Since these movements are progressively acquired, the child’s first efforts can hardly be said to be voluntary. Many that are instinctive and automatic must be repeated over and over before voluntary ones come, for will implies an image which is a memory picture of the movement to be made. Preyer thinks that no intentional movements are made before the end of the first quarter.[156] Vierordt, indeed, says that their development is gradually progressive. “All indications point to the arm as first becoming obedient to volition, and the sucking movements, too, seem early to lose their reflex character. Then follow intentional movements of the head and neck and some groups of face muscles, and finally those of the lower limbs, which as late as the sixth month still move in the most haphazard manner.”[157] Playful experiment then promotes this acquisition of control over the bodily movements by the will, and strengthens and renders it permanent after it has been acquired. Playful movements naturally fall into two great subdivisions, namely, those belonging to the organs as such and those directed toward other objects in connection with such organs—a distinction already familiar to us in our study of the production of noises and tones. We will now consider the first of these divisions, the most important phenomenon of which is locomotion. A. PLAYFUL MOVEMENT OF THE BODILY ORGANS In other connections we have touched upon many movement plays, such as voice practice and the production of sounds by means of various bodily organs, experimentation with tactile stimuli, and watching moving objects. This sort of exercise often combines motor with sensor play, as has been frequently pointed out. Therefore, to avoid repetition, I will in this section, after a few preliminary remarks suggested by such bearings of the subject as I conceive to be essential, proceed at once to consider the most important and obvious of all movement-plays—namely, those connected with change of place. In voice practice experiments with the larynx, tongue, lips, and breathing muscles are involved. When children whisper, for example, their enjoyment must be due as much to the lip movements as to the slight sounds produced. The fact that the blind deaf-mute Laura Bridgman[158] playfully indulged in the production of various sounds seems to confirm this, and the principle is applicable too to other noises. The child who claps his hands, splashes in the water, bangs on the table with his fist, or puffs out his cheeks to blow a horn; the grown man who shuffles his feet, drums on the table or window pane, the noisy dancer, and even the piano or violin player who indulges in movements now loud, now soft, now slow, now quick—all derive a considerable part of their pleasure in the sport from the motor discharge which is involved.