Page:American Journal of Psychology Volume 21.djvu/530

518 (2) It is not always true that "the adequacy or inadequacy of images is a point of importance in judging how much of a real causal function the image has in the production of movement." (p. 362.) Many things come in to modify this "importance" of the adequacy or inadequacy. Reflexes, instincts, habits and "psycho-motor" tendencies all come in to supplement any lack that may exist on the part of the initial image. And, what is still more to the point, the immediately inflowing sensations, once a movement is started, are of incalculable service in the further control of it. Woodworth himself has pointed out that the coördinations of a movement are unconscious processes. The details, therefore, of a movement need not be included in the image in order that it be adequate.

(3) This idea is not a psychological concept. It is rather a logical, a priori idea, and as such practically the same argument may be urged against it that Woodworth presents in opposition to the image theory, namely, that it is too "schematic." As a sort of logical necessity it is apparently assumed that to be adequate the image must contain what will be contained in the forthcoming movement, and then, when introspection reveals that the image does not contain qualitatively and quantitatively what the movement sensations reveal, it is therefore declared "inadequate."

Woodworth refers also to his own attempt to learn to move the great toe in isolation from the others. "The establishment of complete voluntary control is a very gradual process." (p. 36.) He finds, too, with Bair, that the first success comes by accident. Gain in control is then made by directing attention to the member itself. In this, too, he agrees essentially with Bair who found that the final stage in getting control of a muscle consists, as has been stated, in dissociating the sensation of the movement of the muscles in question from the sensations derived from other and already controlled muscles. But while the kinæsthetic image, and in fact imagery of every sort, is entirely unnecessary, Woodworth holds, that kinæsthetic sensations from a member are indispensable, maintaining that "sensations are indeed always present, as contributing factors in determining the act. They represent the existing situation with reference to which the act is performed, and the act is determined by the existing situation as well as by the intention." (p. 383.) This position will be referred to again in the discussion of the relation of sensation to movement.

Thorndike calls attention to five facts, which in his judgment argue against the kinæsthetic theory.

(1) The same imagery will frequently be found employed