Читать книгу Child Psychology I: Development in the First Four Years - Vilhelm Rasmussen - Страница 6

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The very possibility of instituting psycho-physical experiments rests on the close relation of dependency which exists between the activities of the soul and the bodily or “physical” activities. Whatever view one may hold of the relation between “soul” and body, whether one is a materialist, an idealist, an adherent of the identity-hypothesis,^[1] or of other hypotheses, one is obliged to admit the fact that the phenomena of the soul’s life always correspond to manifestations of physical life in the nervous system. We know no life of the soul which is not linked to a nervous system in working order; and whenever anything happens in the soul of a person, it is always possible to detect signs of fatigue. There is absolutely no sharp line between the psychical and the physical, as ordinary language would lead one to suppose. “There is no boundary,” says Meumann, “between bodily and mental work; all bodily work is at the same time mental ...; all mental work is at the same time bodily, accompanied by parallel physical processes in the brain and (the other parts of) the nervous system. Consequently one can in many cases measure manifestations of the soul’s life indirectly by means of the accompanying physical activities.”

In general, so it has further been observed, the development of the nervous system and the development of the soul keep pace with each other. Every check to the development of the brain causes defective development of the soul life, and microcephalics^[2] may stand on a level much beneath that of the most intelligent animals. But small children have a very slightly developed nervous system; and it is only gradually, as this system attains higher and higher stages of development, that the child becomes able to exhibit the corresponding manifestations of soul life.

The nervous system, as is well known, consists of nerves, brain, spinal marrow, and scattered nerve-ganglia; but the structural element is the nerve-cell. Like most other living animal-cells, it consists of protoplasm with a nucleus; but there proceed from the protoplasm of a nerve-cell a number of highly ramified threads, called dendrites, and a single long thread which is called the nerve-thread, or, more accurately, the axial cylinder of a nerve-thread. The dendrites connect the protoplasm of the different nerve-cells, in such a way that a large number of cells is collected into a co-operating aggregate. The axial cylinders of the nerve-threads, on the other hand, effect connection between the nerve-cells and the organs of sense, the glands, the muscles, and so on, or else they connect cell-aggregates in the brain or spinal marrow which lie at a considerable distance from each other. As a rough analogy, one may compare the whole nervous system with the telephone network of a town. The power stations correspond to the cell-aggregates in the brain and spinal marrow; the telephone wires correspond to the nerve-threads. Just as the telephone wires underground are collected into cables, in which each separate wire is insulated from the others, so that the current may not be distributed over several wires, so the axial cylinders of the nerve-threads are also insulated and collected into cables. The axial cylinders are in fact enclosed in a casing, called the medullary sheath; and a “nerve” consists of a vast number of axial cylinders, each with its own, medullary sheath. If the medullary sheath is absent the nerve-thread cannot function, because the unknown “nerve-force” is not confined by insulation to a single axial cylinder. If the protoplasm of the nerve-cell is not fully formed, then for that reason it cannot function either. On the other hand, if the greater protoplasm mass and the nerve-thread are both fully formed, the cell can begin to function; but that is by no means the same thing as saying that its capacity to function is fully developed. The rule holds for nerve-cells as well as for other organs that only practice makes the master.

It is, however, not the case that every activity in the nerve-cells is accompanied by higher manifestations of the soul life which we are conscious of. Many of our organs, for example, the heart, work altogether “mechanically,” as long as everything goes on as it should. Such activities are governed by special nerve-ganglia with their threads. Many other movements, for example, those of the iris when the pupil is contracted or expanded, also proceed mechanically, but as a consequence of an external influence. Other actions are quite certainly conscious, but only in a very slight degree; and the power of executing them is inborn, so that they quickly become automatic. This is the case, for example, with the infant’s act of sucking. But other actions require long practice and persistent thought, even after great facility has been acquired, for example, the solving of mathematical problems. The manifestations of the soul life are thus of many different kinds.

Actions are divided according to their causes and peculiarities into several groups.

The simplest are the spontaneous. They are made known by movements in which external influence plays practically no part, but which arise through discharge of the energy accumulated in the nerve-centres as a result of abundant blood-supply and vigorous nutrition.^[3] All such movements take place without thought, for example, a baby’s kicking.

Another kind of unconscious manifestations of soul life are the reflexes. They have their cause in an external influence. For example, one blinks purely by reflex action, without consideration, if some one thrusts a clenched fist quickly in front of one’s eyes.

A third kind of lower, involuntary manifestations of soul life are the instincts; but instinctive actions presuppose “probably always a strong want”; and it is assumed that it arouses a highly pleasurable feeling to give way to the want and satisfy it. Besides, the power of performing instinctive actions is inherited, even if practice can perfect the execution; for an instinctive action can be performed the first time that it is serviceable to life. On the other hand, it is a common feature in reflexes and instinctive acts that both require an external influence. The chicken, for example, must see the grains before its innate instinct to eat grains can manifest itself; but as soon as the chicken is hatched it can both see grains and eat them.

From these manifestations of soul life, all of which come under the head of involuntary movements, there are transitions to the higher and the highest manifestations, which proceed with full consciousness. In the desires, that which leads to action is the idea of something. The thirsty man imagines something to drink and afterwards seeks to procure it for himself. “Conscious Life reaches its highest development where deliberation is possible in the interval between the impression (the incentive) and the action, without the loss of the power of energetic decision, and where at the same time ideas and feelings can arise and be preserved in a certain independence of the practical needs,” says Høffding in his Psykologi.

The lower manifestations of soul life, the spontaneous, the reflexive, the instinctive, have the very greatest importance for our life; but they are not much thought about because they are so ordinary and proceed unnoticed or even all but imperceptibly. It is not till irregularity enters into the activities that attention is drawn; and when the case becomes serious one goes to the doctor.

Who gives a thought to the fact that the pupil of the eye is expanded or contracted quite mechanically, according as the intensity of the light is diminished or increased? But if anything went wrong with the pupil’s changes, one would soon be on the way to the doctor. The involuntary manifestations of soul life are among the activities which condition our life in the very highest degree. They are therefore innate when they are specially indispensable: otherwise, they are acquired as “habits” and confirmed by exercise. These acquired reflexes also as a rule attract but little attention, since they act automatically once practice has produced facility. But during the process of acquisition the case is otherwise. A little child is a long time in learning to dress itself; but the adult can meditate on a new form of calculating machine while he is buttoning his coat. Practice in reading, writing, violin-playing, and so on gives a great deal of trouble; but when one is efficient the tribulations are forgotten. As a rule the most difficult and tedious to acquire are the reflexes or habits which do not depend on inborn, instinctive inclinations, but, on the contrary, require set purpose and will, or even compulsion. A child which learns to play an instrument without pleasure, under parental compulsion, is extraordinarily long in acquiring the dexterity which is necessary before the movements can proceed as pure reflexes.

Simultaneously with the provocation of reflex acts by external influences there are also probably aroused, at any rate in many cases, vague feelings of pleasure or displeasure, comfort or discomfort. This is perhaps not at all the case with such reflexes as the change in the pupil, but on the other hand it is pretty certainly so with such reflexes as the heart-beat, respiration, the excreting activity of the glands which supply the digestive juices; for when all is well with these and similar vital activities one has a feeling of well-being, while disturbance produces discomfort or even pain. There is thus no gulf between the unconscious manifestations of soul life and the conscious life proper. It is difficult or even impossible to draw a determinate boundary line; but the child begins its individual soul life with the very simplest spontaneous actions and reflexes, and rises by gradual steps to higher and higher forms of soul life. To follow this development is the task of child psychology; the results obtained can then be applied in many ways—not least in the service of education.

[1]	On this see H. Høffding, Psykologi; and K. Kroman, Tænkeog Sjœlelære.

[2]	That is, persons with too small a brain.

[3]	H. Høffding, Psykologi, 6th ed., p. 119.