Characteristics of the Illustrative Method.—In many cases it is impossible or impracticable to bring the concrete object into the school-room, or to take the pupils to see it outside. In such cases, somewhat the same result may be obtained by means of some form of graphic illustration of the object, as a picture, sketch, diagram, map, model, lantern slide, etc. The graphic representation of an object may present to the eye most of the characteristics that the actual object would. For this reason pictures are being more and more used in teaching, though it is a question whether teachers make as good use of the pictures of the text-book, in geography for instance, as might be made.
Illustrative Method Involves Imagination.—In the illustrative method, however, the pupil, instead of being able to apply directly former knowledge obtained through the senses, in interpreting the actual object, must make use of his imagination to bridge over the gulf between the actual object and the representation. When, for example, the child is called upon to form his conception of the earth with its two hemispheres through its representation on a globe, the knowledge will become adequate only as the child's imagination is able to picture in his mind the actual object out of his own experience of land, water, form, and space, in harmony with the mere suggestions offered by the model. It is evident, for the above reason, that the illustrative method often demands more from the pupil than does the more concrete objective method. For instance, the child who is able to see an actual mountain, lake, canal, etc., is far more likely to obtain an accurate idea of these, than the student who learns them by means of illustrations. The cause for this lies mainly in the failure of the child to form a perfect image of the real object through the exercise of his imagination. In fact it sometimes happens that he makes very little use of his imagination, his mental picture of the real object differing little from the model placed before him. The writer was informed of a case in which a teacher endeavoured to give some young pupils a knowledge of the earth by means of a large school globe. When later the children were questioned thereon, it was discovered that their earth corresponded in almost every particular with the large globe in the school. The successful use of the illustrative method, therefore, demands from the teacher a careful test by the question and answer method, to see that the learner has properly bridged over, through his imagination, the gulf separating the actual object from its illustration. For this reason an acquaintance with the mental process of imagination is of great value to the teacher. The leading facts connected with this process will be set forth in [Chapter XXVII].
PRECAUTIONS IN USE OF MATERIALS
In the use of objective and illustrative materials the following precautions are advisable:
1. Their use in the lesson should not be continued too long. It should be remembered that their office is illustrative, and the aim of the teacher should be to have the pupils think in the abstract as soon as possible. To make pupils constantly dependent on the concrete is to make their thinking weak.
2. The pupils must be mentally active while the concrete object or illustrative material is being used, and not merely gaze in a passive way upon the objects. It requires mental activity to grasp the abstract facts that the objects or illustrations typify. A tellurion will not teach the changes of the seasons; bundles of splints, notation; nor black-board examples, the law of agreement; unless these are brought under the child's mental apprehension. The sole purpose of such materials is, therefore, to start a flow of imagery or ideas which bear upon the presented problem.
3. The objects should not be so intrinsically interesting that they distract the attention from what they are intended to illustrate. It would be injudicious to use candies or other inherently attractive objects to illustrate number facts in primary arithmetic. The objects, not the number facts, would be of supreme interest. The teacher who used a heap of sand and some gunpowder to teach what a volcano is, found his pupils anxious for "fireworks" in subsequent geography classes. The science teacher may make his experiments so interesting that his students neglect to grasp what the experiments illustrate. The preacher who uses a large number of anecdotes to illustrate the points of his sermon, would be probably disappointed to know that the only part of his discourse remembered by the majority of his hearers was these very anecdotes. In his enthusiasm for objective teaching, the teacher may easily make the objects so attractive that the pupils fail altogether to grasp what they signify.
4. In the case of pictures, maps, and sketches, it is well to present those that are not too detailed. A map drawn on the black-board by the teacher is usually better for purposes of illustration than a printed wall map. The latter shows so many details that it is often difficult for the pupil to single out those required in the lesson. The black-board map, on the other hand, will emphasize just those details that are necessary. For the same reason the sketch is often better than the printed picture or photograph. Any one who can sketch rapidly and accurately has at his disposal a valuable means of communicating knowledge, and every teacher should strive to cultivate this power.
MODES OF PRESENTATION COMPARED
The relative clearness of different modes of presenting knowledge may be seen from the following: