Your eyes are deep as the Devon Springs,
Your hair as dark as jet,
Your years are few, your life is new,
Your soul untried, and yet-Our trail is on the Kimmeridge clay
And the scarp of the Purbeck flags;
We have left our bones in the Bagshot stones
And deep in the Coralline crags...-"Evolution," J. Langdon Smith
In the beginning some things were in limited supply, and it has remained so. The story of evolution is how some lines of organisms were able to continue in spite of this fact and be changed because of it. This is true of social behavior as well as of more physical adaptations.
If one could point to a dominant theme in the evolution of social behavior, it would be finding solutions to the problem of distribution of commodities in limited supply - that is, the distribution of privilege. Access to these commodities - food, water, mates, nest sites, etc. - is seldom equally distributed among the group. Status has its rewards and is virtually synonymous with privilege. It affects almost every animal's interaction with others and is probably the main force in his struggle to avoid death and to mate.
The more violent signals of rank are ballyhooed in popular literature, but in most species the usual rank signals and responses are more subtle. They are an ever-present part of social behaviors - a tilt of the head, a quick glance held only momentarily, a change in tail position, a few steps, a wrinkle of the nose, a twist of the ear. Photogenic, dramatic displays of mock and real battles are a minor part of social signaling. It is difficult to study a lingering odor on a trail, but such is the new material of the diligent field ethologist
Success to a particular individual may be measured in a degree of comfort or length of life. But in evolutionary terms, success is the relative genetic contribution to future generations one's evolutionary fitness. Having offspring isn't enough: they must be reared to reproductive maturity and in turn rear their young. Living a long time usually is, but need not be, relevant to fitness. If one lives to be a hundred yet has no offspring, his evolutionary fitness is zero.
Thinking about the how's and why's of natural selection is a more interesting way of looking at biological characteristics than trying to pinpoint their immediate function. You may ask whv are you bald? Or why are your nipples so pink? The evolutionary question becomes why, statistically, were balding males and pink-nippled females able to rear more young to reproductive maturity? (We can judge that once in our ancestral line, prior to the appearance of these "fit" problems, no one had bald scalps or pink nipples - by comparing an array of related primates.) So we look for a reason why certain types of scalps and nipples would increase reproductive success. And the same goes for other characteristics used to assist in communicating things that matter most in the lives of animals.
The ability to leave offspring is not dependent on how an animal deals only with his physical environment but also with his social environment. Sexual attractiveness is an obvious advantage but mainly, evolutionary fitness is dependent on social rank.
How did the behavior associated with obtaining privilege evolve? We are beginning to get enough information to piece together some possible answers.
There is quite a bit of evidence that aggression in many species does have an inherited component. Domestic strains of the same species vary considerably in general aggression levels; for example, beagles are low and Doberman pinchers high. The same is true for other domestic species, even for strains of laboratory mice or for farm foxes. One can select for aggression within a given strain and get a response - that is, make the next generation more aggressive, and the next, and the next.
The fact that lines of animal generally do not become more aggressive with time indicates that there must be some detrimental aspects of aggression. Very aggressive individuals must raise fewer offspring to maturity. As strange as it may seem at first glance, it is sometimes to one's reproductive advantage to submit and let the other fellow assume the more privileged position. Someday, "maybe next year," that thin-bodied virgin bull moose in the willows will have the weaponry of the big bull with the large antlers and will have all the ladies as well. It may be poor strategy to try to get some of the booty at all costs and not invest a few hopes in the future. Individuals who recognize their inferiority in combat, in most instances, will stand a better chance of leaving more offspring if they admit defeat. They can wait on the sidelines to re-enter competition at a later date when they have grown larger and stronger, when they can establish themselves on a territory earlier, or when higher-ranking individuals have become debilitated or have died. Hence submission can be directly related to an individual's fitness advantage, and not necessarily something done for the public good or the benefit of the species.
Some of the more revealing parts of the evolution of one's behavior regarding status and its anatomical aids lie in the origin of the signals themselves. In the signals of aggression and submission there are some common themes running through the behavior of almost all animal species.
One’s social state seems to depend mainly on four major elements whose importance varies and blends with different species and individuals. These are confidence, age, size, and sex. In ethological studies these are the recurrent themes that affect an individual's position in the social hierarchy.
It is the general rule among vertebrates, with only a few exceptions, that dominant individuals tend to be experienced, large, older males - and human beings are not one of the exceptions.
If it is advantageous to both parties in a conflict to assess their opponent's status properly in reference to themselves, it is not surprising that many displays for communicating social posit ion have evolved. Displays are stylized gestures or positions used to communicate pieces of information. Status displays of most vertebrates, including man take root from the four main themes affecting social status.
If one wishes to signal dominance, the gestures relevant to the real qualities affecting status are used. An increase in animal size is almost universally recognized as signal of aggression. Height in humans has hidden values far beyond being able to reach the Post Toasties on the top shelf. If one wishes to show aggression he inhales and swells up as large as he possibly can: muscles are flexed, crests raised, appendages extended.
The individual usually shows confidence in carriage and manner. Age and size are developmentally related, but deference is often given to age by the equally large but younger individual. The sex role is also deeply intertwined with social stature and the amount of aggression or submission displayed. Obviously, aggressive signals are the more masculine gestures.
Signals of submission have developed in the opposite direction. To submit, one becomes as small as possible, even making oneself prostrate in many species. Fins are sleeked, crests and appendages drawn near the body. Many which display the back and dorsal crest roll over in a "belly-up" submissive display. In submitting, individuals of many species often regress through the age spectrum, using juvenile utterances and gestures Notice your different attitudes toward adults with squeaky, adolescent voices and those with a rich radio-announcer bass. A common theme of submission signals is for the animal to act in female role; in some species, both sexes use a copulatory invitation of rump display when dominants approach them.
In many species recognition of these signals of status seems to be "built-in," requiring very little previous conditioning; among others, their lives follow a pattern which makes learning so situationally inherent that it may be difficult to separate the different origins of their behavior. F or example, the use of height in human threat for status displays as one necessarily moves through a great part of his physical development - first as a baby, then a toddler, preschooler, juvenile, teenager, etc. - equating height with status, for there is an almost perfect correlation up until reproductive maturity. Little wonder that he carries this attitude into his adult life.
In general, however, human status signals have evolved to be very flexible. A species with so plastic a life history as man would be incompatible with a fixed program dictating a precise format for his social life. But we are not alone in this regard: many if not most species have several ways in which they can communicate status. In the wildebeest, lechwe, and kob antelope, for example, small territories are used in some instances, but in other social and physical environments different expressions of status occur. Territoriality is certainly an important element in human ethology, but it is only a sub-element in a vast array of forms of status behavior involving physical acquisitions, knowledge, birthright, group identity, spouse and family, profession, hobbies, tastes, accent, graciousness, and on down a very long list, which is probably headed by appearance.
The evolution of our appearance is not just a study of the old bones of the past: It is a study of the sweep of time to the present. Social selection has not only occurred, it is occurring - it is across the tracks, down the street, next door, and in our own bedrooms. We are accustomed to equating natural selection with evolution, sometime back in the past, but this is not true. As selection is the difference in net-reproduction, and as in no populations, whether humans or boll weevils, do all individuals reproduce equally, a dynamic interplay is going on continuously.
The famous English ornithologist, David Lack, and numerous others since, illustrated how this interplay works. Lack counted the number of eggs in starling nests and found that the clutch size that produced the most young which actually left the nest was neither the large clutch nor the small, but ones near average size. Only in years when insects were very abundant were the starlings with large clutches able to find enough insects to feed all their young well, so that most could live until, they were old enough to leave the nest. This is a general principle: those individuals clustering around the middle do relatively more reproducing, while those on the extremes do least; as long as this is symmetrical, no evolution takes place, even though the selection process may be intense. In other words, the opposing selection forces are balanced. But since most things are so inconstant, these pressures seldom remain static for long, but shift and alter with the year and the season, and probably with the hour.
Using this as a background, we can look at the evolution of human social behavior and the accompanying organic social trappings in a somewhat different light. We are only grabbing a passing glimpse at an immensely complex and dynamic process. At this moment your fitness is dependent not only upon your behavior, but upon the color and texture of your skin, your height, ankle thickness, and so on to include your every contour.
If the fundamental theme in the evolution of social behavior is the sorting out of privilege, a close runner-up would surely be the theme of sexual behavior, or, let's say, behavior directed toward copulation. If one is to leave offspring, he must necessarily have incentives to procreate. These sexual patterns, like the status patterns, assume quite varied forms in different species. Usually they center on getting the two sexes together. Special calls, odors, or color patterns are used. Many social organs have evolved as a result of these forces of sexual attraction. Many of the organs human beings carry around with them function mainly as sexual attractants.
The young must be cared for in many animals (especially man). Our attraction to children and the need to give them attention become intertwined with sex and status in a beautiful fashion. There are even special human organs which have evolved to assist our child-love. They too have had their effect on adult organs of status and sex.
These diverse aspects of status, parent-offspring, and sexual behavior show up as dominant themes of our social, anatomy - the organs responsible for how we appear to others, or are privileged to make love to them.