=Habit and Consciousness.=--While saying that such habitual action may be performed with facility in the absence of conscious direction, it must not be understood that conscious attention is necessarily entirely absent during the performance of an habitual act. In many of these acts, as for instance, lacing and tieing a shoe, signing one's name, etc., conscious effort usually gives the first impulse to perform the act. There may be cases, however, in which one finds himself engaged in some customary act without any seeming initial conscious suggestion. This would be noted, for instance, where a person starts for the customary clothes closet, perhaps to obtain something from a pocket, and suddenly finds himself hanging on a hook the coat he has unconsciously removed from his shoulders. Here the initial movement for removing the coat may have been suggested by the sight of the customary closet, or by the movement involved in opening the closet door, these impressions being closely co-ordinated through past experiences with those of removing the coat. When, also, a woman is sewing or kneading bread, although she seems to be able to give her attention fully to the conversation in which she may be engaged, yet no doubt a slight trace of conscious control is still exercised over the other movements. This is seen in the fact that, whenever the conversation becomes so absorbing that it takes a very strong hold on the attention, the habitual movements may cease without the person being at first aware that she has ceased working.
=Habit and Nervous Action.=--The general flow of the nervous energy during such processes as the above, in which there is an interchange between conscious and habitual control, may be illustrated by the following figures. In these figures the heavy lines indicate the process actually going on, while the broken lines indicate that although such nerve courses are established, they are not being brought into active operation in the particular case.
A. Sensory Stimulus B. Lower Sensory Centre C. Higher Sensory Centre
A' Higher Motor Centre B' Lower Motor Centre C' Motor Response]
The arrows in Figure 1 indicate the course of sensory stimulation and motor response during the first efforts to acquire skill in any movement. No connections are yet set up between lower centres and the acts are under conscious control.
