth surface. Touch depends on pressure accompanied by the muscular sensations involved in the movements connected with the act. Pain is clearly a different sensation from pressure; but any of the cutaneous or muscular sensations may, by excessive stimulation, be made to pass over into pain. All parts of the skin are sensitive to pressure and pain; but certain parts, like the finger tips, and the tip of the tongue, are more highly sensitive than others. The skin varies also in its sensitivity to heat and cold. If we take a hot or a very cold pencil point and pass it rather lightly and slowly over the skin, it is easy to discover certain spots from which a sensation of warmth or of cold flashes out. In this way it is possible to locate the end-organs of temperature very accurately.



THE KINAESTHETIC SENSES.—The muscles, tendons, and joints also give rise to perfectly definite sensations, but they have not been named as have the sensations from most of the other end-organs. Weight is the most clearly marked of these sensations. It is through the sensations connected with movements of muscles, tendons, and joints that we come to judge form, size, and distance.

THE ORGANIC SENSES.—Finally, to the sensations mentioned so far must be added those which come from the internal organs of the body. From the alimentary canal we get the sensations of hunger, thirst, and nausea; from the heart, lungs, and organs of sex come numerous well-defined but unnamed sensations which play an important part in making up the feeling-tone of our daily lives.

Thus we see that the senses may be looked upon as the sentries of the body, standing at the outposts where nature and ourselves meet. They discover the qualities of the various objects with which we come in contact and hand them over to the mind in the form of sensations. And these sensations are the raw material out of which we begin to construct our material environment. Only as we are equipped with good organs of sense, especially good eyes and ears, therefore, are we able to enter fully into the wonderful world about us and receive the stimuli necessary to our thought and action.

4. PROBLEMS IN OBSERVATION AND INTROSPECTION

1. Observe a schoolroom of children at work with the aim of discovering any that show defects of vision or hearing. What are the symptoms? What is the effect of inability to hear or see well upon interest and attention?

2. Talk with your teacher about testing the eyes and ears of the children of some school. The simpler tests for vision and hearing are easily applied, and the expense for material almost nothing. What tests should be used? Does your school have the test card for vision?

3. Use a rotator or color tops for mixing discs of white and black to produce different shades of gray. Fix in mind the gray made of half white and half black; three-fourths white and one-fourth black; one-fourth-white and three-fourths black.

4. In the same way mix the two complementaries yellow and blue to produce a gray; mix red and green in the same way. Try various combinations of the four fundamental colors, and discover how different colors are produced. Seek for these same colors in nature—sky, leaves, flowers, etc.

5. Take a large wire nail and push it through a cork so that it can be handled without touching the metal with the fingers. Now cool it in ice or very cold water, then dry it and move the point slowly across the back of the hand. Do you feel occasional thrills of cold as the point passes over a bulb of Krause? Heat the nail with a match flame or over a lamp, and perform the same experiment. Do you feel the thrills of heat from the corpuscles of Ruffini?

6. Try stopping the nostrils with cotton and having someone give you scraped apple, potato, onion, etc., and see whether, by taste alone, you can distinguish the difference. Why cannot sulphur be tasted?



CHAPTER VII

PERCEPTION

No young child at first sees objects as we see them, or hears sounds as we hear them. This power, the power of perception, is a gradual development. It grows day by day out of the learner's experience in his world of sights and sounds, and whatever other fields his senses respond to.

1. THE FUNCTION OF PERCEPTION

NEED OF KNOWING THE MATERIAL WORLD.—It is the business of perception to give us knowledge of our world of material objects and their relations in space and time. The material world which we enter through the gateways of the senses is more marvelous by far than any fairy world created by the fancy of story-tellers; for it contains the elements of all they have conceived and much more besides. It is more marvelous than any structure planned and executed by the mind of man; for all the wonders and beauties of the Coliseum or of St. Peter's existed in nature before they were discovered by the architect and thrown together in those magnificent structures. The material advancement of civilization has been but the discovery of the objects, forces, and laws of nature, and their use in inventions serviceable to men. And these forces and laws of nature were discovered only as they were made manifest through objects in the material world.

The problem lying before each individual who would enter fully into this rich world of environment, then, is to discover at first hand just as large a part of the material world about him as possible. In the most humble environment of the most uneventful life is to be found the material for discoveries and inventions yet undreamed of. Lying in the shade of an apple tree under the open sky, Newton read from a falling apple the fundamental principles of the law of gravitation which has revolutionized science; sitting at a humble tea table Watt watched the gurgling of the steam escaping from the kettle, and evolved the steam engine therefrom; with his simple kite, Franklin drew down the lightning from the clouds, and started the science of electricity; through studying a ball, the ancient scholars conceived the earth to be a sphere, and Columbus discovered America.

THE PROBLEM WHICH CONFRONTS THE CHILD.—Well it is that the child, starting his life's journey, cannot see the magnitude of the task before him. Cast amid a world of objects of whose very existence he is ignorant, and whose meaning and uses have to be learned by slow and often painful experience, he proceeds step by step through the senses in his discovery of the objects about him. Yet, considered again, we ourselves are after all but a step in advance of the child. Though we are somewhat more familiar with the use of our senses than he, and know a few more objects about us, yet the knowledge of the wisest of us is at best pitifully meager compared with the richness of nature. So impossible is it for us to know all our material environment, that men have taken to becoming specialists. One man will spend his life in the study of a certain variety of plants, while there are hundreds of thousands of varieties all about him; another will study a particular kind of animal life, perhaps too minute to be seen with the naked eye, while the world is teeming with animal forms which he has not time in his short day of life to stop to examine; another will study the land forms and read the earth's history from the rocks and geological strata, but here again nature's volume is so large that he has time to read but a small fraction of the whole. Another studies the human body and learns to read from its expressions the signs of health and sickness, and to prescribe remedies for its ills; but in this field also he has found it necessary to divide the work, and so we have specialists for almost every organ of the body.

2. THE NATURE OF PERCEPTION

HOW A PERCEPT IS FORMED.—How, then, do we proceed to the discovery of this world of objects? Let us watch the child and learn the secret from him. Give the babe a ball, and he applies every sense to it to discover its qualities. He stares at it, he takes it in his hands and turns it over and around, he lifts it, he strokes it, he punches it and jabs it, he puts it to his mouth and bites it, he drops it, he throws it and creeps after it. He leaves no stone unturned to find out what that thing really is. By means of the qualities which come to him through the avenues of sense, he constructs the object. And not only does he come to know the ball as a material object, but he comes to know also its uses. He is forming his own best definition of a ball in terms of the sensations which he gets from it and the uses to which he puts it, and all this even before he can name it or is able to recognize its name when he hears it. How much better his method than the one he will have to follow a little later when he goes to school and learns that "A ball is a spherical body of any substance or size, used to play with, as by throwing, kicking, or knocking, etc.!"

THE PERCEPT INVOLVES ALL RELATIONS OF THE OBJECT.—Nor is the case in the least different with ourselves. When we wish to learn about a new object or discover new facts about an old one, we do precisely as the child does if we are wise. We apply to it every sense to which it will afford a stimulus, and finally arrive at the object through its various qualities. And just in so far as we have failed to use in connection with it every sense to which it can minister, just in that degree will we have an incomplete perception of it. Indeed, just so far as we have failed finally to perceive it in terms of its functions or uses, in that far also have we failed to know it completely. Tomatoes were for many years grown as ornamental garden plants before it was discovered that the tomatoes could minister to the taste as well as to the sight. The clothing of civilized man gives the same sensation of texture and color to the savage that it does to its owner, but he is so far from perceiving it in the same way that he packs it away and continues to go naked. The Orientals, who disdain the use of chairs and prefer to sit cross-legged on the floor, can never perceive a chair just as we do who use chairs daily, and to whom chairs are so saturated with social suggestions and associations.

THE CONTENT OF THE PERCEPT.—The percept, then, always contains a basis of sensation. The eye, the ear, the skin or some other sense organ must turn in its supply of sensory material or there can be no percept. But the percept contains more than just sensations. Consider, for example, your percept of an automobile flashing past your windows. You really see but very little of it, yet you perceive it as a very familiar vehicle. All that your sense organs furnish is a more or less blurred patch of black of certain size and contour, one or more objects of somewhat different color whom you know to be passengers, and various sounds of a whizzing, chugging or roaring nature. Your former experience with automobiles enables you to associate with these meager sensory details the upholstered seats, the whirling wheels, the swaying movement and whatever else belongs to the full meaning of a motor car.

The percept that contained only sensory material, and lacked all memory elements, ideas and meanings, would be no percept at all. And this is the reason why a young child cannot see or hear like ourselves. It lacks the associative material to give significance and meaning to the sensory elements supplied by the end-organs. The dependence of the percept on material from past experience is also illustrated in the common statement that what one gets from an art exhibit or a concert depends on what he brings to it. He who brings no knowledge, no memory, no images from other pictures or music will secure but relatively barren percepts, consisting of little besides the mere sensory elements. Truly, "to him that hath shall be given" in the realm of perception.

THE ACCURACY OF PERCEPTS DEPENDS ON EXPERIENCE.—We must perceive objects through our motor response to them as well as in terms of sensations. The boy who has his knowledge of a tennis racket from looking at one in a store window, or indeed from handling one and looking it over in his room, can never know a tennis racket as does the boy who plays with it on the court. Objects get their significance not alone from their qualities, but even more from their use as related to our own activities.

Like the child, we must get our knowledge of objects, if we are to get it well, from the objects themselves at first hand, and not second hand through descriptions of them by others. The fact that there is so much of the material world about us that we can never hope to learn it all, has made it necessary to put down in books many of the things which have been discovered concerning nature. This necessity has, I fear, led many away from nature itself to books—away from the living reality of things to the dead embalming cases of words, in whose empty forms we see so little of the significance which resides in the things themselves. We are in danger of being satisfied with the forms of knowledge without its substance—with definitions contained in words instead of in qualities and uses.

NOT DEFINITIONS, BUT FIRST-HAND CONTACT.—In like manner we come to know distance, form and size. If we have never become acquainted with a mile by actually walking a mile, running a mile, riding a bicycle a mile, driving a horse a mile, or traveling a mile on a train, we might listen for a long time to someone tell how far a mile is, or state the distance from Chicago to Denver, without knowing much about it in any way except word definitions. In order to understand a mile, we must come to know it in as many ways as possible through sense activities of our own. Although many children have learned that it is 25,000 miles around the earth, probably no one who has not encircled the globe has any reasonably accurate notion just how far this is. For words cannot take the place of perceptions in giving us knowledge. In the case of shorter distances, the same rule holds. The eye must be assisted by experience of the muscles and tendons and joints in actually covering distance, and learn to associate these sensations with those of the eye before the eye alone can be able to say, "That tree is ten rods distant." Form and size are to be learned in the same way. The hands must actually touch and handle the object, experiencing its hardness or smoothness, the way this curve and that angle feels, the amount of muscular energy it takes to pass the hand over this surface and along that line, the eye taking note all the while, before the eye can tell at a glance that yonder object is a sphere and that this surface is two feet on the edge.

3. THE PERCEPTION OF SPACE

Many have been the philosophical controversies over the nature of space and our perception of it. The psychologists have even quarreled concerning whether we possess an innate sense of space, or whether it is a product of experience and training. Fortunately, for our present purpose we shall not need to concern ourselves with either of these controversies. For our discussion we may accept space for what common sense understands it to be. As to our sense of space, whatever of this we may possess at birth, it certainly has to be developed by use and experience to become of practical value. In the perception of space we must come to perceive distance, direction, size, and form. As a matter of fact, however, size is but so much distance, and form is but so much distance in this, that, or the other direction.

THE PERCEIVING OF DISTANCE.—Unquestionably the eye comes to be our chief dependence in determining distance. Yet the muscle and joint senses give us our earliest knowledge of distance. The babe reaches for the moon simply because the eye does not tell it that the moon is out of reach. Only as the child reaches for its playthings, creeps or walks after them, and in a thousand ways uses its muscles and joints in measuring distance, does the perception of distance become dependable.