CHAPTER IX.
THE EXTERNAL CONDITIONS OF EMOTION
Empiric period—Pre-Darwinian period of scientific research—Examination of Darwin’s three principles—Wundt and his explanatory formulas: Innervation directly modified, Association of analogous sensations, Relations of motion with sensory representations.
The movements of the eyes, mouth, face, the upper and lower limbs and trunk, and the modifications of the voice constitute the external expression of emotion which is principally reducible to muscular action. For the last half-century this subject has been studied in works so well known that it behoves us to be very brief. I shall confine myself to indicating the actual state of the question.
For some thousands of years this question remained in the stage of pure empiricism, or of so-called scientific speculations which had scarcely a better reputation than alchemy, astrology, or chiromancy. J. Müller, in the name of physiology, declared the expression of the emotions completely inexplicable. However, the researches were already beginning which were to prove him mistaken—those of Lavater with his rare talent of personal observation, and those of Charles Bell by a more objective method. After this, Duchenne, of Boulogne, went still further, substituting experiment for mere observation. It is well known that, in the case of an old man suffering from facial anæsthesia, he caused the contraction of an isolated muscle, by the aid of electricity, and thus produced certain modes of expression in the countenance. He concluded from this that the contraction of a single muscle often suffices to express a passion; and that every emotion has, so to speak, its accurate, precise, and unique note, produced by a unique local modification. Thus, the frontal is for him the muscle of attention, the upper orbicular of the lips the muscle of reflection, the pyramidal (inter-superciliary) expresses threats; the great zygomatic, laughter; the lesser zygomatic, weeping; the triangular muscle of the lips, disdain, etc. In spite of the somewhat artificial nature of the experiments, and the too sweeping character of the conclusions, this was a great step in advance.[[85]]
At last appeared Darwin’s epoch-making work. Supported by the results of a long series of experiments on adults, children, lunatics, animals, members of the different human races, Darwin was the first to put, and to attempt to answer, the fundamental and only question—Why and how is such and such an emotion connected with such and such a movement and not with another? He stated the problem under its scientific form.[[86]]
In Darwin’s works we find two elements: a detailed and complete description of each individual emotion or affective state—by which we shall profit later on—and the exposition of the general laws of expression, as reduced to three well-known principles. What remains of these three principles after the criticism to which they have been subjected? This is the only point we have, for the moment, to examine.
1. The principle of the association of serviceable habits remains the most firmly established. It consists in admitting that movements which are of service in satisfying a desire, or getting rid of a disagreeable sensation, become habitual, and continue to take place, even when their utility becomes nil, or at any rate doubtful. In other words, there are attitudes, gestures, movements, which can be directly explained, because they are nothing but emotions actualised, objectivised, or embodied, such as the movements of contact in tenderness, of aggression in anger, of erection and swelling in pride. But there are others, of which the explanation is less direct and obvious. How are the contraction of the eyebrows in perplexity, tears in sorrow, the showing of the teeth in anger, to be explained as serviceable to us? According to Darwin, these acts, formerly serviceable, have continued to exist as survivals. Here Darwin’s successors have rightly reproached him with not being enough of a psychologist, and have found a better explanation: the important fact is not the survival of serviceable movements, but the transference of a primitive mode of expression to an analogous emotion.
2. The principle of antithesis has been definitively abandoned; it is purely hypothetical, and explains nothing. According to Darwin, there is a primitive and general tendency to associate with feelings the contrary gestures to those expressing the opposite feeling. Léon Dumont has subjected this assertion to a very close and cogent criticism. Taking, one by one, the facts quoted by Darwin, which, besides, are not very numerous, he has shown that they may be quite otherwise explained.[[87]]
3. The principle of the direct action of the nervous system cannot be placed in line with the other two, because it far surpasses them in generality, and, in relation to it, they are subordinate and not co-ordinate. Before Darwin, Spencer (Principles of Psychology, ii. §§ 495, 502) had stated an analogous principle, to which he reduced the expression of the emotions. He calls it the Law of Nervous Discharge. It may show itself in two forms—the diffused and the restricted. The former depends on the quantity or intensity of the emotion, and serves as its measure. It follows, in its propagation, an invariable course: it affects the muscles in an inverse ratio to their mass and to the weight of the parts they have to move. In man, it acts first on the delicate muscles of the voice and the small facial muscles; then it invades, in succession, the arms, the legs, the trunk. The movements of the tail in dogs and cats, of the ear in horses, and many analogous ones in other animals, are illustrations of this law. The restricted discharge depends on the quality or the nature of the emotion; it is due “to the relations established in the course of evolution between particular feelings and particular sets of muscles habitually brought into play for the satisfaction of them.”[[88]] This scarcely seems to me to differ from Darwin’s principle of “useful habits.”
The Expression of the Emotions gave rise to other publications of the same kind, those of Piderit, Mantegazza, and Warner, who, in his Physical Expression (1885), has attempted a purely objective, and consequently extra-psychological study of the subject. But among all the attempts to trace back expression to its fundamental principles, and find a substitute for Darwin’s (already greatly shaken) theory, that of Wundt seems to me the best.[[89]] Like his predecessor, he admits three principles (though different from Darwin’s) which can act simultaneously and concur in the production of an isolated movement.