This incomplete command of the voice is frequently observed, even among singers of very high standing. At first sight the condition here described seems to disprove the statement that the voice normally obeys the ear. But there is no real contradiction of the psychological law of vocal command in the case of a stiff-throated singer. For one thing, whatever degree of command the singer possesses is obtained in accordance with the law of guidance by the ear. Moreover, the failure to secure perfect response is due solely to the interference with the normal workings of the voice, occasioned by the state of throat stiffness. Far from this form of muscular contraction being a contradiction of psychological principles, it will be found on examination to be in perfect accord with well-established laws of physiological psychology.
It is hardly to be supposed that the singer consciously and voluntarily contracts the muscles of the entire vocal mechanism and so deliberately brings about the stiffening of the throat. True, this can readily be done. We can at will sing throaty and nasal tones. But this form of voluntary throat tension is not, properly speaking, an incorrect vocal action. So long as the vocal organs respond to the demands of the ear, the vocal action is correct. Only when the voice refuses to obey can the action be described as incorrect.
A satisfactory definition of the various modes of vocal action can now be given. The correct vocal action is the natural operation of the vocal organs; the voice normally obeys the commands of the ear. An incorrect vocal action occurs when the throat is stiffened by the involuntary contraction of the muscles of the vocal mechanism.
This definition of the vocal action does not solve the problem of tone-production. It is still to be determined how the involuntary contraction of the throat muscles is caused.
[CHAPTER II]
THE CAUSES OF THROAT STIFFNESS AND OF INCORRECT VOCAL ACTION
Involuntary contractions of the voluntary muscles can occur only as reflex actions. If the muscles of the vocal organs are subject to involuntary contractions, the causes of these contractions must be sought through an investigation of the subject of reflex actions.
Reflex actions are of several kinds; of these the simplest type, and the one most easily studied, is the muscular contraction due to the excitation of the sensory nerve endings located in the skin. Thus when the sole of the foot of a sleeping person is tickled, the leg is at first drawn up and then violently kicked out. An exhaustive discussion of the physiological and psychological features of reflex action is not called for here; a sufficient understanding of the subject may safely be assumed to be possessed by the reader.
Involuntary muscular contractions often occur as reflex actions without any direct or tactual irritation of the sensory nerve endings. Several examples of this form of reflex action are now to be considered. These actions will be seen to be matters of such common experience as to call for no special proof. They are the following: