VISUAL INSTRUCTION is commonly considered as synonymous with teaching through the use of pictorial representations. In a wider sense it includes all instruction by which the material world reaches the mind through the sense of sight. The process is by no means a newly devised one. The human race has at all times ctepended upon the eye more largely than upon any other organ of sense for learning about material objects.
Photography has been the chief factor in the fuller use now being made of the visual method. By it even the most remote objects of every variety may be represented with a large degree of accuracy, and pictures of them may easily be placed before any observer. The expense involved is relatively very small. Photo graphic processes of producing plates from which excellent pictures are quickly made in enormous quantities on a printing press have made pictorial expression so common that it no longer attracts special attention. Schools, pub lishing houses and business concerns of all kinds have been quick to recovnize the effect iveness of the visual presentation of ideas and are making very large use of this form of ex pression. Man's first means of .communicating his ideas to others was spoken language. But he soon had occasion to make a record of his notions for the benefit of those at a distance or of a later time, and so invented symbols. These consisted of rude drawings and of char acters known as the alphabet. The early pic tographs expressed only a few simple ideas. Words formed from the alphabet do not directly suggest ideas. They come to have con tent only through much study and long farnili arity with them. To the spoken and the writ ten word must be added the picture fortn of ex pression. In considering the value of visual instruction it is important to recognize the fact that pictures serve not merely to make a pleas ing appeal to the eye, but have actually come to be a universally used mode of representing the physical world to the mind. Appreciating this fact, the problem is to determine the mental laws according to which the learner is af fected by them and the special fields of useful ness of visual presentation. That the true place
of pictures as a means of expressing ideas may be understood and used most effectively there needs to be a clear appreciation of the relative value of language and pictures in conveying ideas. An analysis of the whole body of ideas to which man has occasion to give expression must lead to the conclusion that pictures are best calculated to represent material objects. In other words they present to the mind facts to be perceived. Higher ideals and abstract relations must for the most part continue to be expressed through the mecfium of language.
All notions of the objective world are got ten through the senses, chiefly sight. The pri mary function of the mind by which the in dividual has experience with material things is called perception. The powers of judg ment, imagination and reasoning are absolutely dependent upon perception. They will work true only as perception has been clear, exact and vivid. Obviously one's first dealing with an objective field of study should be through observation. Children need to begin their studies through visual aids. More niature minds are dependent upon a visual presentation whenever they enter upon a new field of study that has to do with objective realities.
The perceptive facts that may be acquired through the medium of the eye are form, size, position, which inhere in every object, and some times color and sometimes motion. Pictures do not directly convey any other notion. Where the mind seems to see more than these eletnents, it is only by inference made possible through ex perience. The quantitative element is an im portant factor in visualization. Understand ing how large an object is requires a known standard of measure. There must be compari son, doubtless involving the function of judg ment. One's practical interest in the position of an object or part of an object usually hes in knowing its place in relation to something else already known. Form is dependent upon relative position of parts. The clearness and fullness with which the mind grasps such factors determine the accuracy and vividness of the visualization.