The different psychic operations which we have so far considered - perception, association of ideas, affective phenomena - find their outward expression in the reactions. Like association of ideas, reactions may be of two kinds: voluntary and automatic.

Between a voluntary act accomplished in full self-possession and a purely automatic act there are all intermediate gradations; we pass from one to the other by gradual insensible transition. The participation of the conscious will diminishes as that of the automatism becomes more prominent, or inversely.

We have seen that in normal ideation voluntary and conscious associations tend to inhibit automatic associations. Similarly the conscious will tends to inhibit automatic reactions.

We shall study: (1) aboulia, or paralysis of voluntary reactions; and (2) automatic reactions.

Aboulia

Complete paralysis of the will brings about, depending upon the character of the case, either stupor or absolute automatism. When less pronounced it is manifested clinically by a general sense of fatigue and discouragement, by slowness and unsteadiness of the movements, and by the painful effort that is necessary for the accomplishment of all spontaneous or commanded acts. The voluntary apparatus then resembles a rusty mechanism which works only with difficulty.

Like sluggishness of association, which in most cases accompanies it, aboulia is a manifestation of psychic paralysis.

Automatic Reactions

These may be paralyzed in the same degree as voluntary reactions and give place to the absolute inertia of stupor; or, on the contrary, they may become exaggerated by reason of weakening of the conscious will.

We distinguish: (A) positive automatic reactions; and (B) negative automatic reactions.

(A) Positive automatic reactions are expressed clinically by two phenomena: suggestibility and impulsiveness.

By suggestibility is understood a state in which the reactions are compelled by external impressions. Its most perfect expression is catalepsy, in which the limbs assume ,and retain the attitudes in which they are placed by the examiner. This phenomenon has been termed waxy flexibility (flexibilitas cerea).

Many patients appear to have lost all individual will and are reduced to mere automatons. Some repeat exactly the words (echolalia) or the gestures (echopraxia) of the persons around them. Others exhibit no spontaneous activity, but are able to execute without hesitation any command. Such is the case with hypnotized subjects, certain catatonics, etc. Sometimes it suffices to start them moving, when they will continue and accomplish a series of acts to which they are accustomed.

Suggestibility is the dominant note of the character of certain persons, mostly credulous and weak-minded, whose thoughts are governed by external impressions, whose will is nil, and who yield to the domination of the most diverse influences, good or bad. Many criminals belong to this class.

Impulsive reactions or impulses are to be divided into three groups: (a) impulses of passion; (6) simple impulses; (c) phenomena of stereotypy.

(a) Impulses of passion always depend upon abnormal irritability. They are determined by provocation that is often insignificant and are accomplished independently of any mental reflection. They are met with in a great many patients: constitutional psychopaths, epileptics, maniacs, etc. A maniac feels his neighbor give him a slight push; he immediately strikes him without reflecting that the latter had no malevolent intention, that he was perhaps even unconscious of having touched him, etc. This is an impulse of passion.

(b) Simple impulses, purely automatic, appear without any emotional shock and without a shadow of provocation. One patient suddenly threw into the fire the gloves, hat, and handkerchief of her daughter who came to visit her at the sanatorium. Afterwards during a moment of remission she remembered perfectly the act and the circumstances under which it was accomplished, but was not able to furnish any explanation for it.

The impulse may be conscious. A patient is suddenly seized with a strong desire to steal some object from a show-window, the possession of which could be neither useful nor pleasant to him; he does not yield to this impulse, which he recognizes as pathological. This is a conscious impulse. This phenomenon is closely allied to imperative idea, of which it is but an accentuation.

(c) Stereotypy consists in a morbid tendency to retain the same attitude, or to repeat the same movement or the same words. Hence the three kinds of stereotypy:

Stereotypy of attitudes;

Stereotypy of movements;

Stereotypy of language: verbigeration.

Certain patients remain for hours at a time in most uncomfortable attitudes; others will walk a long distance, taking alternately three steps forward and two backward; still others will repeat indefinitely the same phrase or the same verse.

(B) Negative Automatism

This forms the basis of negativism and consists in the annulment of a voluntary normal reaction by a pathological antagonistic tendency.

The patient is requested to give his hand; the voluntary reaction which tends to appear and which would result in compliance with the request, is arrested, suppressed by automatic antagonism. This disorder of the will has been designated by Kraepelin, who has made an admirable study of it, by the term Sperrung, a word which, literally translated into English, means blocking. A more significant term perhaps would be psychic interference. The two antagonistic tendencies neutralize each other like interfering sound-waves in physics.

On a superficial examination negativism may resemble aboulia. These are, however, two very different phenomena. While the latter, purely passive, is the result of persistent paralysis against which the patient struggles with more or less success, the former, an active phenomenon, depends not upon paralysis but upon a perversion of the will. Negativism is often manifested only in certain kinds of reactions. One patient who walks about without any effort does not open his mouth. Another who dresses himself, eats unassisted, and even works, remains in complete mutism, making no response in spite of all perseverance on the part of the questioner.

In a more marked degree negative automatism results not only in the arrest of normal reactions, but also in the production of contrary reactions.

Thus if one attempts to flex the patient's head he extends it, and vice versa. If he is requested to open his half-shut eyes he closes them, and if the examiner attempts to force them open, his orbicularis muscle contracts in a veritable spasm. Wernicke observed that while flexibilitas cerea chiefly shows itself in the limbs, negativism mostly affects the muscle groups of the head and neck.