Pa.s.sing to a consideration of the senses as organs through which the mind is made aware of the concrete world, it is to be noted that a number of factors precede the image, or mental interpretation, of the impression. When, for instance, the mind becomes cognizant of a musical note, an a.n.a.lysis of the whole process reveals the following factors:
1. The concrete object, as the vibrating string of a violin.
2. Sound waves proceeding from the vibrating object to the sense organ.
3. The organ of sense--the ear.
[Ill.u.s.tration]
4. The nerves--cells and fibres involved in receiving and conveying the sense stimulus.
5. The interpreting cells.
6. The reacting mind, which interprets the impression as an image of sound.
The different factors are somewhat arbitrarily ill.u.s.trated in the accompanying diagram, the arrows indicating the physical stimulation and the conscious response:
Of the six factors involved in the sensation, 1 and 2 are purely physical and belong to the science of acoustics; 3, 4, and 5 are physiological; 6 is conscious, or psychological. It is because they always involve the immediate presence of some physical object, that the sensation elements involved in ordinary perception are spoken of as immediate, or presentative, elements of knowledge.
CLa.s.sIFICATION OF SENSATIONS
Our various sensations are usually divided into three cla.s.ses as follows:
1. Sensations of the special senses, including: sight, sound, touch (including temperature), taste, and smell.
2. Motor, or muscular, sensations.
3. Organic sensations.
=Sensations of the Special Senses.=--As a study of the five special senses has been made by the student-teacher under the heading of physiology, no attempt will be made to explain the structure of these organs. It must be noted, however, that not all senses are equally capable of distinguishing differences in quality. For example, it seems quite beyond our power to recall the tastes and odours of the various dishes of which we may have partaken at a banquet, while on the other hand we may recall distinctly the visual appearance of the room and the table. It is worthy of note, also, that in the case of smell, animals are usually much more discriminative than man. Certain of our senses are, therefore, much more intellectual than others. By this is meant that for purposes of distinguishing the objects themselves, and for providing the mind with available images as materials for further thought, our senses are by no means equally effective. Under this heading the special senses are cla.s.sified as follows:
Higher Intellectual Senses: sight, hearing, touch.
Lower Intellectual Senses: taste and smell.
=Muscular Sensations.=--Under motor, or muscular, sensations are included the feelings which accompany consciousness of muscular exertion, or movement. In distinction from the other sense organs, the muscles are stimulated by having nervous energy pa.s.s outward over the motor nerves to the muscles. As the muscles are thus stimulated to movement, sensory nerves in turn convey inward from the muscles sensory impressions resulting from these movements. The important sensations connected with muscular action are those of strain, force, and resistance, as in lifting or pushing. By means of these motor sensations, joined with the sense of touch, the individual is able to distinguish especially weight, position, and change of position. In connection with the muscular sense, may be recalled that portion of the Montessori apparatus known as the weight tablets. These wooden tablets, it will be noted, are designed to educate the muscular sense to distinguish slight differences in weight. The muscular sense is chiefly important, however, in that delicate distinctions of pressure, movement, and resistance must be made in many forms of manual expression. The interrelation between sensory impression and motor impulse within the nervous system, as ill.u.s.trated in the figures on page 200, is already understood by the reader. For an adequate conscious control of movements, especially when one is engaged in delicate handwork, as painting, modelling, wood-work, etc., there must be an ability to perceive slight differences in strain, pressure, and movement. Moreover, the most effective means for developing the muscular sense is through the expressive exercises referred to above.
=Organic Sensations.=--The organic sensations are those states of consciousness that arise in connection with the processes going on within the organism, as circulation of the blood, digestion; breathing, or respiration; hunger; thirst; etc. The significance of these sensations lies in the fact that they reveal to consciousness any disturbances in connection with the vital processes, and thus enable the individual to provide for the preservation of the organism.
EDUCATION OF THE SENSES
=Importance.=--When it is considered that our general knowledge must be based on a knowledge of individuals, it becomes apparent that children should, through sense observation, learn as fully as possible the various qualities of the concrete world. Only on this basis can they build their more general and abstract forms of knowledge. For this reason the child in his study of objects should, so far as safety permits, bring all of his senses to bear upon them and distinguish as clearly as possible all their properties. By this means only can he really know the attributes of the objects const.i.tuting his environment.
Moreover, without such a full knowledge of the various properties and qualities of concrete objects, he is not in a position to turn them fully to his own service. It is by distinguishing the feeling of the flour, that the cook discovers whether it is suited for bread-making or pastry. It is by noting the texture of the wood, that the artisan can decide its suitability for the work in hand. In fine, it was only by noting the properties of various natural objects that man discovered their social uses.
=How to be Effected.=--One of the chief defects of primary education in the past has been a tendency to overlook the importance of giving the child an opportunity to exercise his senses in discovering the properties of the objects const.i.tuting his environment. The introduction of the kindergarten, objective methods of teaching, nature study, school gardening, and constructive occupations have done much, however, to remedy this defect. One of the chief claims in favour of the so-called Montessori Method is that it provides especially for an education of the senses. In doing this, however, it makes use of arbitrarily prepared materials instead of the ordinary objects const.i.tuting the child"s natural environment. The one advantage in this is that it enables the teacher to grade the stimulations and thus exercise the child in making series of discriminations, for instance, a series of colours, sounds, weights, sizes, etc. Notwithstanding this advantage, however, it seems more pedagogical that the child should receive this needful exercise of the senses by being brought into contact with the actual objects const.i.tuting his environment, as is done in nature study, constructive exercises, art, etc.
=Dangers of Neglecting the Senses.=--The former neglect of an adequate exercise of the senses during the early education of the child was evidently unpedagogical for various reasons. As already noted, other forms of acquiring knowledge, such as constructive imagination, induction, and deduction, must rest primarily upon the acquisitions of sense perception. Moreover, it is during the early years of life that the plasticity and retentive power of the nervous system will enable the various sense impressions to be recorded for the future use of the mind.
Further, the senses themselves during these early years show what may be termed a hunger for contact with the world of concrete objects, and a corresponding distaste for more abstract types of experience.
=Learning Through all the Senses.=--In recognizing that the process of sense perception const.i.tutes a learning process, or is one of the modes by which man enters into new experience, the teacher should further understand that the same object may be interpreted through different senses. For example, when a child studies a new bird, he may note its form and colour through the eye, he may recognize the feeling and the outline through muscular and touch sensations, he may discover its song through the ear, and may give muscular expression to its form in painting or modelling. In the same way, in learning a figure or letter, he may see its form through the eye, hear its sound through the ear, make the sound and trace the form by calling various muscles into play, and thus secure a number of muscular sensations relative to the figure or letter. Since all these various experiences will be co-ordinated and retained within the nervous system, the child will not only know the object better, but will also be able to recall more easily any items of knowledge concerning it, on account of the larger number of connections established within the nervous system. One chief fact to be kept in mind by the teacher, therefore, in using the method of sense perception, is to have the pupil study the object through as many different senses as possible, and especially through those senses in which his power of discrimination and recall seems greatest.
=Use of Different Images in Teaching.=--The importance to the teacher of an intimate knowledge of different types of imagery and of a further acquaintance with the more prevailing images of particular pupils, is evident in various ways. In the first place, different school subjects may appeal more especially to different types of imagery. Thus a study of plants especially involves visual, or sight, images; a study of birds, visual and auditory images; oral reading and music, auditory images; physical training, motor images; constructive work, visual, tactile, and motor images; a knowledge of weights and measures, tactile and motor images. On account of a native difference in forming images, also, one pupil may best learn through the eye, another through the ear, a third through the muscles, etc. In learning the spelling of words, for example, one pupil may require especially to visualize the word, another to hear the letters repeated in their order, and a third to articulate the letters by the movement of the organs of speech, or to trace them in writing. In choosing ill.u.s.trations, also, the teacher will find that one pupil best appreciates a visual ill.u.s.tration, a second an auditory ill.u.s.tration, etc. Some young pupils, for instance, might best appreciate a pathetic situation through an appeal to such sensory images as hunger and thirst.
=An Ill.u.s.tration.=--The wide difference in people"s ability to interpret sensuous impressions is well exemplified in the case of sound stimuli.
Every one whose ear is physically perfect seems able to interpret a sound so far as its mere quality and quant.i.ty are concerned. In the case of musical notes, however, the very greatest difference is found in the ability of different individuals to distinguish pitch. So also the distinguishing of distance and direction in relation to sound is an acquired ability, in which different people will greatly differ.
Finally, to interpret the external relations involved in the sound, that is, whether the cry is that of an insect or a bird, or, if it is the former, from what kind of bird the sound is proceeding, this evidently is a phase of sense interpretation in which individuals differ very greatly. Yet an adequate development of the sense of hearing might be supposed to give the individual an ability to interpret his surroundings in all these ways.
=Power of Sense Perception Limited: A. By Interest.=--It should be noted, however, that so far as our actual life needs are concerned, there is no large demand for an all-round ability to interpret sensuous impressions. For practical purposes, men are interested in different objects in quite different ways. One is interested in the colour of a certain wood, another in its smoothness, a third in its ability to withstand strain, while a fourth may even be interested in more hidden relations, not visible to the ordinary sense. This will justify one in ignoring entirely qualities in the object which are of the utmost importance to others. From such a practical standpoint, it is evidently a decided gain that a person is not compelled to see everything in an object which its sensuous attributes might permit one to discover in it.
In the case of the man with the so-called untrained sense, therefore, it is questionable whether the failure to see, hear, etc., is in many cases so much a lack of ability to use the particular sense, as it is a lack of practical interest in this phase of the objective world. In such processes as induction and deduction, also, it is often the external relations of objects rather than their sensory qualities that chiefly interest us. Indeed, it is sometimes claimed that an excessive amount of mere training in sense discrimination might interfere with a proper development of the higher mental processes.
=B. By Knowledge.=--From what has been discovered regarding the learning process, it is evident that the development of any sense, as sight, sound, touch, etc., is not brought about merely by exercising the particular organ. It has been learned, for instance, that the person who is able to observe readily the plant and animal life as he walks through the forest, possesses this skill, not because his physical eye, but because his mind, has been prepared to see these objects. In other words, it is because his knowledge is active along such lines that his eye beholds these particular things. The chief reason, therefore, why the exercise of any sense organ develops a power to perceive through that sense, is that the exercise tends to develop in the individual the knowledge and interest which will cause the mind to react easily and effectively on that particular cla.s.s of impressions. A sense may be considered trained, therefore, to the extent to which the mind acquires knowledge of, and interest in, the objective elements.
CHAPTER XXVI
MEMORY AND APPERCEPTION
=Nature of Memory.=--Mention has been made of the retentive power of the nervous system, and of a consequent tendency for mental images to revive, or _re-present_, themselves in consciousness. It must now be noted that such a re-presentation of former experiences is frequently accompanied with a distinct recognition that the present image or images have a definite reference to past time. In other words, the present mental fact is able to be placed in the midst of other events believed to make up some portion of our past experience. Such an ideal revival of a past experience, together with a recognition of the fact that it formerly occurred within our experience, is known as an act of memory.
=Neural Conditions of Memory.=--When any experience is thus reproduced, and recognized as a reproduction of a previous experience, there is physiologically a transmission of nervous energy through the same brain centres as were involved in the original experience. The mental reproduction of any image is conditioned, therefore, by the physical reproduction of a nervous impulse through a formerly established path.
That this is possible is owing to the susceptibility of nervous tissue to take on habit, or to retain as permanent modifications, all impressions received. From this it is evident that when we say we retain certain facts in our mind, the statement is not in a sense true; for there is no knowledge stored up in consciousness as so many ideas. The statement is true, therefore, only in the sense that the mind is able to bring into consciousness a former experience by reinstating the necessary nervous impulses through the proper nervous arcs. What is actually retained, however, is the tendency to reinstate nervous movements through the same paths as were involved in the original experience. Although, therefore, retention is usually treated as a factor in memory, its basis is, in reality, physiological.
=Memory Distinguished from Apperception.=--The distinguishing characteristics of memory as a re-presentation in the mind of a former experience is evidently the mental att.i.tude known as recognition.
Memory, in other words, always implies a belief that the present mental state really represents a fact, or event, which formed a part of our past experience. In the apperceptive process as seen in an ordinary process of learning, on the other hand, although it seems to involve a re-presentation of former mental images in consciousness, this distinct reference of the revived imagery to past time is evidently wanting.
When, for instance, the mind interprets a strange object as a pear-shaped, thin-rinded, many-seeded fruit, all these interpreting ideas are, in a sense, revivals of past experience; yet none carry with them any distinct reference to past time. In like manner, when I look at an object of a certain form and colour and say that it is a sweet apple, it is evidently owing to past experience that I can declare that particular object to be sweet. It is quite clear, however, that in such a case there is no distinct reference of the revived image of sweetness to any definite occurrence in one"s former experience. Such an apperceptive revival, or re-presentation of past experience, because it includes merely a representation of mental images, but fails to relate them to the past, cannot be cla.s.sed as an act of memory.
=But Involves Apperceptive Process.=--While, however, the mere revival of old knowledge in the apperceptive process does not const.i.tute an act of memory, memory is itself only a special phase of the apperceptive process. When I think of a particular anecdote to-day, and say I remember having the same experience on Sunday evening last, the present mental images cannot be the very same images as were then experienced.
The former images belonged to the past, while those at present in consciousness are a new creation, although dependent, as we have seen, upon certain physiological conditions established in the past. In an act of memory, therefore, the new presentation, like all new presentations, must be interpreted in terms of past experience, or by an apperceiving act of attention. Whenever in this apperceptive act there is, in addition to the interpretation, a further feeling, or sense, of familiarity, the presentation is accepted by the mind as a reproduction from past experience, or is recognized as belonging to the past. When, on the way down the street, for instance, impressions are received from a pa.s.sing form, and a resulting act of apperceiving attention, besides reading meaning into them, awakens a sense of familiarity, the face is recognized as one seen on a former occasion. Memory, therefore, is a special mode of the apperceptive process of learning, and includes, in addition to the interpreting of the new through the old, a belief that there is an ident.i.ty between the old and the new.
FACTORS OF MEMORY
In a complete example of memory the following factors may be noted:
1. The original presentation--as the first perception of an object or scene, the reading of a new story, the hearing of a particular voice, etc.
2. Retention--this involves the permanent changes wrought in the nervous tissue as a result of the presentation or learning process and, as mentioned above, is really physiological.
3. Recall--this implies the re-establishment of the nervous movements involved in the original experiences and an accompanying revival of the mental imagery.
4. Recognition--under this heading is included the sense of familiarity experienced in consciousness, and the consequent belief that the present experience actually occurred at some certain time as an element in our past experience.
CONDITIONS OF MEMORY