The nearest approach from the experimental side to the study of the effect of training in actual industrial tasks may be found in certain laboratory investigations which refer to the learning of telegraphing, typewriting, and so on. For instance, we have a careful study[20] of the progress made in learning telegraphy, both as to the transmitting of the telegrams by the key movement and the receiving of the telegrams by the ear. It was found that the rapidity of transmitting increases more rapidly and more uniformly than the rapidity of receiving. But while the curve of the latter rises more slowly and more irregularly, it finally reaches the greater height. The ability in transmitting, represented by a graphic record, shows an ascent which corresponds to the typical, steady curve of training. In the receiving curve, on the other hand, we find not far from the beginning a characteristic period during which no progress whatever can be noticed, and this is also repeated at a later stage. The psychological analysis shows that the increase of ability in the receiving of telegrams depends upon the development of a complex system of psychophysical habits. The periods in which the curve does not ascend represent stages of training in which the elementary habits are almost completely formed, but have not become sufficiently automatic. The attention is therefore not yet ready to start habits of a higher order. The lowest correlation refers to the single letters, after that to the syllables and words. As soon as the apprentice has reached this point, he stops, because he must learn to master more and more new words until his telegraphic vocabulary is large enough to make it possible for him to turn his consciousness to whole groups of words at once. Only when this new habit has been made automatic by a training of several months can he advance to a level at which whole groups of words are perceived as telegraphic units. A time follows in which this mastery of whole phrases advances rapidly, until a new period of rest comes, from which, only after years and often quite suddenly, a last new ascent can be noticed. Instead of concentrating the attention with conscious strain on single phrases, the operator progresses to a perfect liberty in which whole sentences are understood automatically.