Page:Popular Science Monthly Volume 50.djvu/70

58 on the part of the child. They do not enter into consciousness during their performance, but are often remembered after they have been performed. The images left in the memory after these movements have been executed are a very great factor in the development of the will, for the voluntary movements which develop later are based upon these impulsive and reflex movements.

Beginning somewhat later than the impulsive and reflex movements are the instinctive movements. We may say that the instinctive movements are an advance on the reflex movements, as they are more complex, they enter somewhat into consciousness, and there is a purpose in them, though the child does not know at the time he performs the movement the end that is to be attained.

The first movements of the child are impulsive and reflex, and no self-consciousness accompanies them. Yet every movement, whether impulsive or reflex, leaves some slight trace in the developing brain, and when the movement is hit upon again, and then again, and still many times again, this trace strengthens and associates itself with the particular movement, and there arises in the dawning consciousness an idea, the elements of which are very largely motor; and so numerous motor ideas arise. The three classes of movements which I have described are involuntary, and out of all these various involuntary movements spring up motor ideas. The pleasure or pain necessarily accompanying these gives rise in consciousness to desire to repeat these movements or to inhibit or stop them. Deliberative or voluntary movements are not possible without motor ideas. Through these motor ideas the child comes gradually to represent to himself some end to be attained or avoided. To say, then, that the will develops first through the motor side is warrantable.

I have indicated how motor ideas are involved at the start in the psychic or mental life, and how it is "only after a motion has taken place that the child acquires any knowledge of its own motor act." We must not, however, lose sight of the fact that there is blended or associated with the motor acts sensations coming from the eye and the ear and from other sensory avenues. Involved in all these motor acts is an extensive part of the cortex of the brain called the motor centers, because all muscular movements are controlled from these centers. Not only do these motor centers play a great part in the development of the psychic life and the rise of the will, but all other parts of the brain come to be developed in communication with them. Prof. Baldwin has expressed the idea that it is the motor which holds the sensory elements together, and Dr. Crichton Browne has said that an analysis of our ideas reveals to us that we have few if any of purely sensory characteristics. All our ideas, then, have