are highly volitional, as has been frequently the case in studies of reaction time, how is it possible to have a sensory type of reaction at all? Suppose, for example, the subject is reacting with his toe or his lips as in the case of Angell and Moore's study. In this case the image theory would demand that before the subject could make his reaction there must appear in consciousness some kind of image of the movement itself. Here, then, it would be misleading to speak of a sensory type of reaction for the reason that the image of the stimulus would have to be followed by an image of the movement either as felt, seen, or experienced in some other form, before the movement could be made. That the intervention of such an image does not necessarily take place, particularly after practice, is pretty well established by Ach and (by implication) by Downey and by experiments to be described later in this paper. This makes the concept of sensory and motor types of reaction correspond to what the names imply and to what has been commonly understood to be the distinction between them.
In interpreting his own theory James has said: "In the chapter on the Will we shall learn that movements themselves are results of images coming before the mind, images sometimes of feelings in the moving part, sometimes of the movements' effects on the eye and ear and sometimes (if the movement be originally reflex or instinctive) of its natural stimulus or exciting cause." (Vol. I, p. 445.) The literature reviewed and the arguments already set forth demand a modification of this position.
It is clear that much of the older literature bearing upon voluntary movement is not only general in character but to a degree at least a priori in its derivation, and hence, as Woodworth has pointed out, logical and schematic rather than strictly psychological in its treatment. The weakness of these older studies is therefore primarily methodological but a weakness which in turn brought errors of result and interpretation. Another methodological error that has crept into certain more recent studies of voluntary movement is that of studying thoroughly practiced movements, and from such study drawing inferences with reference to voluntary movement in general. 'To instruct a person verbally to make certain very familiar movements and then from the absence of supplementary imagery to draw the inference that imagery in general is not necessary for voluntary movement' (cf. Angell 's review of "The Cause of a Voluntary Movement." Jour. of Phil. Psy. and Sti. Meth., Vol. 3, pp. 641 f.), is not only an error of fact, as will be shown later in this discussion, but is primarily an error of procedure which leads directly to the error of fact.
