The primary function of mentality, as we have throughout assumed, is as stimulant to activities advantageous to the individual under the conditions of its existence; hence all these activities are in a broad sense expressions of mental state, they are the outflow of psychoses and are indicative of them. In particular, feeling is specially and directly related to motor values, which thus become to the self-observant or to others observant an index or expression of the feeling. Thus, I see a deer fleeing from a wolf, and I infer that this is an expression of fear. Hence we may rightly say that in a large sense all action is expression, for all such action rises in feeling; in other words, from one point of view expression equals action. Not only may exterior bodily phenomena betray the feeling which is their inciting cause, but to a vivisectionist, for example, interior phenomena, cerebral and other, may be noted as indicating a feeling origin. Excluding, of course, so-called reflex action, which is really reflex motion, action and expression are but different points of view of the same thing: what we term an action when we dwell upon the motor side, we term an expression when we dwell on the mental prius and stimulus which is revealed.

Now as the evolution of mind progresses actions no longer serviceable may survive in connection with given feelings, remain indicative of them; thus the strong beating 346of the heart in fear and the scowl in anger. Such survival actions which occur in connection with all kinds of feelings, and especially with those which are pre-human in their origin, are with particular emphasis styled expressions. The scowl in anger is considered as expression rather than the actual blow struck, which is equally the result and indication of anger.[F]

F. Wundt says that when in emotion we look “sour” we think we are actually tasting the sour, and so make the repulsing action, “sour” look. (Lectures on Psychology, p. 283.) I think it more probable that the “sour” look is the survival expression of such an emotion as disappointment. It is likely that the genesis of disappointment was in tasting the sour for the supposedly sweet, e.g., lemon for orange, and the “sour” look has remained as expression of disappointment long since its utility ceased. The genesis and early growth of most emotions is in connection with certain sense experiences and their related actions, and these actions tend to remain as “expressions” long after their real quality as actions has disappeared. Hence it is by survival, and not because he thinks himself tasting something sour, that a man looks “soured” by disappointment when I fail to give him money as promised. So also black is gloomy because we are diurnal, and our ancestors were diurnal. If nocturnal, black would seem joyous, white gloomy. (Cf. Wundt, ibid., p. 375.)

Expression is then primarily all action connected with all consciousness, secondarily, it is useless action continued by force of habit and transmitted to descendants. But still many expressions are more than mere actions or their survivals. To be sure, Darwin and many Darwinists maintain that the expressions do not arise or exist for their own value as such, but they are entirely incidental. Expression is not the function of the so-called expressions, but they are entirely functional survivals. While, however, we must admit that many expressions have arisen and been preserved in this manner, yet I think it is altogether hasty to deny the function and value of expression per se. Expression has existed as a function from very early phases of life, and it underlies all bisexuality and sociality which have been such important 347elements in evolution. Organic sound-producing structures, whose sole utility from the very first is for attracting attention, early appear, and further voice seems to have its origin in the demand for love-call and call to young. Gregariousness is made possible in almost all its forms by purposive expression. There comes early, then, a will, not merely in performing some definite act at prompting of a feeling, but also a use in simply expressing it to others, communicating the fact of having pain or pleasure states to others. The cry of pain in young animals is a cry for help, and as such has been favoured in the struggle for existence. The usefulness of this action is solely as expression, and as expression it has arisen and been developed. Expression here is not an incidental view of a physiological action, but exists for its own value to the individual. Such expressions have their use in their significance, and as the true language of feeling are to be interpreted by the principle of serviceability. An expression which is and continues, by reason of its utility, as a sign-language, visual, auditory, or otherwise, as gesture love-calls, etc., may be termed pure expression as distinguished from incidental expression, like blushing, pallor, etc., which exist, not for their significance, though they are significant. Incidental expression includes also the sphere of degraded action. Yet what seems mere degraded action may be true expression, as beckoning, which is an abridgement of the action of pulling one to oneself and of movement towards oneself; but this motion of the hands exists, not for this end, nor as survival, but merely as significant of a desire on the part of the gesturer. In the higher ranges of life we well know the large place played by pure expression as distinguished from incidental expression. It is not necessary to suppose that pure expression consists merely in “voluntary and consciously” employing “means of communication” (Darwin, Expression of the Emotions, p. 256); thus, the scream of 348an infant is equally pure expression, whether the infant employs it knowingly or not as such, for screaming of the young has doubtless arisen and been preserved in natural selection because of its utility as significant. There is then, I think, a group of activities which are not merely incidentally expressive, but originate and exist for expression as a useful thing in the battle of life.

But we have not exhausted the principles of expression when we refer to present or past serviceability as an action in general or to service as expression. It is plain that in any activity prompted by any feeling there comes at a certain high intensity a more or less pathologic over-functioning of the organs concerned, with under-functioning of others. Emotion as action stimulator in any high degree always enhances some physiologic function to the depression of others. The blood, for instance, is forcibly withdrawn from various parts to certain specially active parts, and this withdrawal gives rise to an appearance which may be termed a negative expression, as the pallor in fear. Certain other phenomena connected with fear, as change of colour in the hair, cold sweat, and trembling of the muscles, which are mentioned by Darwin as unexplained, are probably due to this negative principle (Expression of the Emotions in Man and Animals, New York, 1886, p. 350; but compare pp. 81 and 308, where these disturbances are ascribed to direct action of the nervous system. Darwin does not, however, distinctly state or treat the principle we here mention as a distinct law). As the body is an inter-related system of organs, stimulation to one organ means an effect upon all, excitation of some, depression of others; thus to an acute observer the whole body is symptomatic of every feeling, and, indeed, of every consciousness. In the natural and normal course emotion, to do its work most effectively, implies little or no marked negative expression, but the nervous energy generated flows freely and directly to the organs which 349are to do service, without greatly impairing general function. Fear thus acts at first simply and advantageously; but in its later history fear becomes greatly complicated, and instead of freely issuing in serviceable action with not excessive heightening or depressing of any function, its outlet seems as it were choked, and the nervous energy spends itself within the body in violent disturbances of vital organs. Fear becomes then decadent and loses its place as evolutionary factor, becoming impediment rather than aid to progress. Negative expression must then be considered as especially notable in the later exhibitions of an emotion when concentration becomes morbid and ineffective, losing its advantageousness, and the emotion is being supplanted by other psychic factors. Great injury and death itself may result from the abnormal action of fear and other primarily useful psychoses.

Besides the particular organs to serviceable activity with the subsidiary physiological functioning, and the indirect depression, we must still note other principles which may control expression. Nervous energy under the incitement of emotion is often in excess of the demand for the required action, and it will then overflow into correlated activities along the line of least resistance. Also when the suitable action is checked for any reason, its motive force backs up and overflows in new channels. Indefinite and purposeless movements of various kinds thus result which may be expressive of the emotion of which they are incidentally the result. Any one who has watched an Irish setter tracing game must have remarked the wavings of the tail becoming more rapid when the scent becomes stronger. When the dog is running very fast, the tail-waggings are less noticeable than when moving slowly, although the interest may seemingly be the same in both cases. It is obvious that a fast run uses to a large extent the superfluous energy which was discharging in tail movements, and when the useful running is 350checked the tail motion recommences with greater force, serving as a safety-valve. The frisking of young animals and children is also largely due to diffusion of so-called superfluous nerve-force, and is expressive of general sensations of pleasure. All feeling is motor in its natural value and tendency, and unless the resulting energy is fully used in some special serviceable action, it will discharge itself along the easiest and most habitual lines laid down by inheritance. Thus the peculiar ancestral experience of animals is always expressed by their spontaneous diffusive activities. It will be remarked that the principle of diffusion is the reverse of negative expression, being an overflow of force as opposed to withdrawal. Excessive generation of energy is certainly uneconomical, and we must consider that at first emotion tended rather to less than the required amount, than more.

The phenomena of diffusive expression, in the strict sense, are thus rather late in appearance. The very lowest forms of life have no infancy or play period, and from the first are directly active in the struggle for existence. Yet the play period was certainly evolved through natural selection as a fully educative and preparatory stage, wherein the actions most demanded in actual life are unconsciously practised and a general basis of reserve force is accumulated. Play activity is a living on inherited energy and in the inherited modes: the kitten pouncing, the horse prancing, etc. Play is then rather a mode of activity than a mode of expression; it is expressive only in the way that all action is expressive. Expression proper is only in those modes of action which are carried on, whether consciously or unconsciously, by virtue of their significance value. If everything which is expressive is called an expression, we must include all the bodily actions and phenomena which can in any wise be connected with consciousness. I use the term diffusion in the narrow sense of spontaneous overflow of energy in 351excess of that absolutely required for the advantageous action. I do not refer to the general diffusion of emotional effect throughout the whole organism, which always occurs by the very nature of organism. Thus the pain from a pin-prick certainly modifies to some extent every cell in the body; there is a direct wave of influence from the psychic experience, and this is propagated throughout the whole organism by reason of its essential interdependency of parts; it echoes and re-echoes throughout the whole. The physiological result is then in simplest cases extremely complicated. However, this mere general fact of diffusion is a biological truism, and does not explain any expression, but simply asserts that every feeling, by virtue of its physical basis, affects the organism as a whole. Emotion issues specially in motor activities because its origin was as stimulant to necessary action, but this action involved internal organs, especially the circulatory and respiratory, and indirectly the whole body in every part. The explanation of an expression must always be in tracing back to the original serviceable actions with their demands on special subsidiary organs, and their depression of certain related organs, and not in reference to the general law of diffusion, which is but another term for the essential continuity of the organism. A useful principle of expression must not merely say that there is by the nature of organism a general bodily result from every emotion, but it must explain the particular expressions.

We make them so far four principles or forms of expression, which we instance in saying that the blow of an angry man is general activity expression, shaking the fist at one, purposive expression, scowling as remnant of watching foe intently in the open air is survival expression, and twitching and trembling of certain muscles is diffusive expression. Every emotion commonly issues in all four forms, in direct activity with associated survival tendencies and purposive expression, and a surplus of energy runs 352over into certain natural and easy motions, or a deficiency of energy in certain organs manifests itself, the negative side of diffusive expression.[G]

G. Since emotion comes in waves, expression is reduplicated. This may throw some light on such an expression as laughter. Landor says the Ainu do not in the proper sense laugh, but they roar with delight. It may be that laughter is reiterated roar as resulting from reiterated psychic impulses and feelings. As in the growth of an emotion, waves are multiplied, the expression becomes more reduplicate, and thus laughter tends to become more rippling and articulate. The cachinnation and explosiveness has thus a plausible explanation, which I merely suggest. At least Prof. Dewey’s explanation (Psychological Review, I., 559) that “both crying and laughing fall under the same principle of action—the termination of a period of effort”—is quite too general. Tension ceasing, effort stopped, we “breathe freely,” take deep inspirations. Laughter is far from being the usual outcome of such a status.

Darwin makes antithesis a principle of expression. Thus the expression of affection in the dog or cat toward its master cannot, says Darwin, be traced in any wise to serviceability, and we must seek its explanation merely as unconsciously and instinctively assumed as directly contrary to the serviceable hostile expressions. A dog’s expression of anger is, or has been, directly serviceable action, but the expressions of affectionate pleasure seem never to have had such an origin, but to have arisen merely as antithetic to the former, and so establishing the utmost distinctness of impression. To convey most clearly a motion of its friendliness the dog naturally assumes those attitudes which are most diverse from its expression of hostility. Their serviceability as expressions is best attained by being completely antithetical, and the more antithetical the better under natural selection. However, if this be the case, antithesis scarcely deserves, it seems to me, the name of a principle of expression, but it merely denominates the fact that opposite emotions in the struggle for existence tend to exhibit themselves in opposite ways as similar emotions in similar ways; but 353we need neither antithesis nor similarity as a principle. I believe that serviceability past or present either as direct action or as expression is the prime impetus of what we term the expression of the emotions, and I confess I do not see much force in Darwin’s Chapter on Antithesis. If, however, opposition has a meaning for life, as Darwin seems to imply, then does not the expression come under the law of serviceability? If there is any opposition in expression, I should explain this in general by utility rather than by antithesis per se. Thus take the gestures instanced by Darwin (ibid., p. 65), of pushing away with the hand when telling one to go away, and of pulling toward when telling one to come; these gestures are, indeed, antithetic, but their explanation does not lie in the fact of the antithesis, but in the fact of the past serviceable habit, by which individuals disliked or liked were repelled or attracted. In the present instance the person motioned to may be far beyond the reach of the arms, but still the gesture may be more than mere useless survival, for it acts as emphasis of the vocal expression, and has its influence there.

Darwin for some reason constantly ignores the serviceability of expression as such—not so much as a fact, but as a principle—and hence its relation to natural selection, whereby he involves himself in needless difficulties. If an expression is of use, why should it not arise through natural selection as well as a limb, a wing, or an eye? Like other functions, expression may be incidental or may adapt variations attained originally for other ends, but in the case of the voice, at least, we have an original organ of expression as instrument of intercommunication.

Nor can I think Darwin’s treatment of the expressions of affection by the dog as due to antithesis a very happy or satisfactory solution. In the first place, the expression of friendliness by the dog is not the complete antithesis of that of hostility. The dog barks both out of friendly 354joy and from anger, as Darwin himself states. Some dogs also, as I have often observed in my dog, show pleasurable affection by wrinkling up the lips and showing the teeth, an act which is often mistaken for a hostile demonstration. Dogs also, as is the habit with my own, will often express affection in the same way as the cat (ibid., fig. 10), by rubbing against one. This is but an instance of a general law of expression of affectionate emotion, i.e., closeness of contact with the beloved object which is liked as promoting pleasure. This instinctive expression of love or liking certainly had its origin in serviceability, the appropriate effort toward the pleasure-giving thing or animal, but specially in the relation of parent and offspring, and in that of alliance in danger. Again, the tail of a hostile dog is, as figured by Darwin, straight and erect, but the opposite of this is the tail tucked between the legs when fleeing from pursuers in fear, rather than the position when showing friendliness to its master. My own opinion of the rise of the friendly expression of dog, cat, and other animals toward man is that they are in the main, at least, transferred from the serviceable friendly expressions used among themselves in a wild or domesticated state. I have repeatedly seen small dogs, who attach themselves to some large dog as their master, fawn, posture, and lick this master precisely as this master does his human master. Dogs and cats also show their affection and care for their offspring in many expressive acts which are transferred to their human owners. These expressions were primarily either directly serviceable actions, as the licking, or serviceable for expression as such, as various sounds made to give assurance of presence of food, or of safety. In general, it seems to me that when antithesis has occurred, it has arisen out of serviceability and not vice versa.

With reference to the wagging of the tail in the dog, this is far from being an expression of affection alone. I have already mentioned the case of the setter where the 355movement of the tail is largely due to diffusion of superfluous energy, analogous to nervous habits like pacing the floor or biting the nails in human beings. With some dogs at least, as I have noticed in my own St. Bernard, the tail is switched slowly back and forth when approaching another dog with hostile intent. We have not as yet a sufficient number of facts at hand with reference to the history of the dog to pronounce the tail wagging as originating by virtue of its use as expression. And what is the rationale of the origin of the tail in the dog and cat, and for what reason has it been perpetuated? Is it a prehensile survival—which has been taken advantage of in the breeding of the pug—or is it a sexual characteristic, or did it originate to perform some directly advantageous action, as the tail of the cow and horse, or did it come into being as an organ of expression? Is the tail-wagging recognised by animals themselves as an expression as it is by man? These are questions on which we must have more data than we now possess in order to make any sufficient answers.

Again, the rise of the barking by dogs under domestication is another problem on which little can be said with certainty for lack of data. Darwin’s remark that it may arise by imitation of the loquacity of man seems to me ludicrously inadequate, and there seems no element of imitation in the noise produced. Domesticated animals in general tend to use the vocal organs for louder sounds than when in the wild state, for with wild animals the value of a loud noise as expression in any way is largely counterbalanced by its betraying presence to enemies. When natural enemies of the dog are driven out by man there will be a tendency toward a larger use of the vocal organs, both with reference to companion dogs and also to man. The particular sound, the bark, is determined by the nature of the whole vocal apparatus. The bark was, no doubt, originally to frighten aggressors, 356as I have often seen a large dog frighten a small dog from a piece of meat by a sudden resounding bark. Gradually attained as a mode of terrifying his competitive associates and certain game which it follows under domestication, and so preserved and developed by natural selection, the tendency is also powerfully strengthened by artificial selection, the best barker, other things being equal, being chosen for breeding by man. When the bark has become a common and habitual practice, it becomes a vent for superfluous energy developed by joy and other emotions. Like snarling or grinning, it is also a play form, and thus becomes denotative of joy by association. To impress one’s friendliness or hostility upon others, to appease or terrify, are the two main ends of expression with both man and animals, and this function is excited in various ways by different species, as determined by environment. The danger signal and the safety signal, the beware or welcome, is amplified and varied according to particular requirements which must be fully investigated before we can give any complete rationale of any expression. Conciliatory and menacing expressions and gestures have been evolved and matured in strict correlation under the same general law of natural selection, and neither one nor the other is due to antithesis. It is entirely unlikely that of such expressions, one, the hostility side, was first developed by natural selection, the other owing its rise to a distinct principle, antithesis.

However, I am not ready to deny antithesis all force as principle of expression, but it seems to me it should be ranged with law of similarity or analogy as subsidiary, and largely influential only in the higher types of expression, especially the teleologic human, as in gesture. Thus, if thumbs up means pity, thumbs down would naturally be used to denote pitilessness. To nod the head means assent or yes, to shake the head means dissent or no, though the exact antithesis would be to throw the head 357backward—assent signal with some tribes. However, while it may be asserted that, as a general law, that like emotions express themselves in like ways, unlike in unlike, this can hardly be used to throw much light on expression. Given a particular emotion and its expression, we can by no means deduce immediately the expression of the opposition emotion. Particular conditions and special organic limitations will always make this impracticable, and it is the office of the scientist to study expression in the course of evolution as of service under a multitude of conflicting interests and distracting difficulties.

We view expression then as mainly due to the principle of advantageous variation in the struggle for existence. Expression is the action required in the battle for life, or accompaniments to assist this action, or the call for aid to bring it about. Natural selection is the first and fundamental law of expression, negative expression and superfluous energy both being secondary and often pathologic in tendency.

The struggle for existence is itself on the very face of it an expression of mind, namely, activity significant of certain will and feeling experience. Whatever shows mind is expression, and thus in a large sense every movement in the physical universe—and what is the universe but motion&md............