It is a very simple but inviolable rule that where there is an obvious straining to produce an effect by the use of any training aid, then the effect of the training aid is lost and the speaker is proportionately enfeebled. A famous World War II commander said of all operations: "It is the chaps, not the charts, that get the job done." What needs to be kept in mind is the psychological object in their use. The scientists tell us, and we can partly take their word for it, that people learn about 75 percent of what they know through their sight, 13 percent through their hearing, and 12 percent through their other senses. But this is a relative and qualitative, rather than an absolute, truth. It has to be so. Otherwise, book study, which employs sight exclusively, would be the only efficient method of teaching, and oral instruction, which depends primarily on sound impact, would be a wasteful process. The more fundamental truth is that when oral instruction is properly done, the mind becomes peculiarly receptive because it is being bombarded by both sight and sound impressions. Nor is this small miracle wrought primarily by what we call training aids. The thoughts and ideas which remain most vivid in the memory get their adhesive power because some particular person said them in a graphic way in a pregnant moment. Our working thoughts are more often the product of an association with some other individual than not. We remember words largely because we remember an occasion. We believe in ideas because first we were impressed by the source whence they came. The total impression of a speaker--his sincerity, his knowledge, his enthusiasm, his mien, and his gestures--is what carries conviction and puts an indelible imprint on the memory. Man not only thinks, but he moves, and he is impressed most of all by animate objects. Vigorous words mean little or nothing to him when they issue from a lack-luster personality. Artificiality is one of the more serious faults, and it is unfortunately the case that though an instructor may be solid to the core, he will seem out of his element, unless he is careful to avoid stilted words and vague or catch-all phrases and connectives. Strength in discourse comes of simplicity. But it has become almost an American disease of late that we painfully avoid saying it straight. "We made contact, and upon testing my reaction to him, found it distinctly adverse" is substituted for "I met him and didn't like him." But what is equally painful is to hear public remarks interlarded with such phrases as "It would seem," "As I was saying," "And so, in closing," "Permit me to call your attention to the fact" and "Let us reflect briefly"--which is often the prelude to a 2-hour harangue.