Few other organs lend themselves to such emotionally charged discussion as the color of the skin. Egalitarians have been quick to accept the recent dogma that skin pigmentation has no biologically social significance; rather, they argue, it is an adaptation to protect us from the sun. In areas where the sun is usually obscured by clouds, people are said to be lightly pigmented to allow more efficient Vitamin D synthesis. This, if true, is nevertheless only part of the story. A sunshade isn't going to cause that much social upheaval. We are uptight about skin color because it is a major organ of communication stretching back hundreds of millions of years through our ancestry. Before examining human skin color, it would be best to take a brief look at the importance of coloration in other species.
Some fish communicate with the skin. They contract minuscule color cells that dramatically create, destroy and recreate other patterns. One second the fish is bright red in threat, the next second it flees and blanches completely silver-white. In one social situation spots or artificial eyes are displayed, in another situation it is striped; each carries a different social signal. Reptiles, especially lizards, also use the skin for communication by varying their color pigments. The little American "chameleon" is an excellent example. Dominant males distend their red throat wattles, raise their skin hackles, and turn black. The subordinate color is a pale, washed out green.
Many species of fish, amphibians and reptiles use the skin colors to signal mood changes. A species of fish, the cichlid is shown here in a variety of social colors, each having a certain meaning and used in a certain context.
Mammals have lost the expandable color cells. With the coming of hair most of the bare skin was covered. But color continued to be of utmost social importance. In addition to direct skin color, pigment was laid down in the hair shafts, but since hair is a dead tissue, its colors must be limited to changes in seasonal moults (it may bleach some with time, but hair "turning white with fright" is an old wives' tale).
A dark coloration seems to have intimidating qualities when one looks across the spectrum of mammalian social coloring. Whenever there is a sexual difference, the dominant sex, the male, is the darker. There are very few exceptions to this, mainly in instances where contrast seems to override color, as in the case of the dark bull caribou's white neck mane. In the evolution of some mammals (and birds) the base skin has been exposed and functions as a flexible color signal. Bare skin can be changed rapidly and dramatically, even without the use of special color cells, by flooding the surface capillaries with blood so it becomes a crimson red. The capillaries can be drained and the skin blanches light again. Human reddening in anger functions in this fashion.
Among the other primate groups, skin or pelage color is virtually independent of solar exposure. For example, the mountain gorilla has a deep jet black skin as well as do some South American monkeys, yet both live in deep forests and spend only a small fraction of their time out in the bright sun. The Hamadryas baboon, on the other hand, is exposed to the intense glare of the Ethiopian dry country and has very little skin pigment.
The correlation between skin pigmentation and sun exposure among human groups is also rather poor. No doubt skin pigments do serve some physiological function in screening out damaging sun rays. Skin protection is surely a factor in skin pigment evolution, but it is only one factor - and there are times when its role seems to be minor at best. Some peoples who live in areas where there is intense solar radiation are as light as some living in areas where there is little. Compare, for example, light-skinned Arabs from the desert country with the dark natives in the deep forests of Borneo or the pygmies of the central Congo.
The threat value of dark skin probably has arisen indirectly from its role as a protector for the sensitive generative layer of the skin from ultraviolet excesses. The greater the exposure to ultraviolet, the more the melanin pigment cells proliferate - the darker the skin. Some of this is cumulative, so a person exposed to the sun all his life is darker than his well-tanned stage when young. There is then an age gradient in most groups relating to skin color. And since the social hierarchy corresponds to the age hierarchy the pattern for social color is somewhat inherent.
But there is something more. We are diurnal, that is, daytime, organisms, and we function at night only with an artificial sun - a fire, lantern, or incandescent lamp. Our eyes are daytime eyes and perform poorly at night. Eckhard Hess has suggested that because our pupils are small when we are discouraged or depressed (things "look black") we are actually receiving less light onto the retina. We come to associate darkness then, with bad times and light with good times. There is something mystical, unknown, mysterious about darkness. Black is foreboding, as in "gathering black clouds." The complex mind of man couldn't have helped but make these associations in nature. Black is a synonym for sinister: Black Bart, Bluebeard, the Black Demon, the Black Knight, and the black hats in cowboy movies. Black is aggressive, a Karate belt, and Dracula's cape or even a black nightie. White is submissive, as in a white flag, a white dove, and a wedding dress.
Quite often young or juvenile animals are colored opposite to the adult. In many cases this different coloration gives the young some protection from adult aggression. It is a signal that there is no real threat, even though it is a member of the same species. In many cases the adult must be white for reasons of protective coloration or some other factor, as in white gulls or white beluga whales. Their young are much darker than the adults, unlike the apes, where adults are characteristically dark and the young light. So the uses of a dark pelt as the signal of dominance is not universal among mammals. There are apparently a number of things which can override the threat value of darkness. The chief ones seem to be cases in which the adult must be white for some other, more important reason, say in concealment or cases in which light areas expand over the body due to their contrast value, such as in graying.
The variation in color patterns among the different gibbons, light limbed brachiating apes from Southeast Asia, provides the best evidence for color changes and their uses within age classes and between sexes. Fooden has concluded that the early gibbons were a homogeneous brown (like the living gibbon species, Hylobates moloch, which varies somewhat in shades of brown). From here, he feels, there evolved two color phases of light and dark that were originally not separated according to sex (as in the living species, H. lar entelloides). However, the light forms were apparently selected for in the females but selected against in the males (as in the species H. concolor and H. hooloch) so that all females were cream and all males black. The most extreme form of this apparent trend is in the species H. lar pileatus, when young are born paleface and darken with age. The males continue to darken at maturity, whereas the females at maturity revert to the pale phase.
In the Gibbon species, Hylobates lar pileatus, whiteness becomes associated with subordinate social stature and carries an obvious signal of rank. It benefits the possessor because it would not provoke the black males. Whiteness in a male of this subspecies would result in his being a "sissy," treated either like a juvenile or a female, which in the rank system of most mammals spells "subordinate".
What has happened, as in the gibbon species Hylobates lar pileatus, is that there were pressures to create sharper differences between sexes and the immature and mature. Human beings show these same color differences, only more subtly.
Gilbert and Sullivan should have written, "Only mad dogs and red Englishmen go out in the noonday sun". We are conditioned to think of Northwestern European stock as cream colored because they are now an indoor people, and those who work outside wear clothes to shade their bodies and hats to shade their brows. But one can catch snatches of what they must have looked like when they were outdoor people. The rowcrop farmers of the midwest wear billed caps, and in late summer it is spectacular to look out over an indoor gathering, where hats are removed. The women are softly tanned from occasional forays to the garden, but the men's faces are studies in contrasts. The lower face from the cheeks on down is a rich rusty brown, but the forehead shines ivory white. There are a few old men who have worked out in the sun year-round all their lives, and they are far from fair.
It's an odd quirk of fate that the white man came to the New World clothed and wearing a broad-brimmed hat; otherwise he would have been called the red man. Western Europeans tan a burnished copper red; Orientals, which ancestry the American Indians share, tan a soft brown.
In virtually every society where there are well-developed social classes or castes, and color differences as well, the lower classes are the darker (in the same way that lower classes tend to be hairier); not because these castes are in any way inherently inferior, but because the neotenization process in social ornamentation is more extreme in the higher classes. Hulse has found strong selection pressures for skin color among modern Japanese, along with sexual differences. Japanese have an outspoken admiration for white skin, particularly in women, and they have a long tradition of whitening the skin with powder, as do many Occidental cultures.
In very light-skinned peoples, veins immediately beneath the skin appear bluish through an almost transparent skin, giving rise to the myth that venous blood is blue. I suspect that the combination of light skin being associated with high status and the bluish appearance produced the designation "blueblood" for people of aristocratic birth.
The current slogan "Black is beautiful" really means "Americans of African ancestry are beautiful people" - a legitimate attempt to remold the values of Blacks into realizing they are just as beautiful as all of the white models which have determined American's taste for years. But within a more homogeneous subgroup, saying "black is beautiful" is like saying big beards are beautiful - it all depends on whether and how that society is currently emphasizing the more blatant status signals or the gentility of soft, babyish appearance.
For example, the reversal of the fair-lady mystique after World War 11 happened as the result of those with leisure being able to swim in the sun or vacation in Miami. A tan symbolized, like white sneakers, crew socks, and polo shirts, that one had the leisure for sports. A brown, svelte swimmer no longer carried the stigma of a dark wench. I suspect that this shift is only temporary perturbation of the whole complex of the human neotenic. Though these changes in our values often appear to be erratic through history I suspect they follow definite patterns. A change in style, cosmetic habit, or the ideal figure, though superficial and arbitrary on the surface, may be deeply tangled in the zeitgeist and tied even more deeply in our biological values about appearances.
Skin colors can change rapidly by varying the amount of blood in the skin. There seem to be three themes in the evolution of human communication through flushing the skin with blood. There are (1) the anger flush, (2) the blush, and (3) the sexual flush. The anger flush is an old tradition used today by many non-human primates. It is far from vestigial in humans, but there is considerable variation in its expression among human subgroups and within them. Physicians often refer to flushers and blushers as vascularly unstable. It is part of a syndrome characteristic of the blue-eyed, pink-eared, freckled palm-sweaters of Northern European ancestry. In groups without very dark pigmentation it is common enough to be generally recognized as a signal of internal mood. The more swarthy human subgroups are not as prone to skin flushing with mood changes.
Like the anger flush, there appears to be some within-group and between-group variation among blushers. Daniel Freedman, in his comparative study of small children, found that "The Navajo infants exhibited two outstanding differences from all other groups, a tendency for the entire body to become red when excited and to remain that way for much of the examination . . ."
The third type of reddening is the sexual flush which was emphasized by Masters and Johnson. In the adrenaline peak of the sexual excitement, it is common for many Caucasians to flush red over most of the body: in keeping with an old primate tradition, a splash of red is synonymous with sexual decoration among females.
One might think that these three social signals all employing skin reddening but having quite different meanings and evolutionary histories might become confusing. However, they seldom do. Probably it is because the contexts in which they are used are dramatically different.
It is strange that one could redden both in anger and in subordination and still keep the meanings separate. Yet we've seen that in the submissive grimace among carnivores the teeth are bared to the opponent, almost as they are in a snarl. Differences in situation and pattern keep the meaning of submission and threat quite clear. These signal values are further complicated by the process we discussed earlier of Caucasoid reddening to a new-copper tan with exposure to the sun, which seems to be a more permanent form of anger flush - a badge of dominance (what the rosy cheek is to the subordinative blush). The deeply tanned person loses some flexibility in his social signals and dark-skinned groups have also lost the flexibility to communicate mood with skin color, as the moustached man has lost some visual symbols of his lips.