Thus we may classify acts as wholly involuntary or mechanical, as impulsive, and as distinctly voluntary or purposive. Or, we may arrange acts in a scale from those that have no conscious end, through those aimed directly at an immediate end, up to those done to accomplish an ulterior end which is imagined beforehand. The last class of fully voluntary acts belongs under the general head of manipulation, just as imagination does. We imagine some change to be produced in the existing situation and then proceed to put our imagination into effect; and this is a typical voluntary act.

We seldom, however, picture a complete act in imagination before executing it. Even so simple an act as closing the fist cannot be completely pictured beforehand; for if you try to imagine how the closed fist is going to feel and then close it, you will find that you left out of your image many details of the actual kinesthetic sensations. What we imagine and intend is some change in the situation, and we then proceed to execute that change and other changes incidentally.

Besides the simple reflexes, there is another sort of involuntary and mechanical action. Through practice and repetition, an act may become so habitual as to be done automatically, that is, without being imagined beforehand, and even without conscious impulse. The practised typist responds in this way to the words he is copying. We should notice, however, that this does not mean that the total behavior and state of mind of the typist is mechanical and devoid of impulse. The typist may write the letters [{526}] mechanically, and if expert may write even words in this way, but all the time he is consciously aiming to copy the passage. His attention and impulse have deserted the fully mastered details and attach themselves to the larger units. In the same way, in signing your name you have no conscious intention or impulse to write each successive letter; but you fully intend to sign your name.

Development of Voluntary Control

The child's actions are at first impulsive but not voluntary in the full sense, since obviously he cannot imagine and intend an act till he has had experience of that act, and he must usually have experienced doing the act himself before he can effectively imagine it. At least, this is true of the simpler movements; compound movements, made up of familiar elements, may be first observed in other persons and then voluntarily imitated. The child's process of acquiring voluntary control over a movement is illustrated by the story of how the baby learned to put his hand in his mouth. He first made this movement in the course of "aimless" throwing of his arms about, liked the sensation of the hand in the mouth, tried apparently to get it there again, and in the course of a few days was able to put it there at will. The child's "aimless" movements at the start were probably impulsive, but they were not directed towards any preconceived end. Then, having observed a desirable result of one movement, he worked towards that result by trial and error, till finally he had the necessary movement so closely linked to the thought of the result as to follow directly upon the thought.

Once brought under voluntary control, a movement becomes with further repetition habitual and mechanical, and no longer voluntary or even impulsive. Thus the voluntary [{527}] performance of an act intervenes between the native or instinctive doing of it and the later habitual doing of it. Blowing out a match affords another example of this course of events. A child can of course blow out, instinctively, when he has the natural stimulus for strong expiration, but he cannot at will blow at the lighted match. Being prompted and shown, he comes by degrees to be able to blow out the match; during the learning stage he has to try, and the act is voluntary; but with further practice it becomes involuntary, though it may still be executed as part of a larger voluntary act, such as preventing a burning match from setting fire to something on which it has fallen.

A complex act, or series of movements, may be voluntary as a whole, being directed towards some preconceived result, while the single movements that constitute the series are mechanical, their particular results no longer being thought of separately. This is well illustrated by the instances of typewriting, speaking, and signing the name, mentioned a moment ago. With practice, the interest in a performance goes more and more to the final result and deserts the elements of the act.

It is during the organization of reactions that they require attention and must be thought of before being executed. Organization goes on and on, a thoroughly organized reaction being later combined with others into a still bigger act. New demands constantly made upon the individual prevent him, however well organized, from ever reaching the condition of a wholly automatic machine. Will, in the sense of action aimed at the accomplishment of foreseen results, stays with him to the end.

Ideomotor Action

Involuntary movement is not always "sensorimotor", which means directly aroused by a sensory stimulus; oftener [{528}] it is "ideomotor", or directly aroused by an idea or thought. It may be so aroused and still be involuntary. We think of a certain result and our muscles produce this result, though we did not really mean to do this act ourselves. The thought arouses the movement because it has previously been linked with the movement. A thought which has previously served as the stimulus to an act will tend to have this effect again, unless inhibited by some contrary stimulus. There is no need of a definite consent to the act, provided there is nothing present to inhibit it.