[12] Loc. cit., p. 351-352.
It is obvious that motor expressions of shock or motor methods of adaptation or reaction are much older and far more prominent than psychic. But although a changed environment made the old types of defense obsolete, they still persist, "in a sthenic if somewhat now inco-ordinated way, and when they are called into action now they evoke a faint phosphorescence of the old primordial feeling."[13]
[13] Loc. cit., p. 197.
In brief it should be said that no matter how refined and how highly cultured we are, we still fear and react to emotions "in the same terms of the same old gross organs and functions as do the brutes."[14]
[14] Loc. cit., p. 197.
REGRESSION
As I have stated in a previous paper,[15] the pathogenesis of tics and allied conditions can best be appreciated by viewing the subject from an evolutionary standpoint. In our reactions and adaptations to the varying experiences with which we meet we respond by one or more of several methods of motor reaction. These motor expressions are of increasing complexity as we ascend the scale of evolution and development. One of the simplest kinds of adaptation is by simple, reflex muscular action, the response being anatomical and not physiological in its extent. Then come our simple physiological reactions. A more complex reaction is by those physiologically co-ordinated motor reactions or movements which go to comprise our pantomimic movements. This is seen most characteristically in our facial expressions, gestures, mimicry and dancing. Still higher up in the scale we find our conduct and feelings as exemplified in our speech. And finally, highest of all, we must place our conduct as shown in written or printed language. This is a brief outline of our evolutionary and developmental ascent and of the increasing complexity and refinement of our social conduct.
[15] Tics. Interstate Medical Journal, January and February, 1915.
In our motor adaptations we respond in one or more of these ways. When for some reason or another one outlet us denied us, we find avenues of expression through one or more of the other paths. Now, the manner and degree of our response is dependent on our stage in evolution and development, on the development of our senses, on our instincts, feelings and emotions, on our intellect and experiences. Unable to find expression by means of writing or speech, we instinctively fall back upon and seek expression by a less refined method, one earlier acquired and thus lower in the scale of evolution. This has a more or less general application throughout the scale of human (individual and social) conduct. It is an application of the universal law of adaptation to existing conditions in the best manner possible under the circumstances. We may thus lay down in a general sort of way a conception which I like to call the theory of psychophysical progression, fixation and regression along evolutionary and developmental lines. In the case of tics the regressive or devolutionary aspect comes in for special consideration. We may react mainly physically, or mainly psychically. But as a rule we react by both physical and psychic means, the manner and degree of our conduct being determined, as above mentioned, by our stage in evolution and development.
How does all this preliminary and general discussion apply to the problem of the tics? The relation seems to me to be most intimate and most important. The tics are methods of response or reaction to certain external irritations or ideas, this response being the manner of adaptation. The response may be mainly motor or mainly psychic, most frequently psychomotor. When the source of irritation and the cause for action is known, our conduct is more specific and is apt to be less diffuse, less inadequate, less indefinite. In our reactive adaptations, which, as explained above, are greatly dependent upon our psychophysical make-up or constitution, we protect ourselves consciously or more or less unconsciously against disagreeable, inimicable, unpleasant or irritating environmental factors, physical or psychical, by bringing into activity certain psychical or physical or psychophysical reactions or processes. The special defense reactions brought into the foreground are those which follow the line of least resistance, due to hereditary or environmental construction, or are those which were most intensely stimulated or irritated and the most biologically useful and adaptive at the particular moment or under the special circumstances. The young child's reactions are preponderately motor, or at any rate psychomotor and not purely psychic. When there are sources of irritation or bodily or mental discomfort, there is a more or less general bodily reaction, psychophysical in nature. When the irritation is definite and clearly recognized by the child, the local motor response is also apt to be definite. When, on the other hand, the irritation is but vaguely perceived and not clearly appreciated or localized, we find that the child may show a general diffuse reaction, or even, in some cases, a reaction limited to certain regions as determined by the reaction taking place along the line of least resistance. This is plainly seen in the conduct of the physically sick child. Every pediatrician will find ample proof in support of this statement in his observations of the defensive reactions of the ill child.