Why are musical tones in a certain order and rhythm pleasurable? asked Darwin in The Descent of Man, and he concluded that the question was insoluble. We see that, in reality, whatever the ultimate answer may be, the immediate reason is quite simple. Pleasure is a condition of slight and diffused stimulation, in which the heart and breathing are faintly excited, the neuro-muscular system receives additional tone, the viscera gently stirred, the skin activity increased; and certain combinations of musical notes and intervals act as a physiological stimulus in producing these effects.[[107]]
Among animals of all kinds, from insects upward, this physiological action appears to exist, for among nearly all of them certain sounds are agreeable and attractive, and other sounds indifferent and disagreeable. It appears that insects of quite different genera show much appreciation of the song of the Cicada.[[108]] Birds show intense interest in the singing of good performers even of other species. Experiments among a variety of animals in the Zoölogical Gardens with performances on various instruments showed that with the exception of seals none were indifferent, and all felt a discord as offensive. Many animals showed marked likes and dislikes; thus, a tiger, who was obviously soothed by the violin, was infuriated by the piccolo; the violin and the flute were preferred by most animals.[[109]]
Most persons have probably had occasion to observe the susceptibility of dogs to music. It may here suffice to give one personal observation. A dog (of mixed breed, partly collie), very well known to me, on hearing a nocturne of Chopin, whined and howled, especially at the more pathetic passages, once or twice catching and drawing out the actual note played; he panted, walked about anxiously, and now and then placed his head on the player's lap. When the player proceeded to a more cheerful piece by Grieg, the dog at once became indifferent, sat down, yawned, and scratched himself; but as soon as the player returned once more to the nocturne the dog at once repeated his accompaniment.
There can be no doubt that among a very large number of animals of most various classes, more especially among insects and birds, the attraction of music is supported and developed on the basis of sexual attraction, the musical notes emitted serving as a sexual lure to the other sex. The evidence on this point was carefully investigated by Darwin on a very wide basis.[[110]] It has been questioned, some writers preferring to adopt the view of Herbert Spencer,[[111]] that the singing of birds is due to "overflow of energy," the relation between courtship and singing being merely "a relation of concomitance." This view is no longer tenable; whatever the precise origin of the musical notes of animals may be,—and it is not necessary to suppose that sexual attraction had a large part in their first rudimentary beginnings,—there can now be little doubt that musical sounds, and, among birds, singing, play a very large part indeed in bringing the male and the female together.[[112]] Usually, it would appear, it is the performance of the male that attracts the female; it is only among very simple and primitive musicians, like some insects, that the female thus attracts the male.[[113]] The fact that it is nearly always one sex only that is thus musically gifted should alone have sufficed to throw suspicion on any but a sexual solution of this problem of animal song.
It is, however, an exceedingly remarkable fact that, although among insects and lower vertebrates the sexual influence of music is so large, and although among mammals and predominantly in man the emotional and æsthetic influence of music is so great, yet neither in man nor any of the higher mammals has music been found to exert a predominant sexual influence, or even in most cases any influence at all. Darwin, while calling attention to the fact that the males of most species of mammals use their vocal powers chiefly, and sometimes exclusively, during the breeding-season, adds that "it is a surprising fact that we have not as yet any good evidence that these organs are used by male mammals to charm the female."[[114]] From a very different standpoint, Féré, in studying the pathology of the human sexual instinct in the light of a very full knowledge of the available evidence, states that he knows of no detailed observations showing the existence of any morbid sexual perversions based on the sense of hearing, either in reference to the human voice or to instrumental music.[[115]]
When, however, we consider that not only in the animals most nearly related to man, but in man himself, the larynx and the voice undergo a marked sexual differentiation at puberty, it is difficult not to believe that this change has an influence on sexual selection and sexual psychology. At puberty there is a slight hyperæmia of the larynx, accompanied by rapid development alike of the larynx itself and of the vocal cords, which become larger and thicker, while there is an associated change in the voice, which deepens. All these changes are very slight in girls, but very pronounced in boys, whose voices are said to "break" and then become lower by at least an octave. The feminine larynx at puberty only increases in the proportion of 5 to 7, but the masculine larynx in the proportion of 5 to 10. The direct dependence of this change on the general sexual development is shown not merely by its occurrence at puberty, but by the fact that in eunuchs in whom the testicles have been removed before puberty the voice retains its childlike qualities.[[116]]
As a matter of fact, I believe that we may attach a considerable degree of importance to the voice and to music generally as a method of sexual appeal. On this point I agree with Moll, who remarks that "the sense of hearing here plays a considerable part, and the stimulation received through the ears is much larger than is usually believed."[[117]] I am not, however, inclined to think that this influence is considerable in its action on men, although Mantegazza remarks, doubtless with a certain truth, that "some women's voices cannot be heard with impunity." It is true that the ancients deprecated the sexual or at all events the effeminating influence of some kinds of music, but they seem to have regarded it as sedative rather than stimulating; the kind of music they approved of as martial and stimulating was the kind most likely to have sexual effects in predisposed persons.
The Chinese and the Greeks have more especially insisted on the ethical qualities of music and on its moralizing and demoralizing effects. Some three thousand years ago, it is stated, a Chinese emperor, believing that only they who understood music are capable of governing, distributed administrative functions in accordance with this belief. He acted entirely in accordance with Chinese morality, the texts of Confucianism (see translations in the "Sacred Books of the East Series") show clearly that music and ceremony (or social ritual in a wide sense) are regarded as the two main guiding influences of life—music as the internal guide, ceremony as the external guide, the former being looked upon as the more important.
Among the Greeks Menander said that to many people music is a powerful stimulant to love. Plato, in the third book of the Republic, discusses what kinds of music should be encouraged in his ideal state. He does not clearly state that music is ever a sexual stimulant, but he appears to associate plaintive music (mixed Lydian and Hypolydian) with drunkenness, effeminacy, and idleness and considers that such music is "useless even to women that are to be virtuously given, not to say to men." He only admits two kinds of music: one violent and suited to war, the other tranquil and suited to prayer or to persuasion. He sets out the ethical qualities of music with a thoroughness which almost approaches the great Chinese philosopher: "On these accounts we attach such importance to a musical education, because rhythm and harmony sink most deeply into the recesses of the soul, and take most powerful hold of it, bringing gracefulness in their train, and making a man graceful if he be rightly nurtured, ... leading him to commend beautiful objects, and gladly receive them into his soul, and feed upon them, and grow to be noble and good." Plato is, however, by no means so consistent and thorough as the Chinese moralist, for having thus asserted that it is the influence of music which molds the soul into virtue, he proceeds to destroy his position with the statement that "we shall never become truly musical until we know the essential forms of temperance and courage and liberality and munificence," thus moving in a circle. It must be added that the Greek conception of music was very comprehensive and included poetry.
Aristotle took a wider view of music than Plato and admitted a greater variety of uses for it. He was less anxious to exclude those uses which were not strictly ethical. He disapproved, indeed, of the Phrygian harmony as the expression of Bacchic excitement. He accepts, however, the function of music as a κάθαρσις of emotion, a notion which is said to have originated with the Pythagoreans. (For a discussion of Aristotle's views on music, see W. L. Newman, The Politics of Aristotle, vol. i, pp. 359-369.)