Page:American Journal of Psychology Volume 21.djvu/535

Rh procedure. Our present terminology and analyses, he points out involve an unfortunate dualism, like the dualism of body and soul to which it harks back. We have been accustomed to think of the sensory stimulus as one thing, the central activity, standing for the idea, as another, and the motor discharge, standing for the act proper, as a third. But instead of viewing these elements as each a distinct entity, they should be viewed as "divisions of labor, functioning factors, within the single concrete whole, now designated the reflex arc." (p. 358.) A stimulus always breaks into a coördination and not into a sensation mass. Whenever we turn round upon ourselves what we find is a coördination, an act taking place. Within this act lie both sensation and movement as phases of it.

On the basis of this conception this much may be laid down, namely, that voluntary movement never starts de novo and never begins with a mere sensation mass; it always breaks in upon an existing coördination. But when consciousness plays a part in the formation of a new adjustment or rather the modification of an existing one, attention is directed to the sensation phase of the coördination because this phase represents the existing situation with reference to which the adjustment is made. When, now, one asks, precisely what elements of the sensation phase of coördination must attention be directed to, any of it, all of it, or only certain elements of it, the position of the image theory at once becomes arbitrary; for, to be consistent, it must hold that immediate sensations are not a sufficient basis upon which to make a volitional movement,—there must be present images of sensations experienced in involuntary and reflex activity. The objections here raised are that this position is first of all highly arbitrary, and secondly, as Thorndike has pointed out, puts volitional over against involuntary activity so as to make the former radically distinct from the latter. Moreover, whether we regard voluntary movement as an activity developed out of original reflexes, or whether we regard reflexes as the products of conscious impulses and volitional control the relation between them, in either case, is rendered arbitrary if we take the position that in voluntary action certain senses and ideational elements are the essentials while in other forms of activity any peripheral or central processes that bear a relation to the situation with reference to which the act is performed are sufficient.

At this point the theoretical exposition of "Consciousness and Movement," by Judd, based upon a variety of experimental studies by himself and his associates in the Yale Laboratory, is significant. Judd calls attention to the distribution of the sensory areas in the cortex. "The sensory centres," he says, "except the centre for touch, are distributed in the