The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature (44 page)

with William Henry Perkins's synthesis of "mauve" in 1856.

Before modern dyes and pigments were available, it was very difficult to obtain the materials necessary to produce large

areas of saturated color, whether on textiles, paintings, or

buildings. When Alexander the Great sacked the royal treasury of the Persian capital Susa in 331 B.C., its most

valuable contents were a set of 200-year-old purple robes. By

the 4th century A.D., cloth dyed with "purpura" (a purple dye obtained from the murex mollusk) cost about four times its

weight in gold, and Emperor Theodosium of Byzantium

forbade its use except by the Imperial family, on pain of death. Colorful objects were considered beautiful, not least because

they reliably indicated resourcefulness—our ancestors faced

the same problem of finding colorful ornaments as the bowerbirds. Nowadays, every middle-class family can paint

their house turquoise, drive a metallic silver car, wear

fluorescent orange jackets, collect reams of glossy color magazines, paint the cat crimson, and dye the dog blue. Color

comes cheap now, but it was rare and costly to display in art and ornament during most of human evolution. Our ancestors did not live in a sepia-tint monochrome: they had their black skins, their red blood, the green hills of Africa, the blue night, and the silver moon. But they could not bring natural colors under their artistic control very easily. Those who could may have been respected for it.

Before the age of mechanical reproduction, ornaments and works of art could display their creator's fitness through the precision of ornament and the accuracy of representation. Modern technology has undermined this ancient signaling system by making precision and accuracy cheap, creating tension between evolved aesthetics and learned aesthetics. Our evolved folk aesthetics still value ornamental precision, representational accuracy, bright coloration, and other traditional fitness indicators. But we have learnt a new set of consumerist principles based on market values. Since handmade works are usually more expensive than machine-made products, we learn to value indicators of traditional craftsmanship even when such indicators (crude ornamentation, random errors, uneven surface, irregular form, incoherent design) conflict with our evolved preferences. Yet within the domain of manufactured goods, we still need to use our folk preferences to discern well-machined goods from poorly machined goods. This can lead to confusion.

For example, there was a famous case in 1926 when Constantin Brancusi sent his streamlined bronze sculpture "Bird in Space" from Europe to New York for an exhibition. A U.S. Customs official tried to impose a 40 percent import duty on the object, arguing that it did not resemble a real bird, so should be classed as a dutiable machine part rather than a duty-free work of art. Following months of testimony from artists and critics sympathetic to modernism, the judge ruled in favor of Brancusi,

stating that the work "is beautiful, and while some difficulty might be encountered in associating it with a bird, it is nevertheless

pleasing to look at." Although "Bird in Space" exhibited a

perfection of form and finish that Pleistocene hominids would

have worshiped, it was almost too perfect to count as art in our

age.

Handaxes as Ornaments

Stone handaxes show that hominids did care about form and finish. Indeed, science writer Marek Kohn and archeologist Steven Mithen independently developed the theory that sexual

selection favored symmetric handaxes as fitness indicators. If their arguments work, handaxes represent the first hominid works of art, and the first hard evidence of sexual selection shaping human material culture.

Two and a half million years ago, our small-brained ancestors evolved the ability to knock flakes from rocks to use as cutting edges. By doing so, they could also make the rocks themselves useful as choppers. This basic tool kit of flakes and choppers served the needs of hunting and gathering for a million years. Then, around 1.6 million years ago, a medium-brained African hominid (
Homo erectus
) evolved the ability to produce an extraordinary object that archeologists call a handaxe. A handaxe is a rock chipped into roughly the size and shape of a child's hand—flat with fingers together. There is a sharp edge all around and a point at the tip. The outline is midway between that of a pear and a triangle. The top and bottom faces are symmetrical (handaxes are also called "bifaces"), as are the right and left halves. Most were made of flint, some of quartzite or obsidian.

Handaxes proved enormously popular. They were made for over a million years, until about 200,000 years ago, by which time our ancestors had evolved into large-brained archaic
Homo sapiens.
Handaxes were made throughout Africa, Europe, and Asia, and in enormous numbers: sometimes hundreds are found at a single dig site. The persistence of a single design across such a span of space and time cannot be explained through cultural imitation. Designs passed down through mere imitation tend to deviate further and further from the original prototype, as languages do over hundreds of years. Handaxes must have been to hominids what bowers are to bowerbirds: part of their extended phenotype, a genetically inherited propensity to construct a certain type of object.

But why did the handaxe evolve? Handaxes are not particularly bad tools. They offer a fair amount of cutting edge for their weight, and they are somewhat safer and easier to use than flakes when butchering large animals. But the cutting edge all the way around the rim makes a handaxe rather difficult to hold, like a

knife without a handle. For almost all practical purposes, sharp flakes and edged choppers would have been sufficient.

Perhaps handaxes were missiles rather than hand-held tools? H. G. Wells proposed in 1899 that handaxes may have been thrown at prey but this "killer Frisbee hypothesis" has not fared well. In 1997, in a coal mine in Schöningen, Germany, archeologists found some well-preserved, six-foot-long sprucewood spears. They were almost as well engineered as modern javelins, quite lethal, and 400,000 years old. Given that such excellent missiles had been developed by that date, why did our ancestors keep making handaxes for another 200,000 years?

Some handaxes may have been practical tools, but Kohn and Mithen noted that many show evidence of skill, design, and symmetry far beyond the demands of utility. Some were made in large sizes too heavy and clumsy to use. The "Furze Platt Giant" handaxe is over a foot long, and seems designed to be held in both hands and admired. Others are under two inches long, too small to be of much use. Often they show far more exact symmetry than seems necessary, and, from a practical viewpoint, excessive attention to the regularity of form and finish. Handaxes were often made in very large numbers in the same place. Most importantly, many of the finest handaxes show no sign of use: no visible chips, and no evidence of edge wear under the electron microscope. Why were so many handaxes made so perfectly, with such care, and then discarded, apparently unused, still sharp enough to cut fingers a million years later?

In his book
As We Know It,
Marek Kohn argued that the handaxe "is a highly visible indicator of fitness, and so becomes a criterion of mate choice." Handaxes make good Zahavian handicaps. They impose high learning costs: it takes six months to acquire the basics of flint-knapping, and years more to perfect the skill. They take extra time to make. Modern experts with 25 years of flint-knapping experience take about 20 minutes to make a decent handaxe, whereas a simple edged tool can be made in just a couple of minutes. There are risks of injury: modern flintknappers wear boots, leather aprons, and goggles to protect

against flying rock shards, and they often get cuts on their hands. Expert handaxe production requires a combination of physical strength, hand-eye coordination, careful planning, conscientious patience, pain tolerance (to deal with the flying debris), and resistance to infection (to deal with the cuts)—as Kohn noted, "A handaxe is a measure of strength, skill and character." Their symmetry, like that of the peacock's tail and the human face, makes their perfection of form very easy to assess, but very hard to produce. In short, handaxes are reliable indicators of many physical and mental aspects of fitness. Kohn suggested that the normal, pragmatic handaxes may have been fashioned by females, while the very large, very small and very symmetrical ones were produced by males as sexual displays.

So, we have an object that looks like a practical survival tool at first glance, but that has been modified in important ways to

function as a costly fitness indicator. Kohn and Mithen have made a fairly good case that the handaxe was often a work of art, and a sexual attractant. They suggested several ways to test their hypothesis further. If their radical idea proves correct, then handaxes may have been the first art-objects produced by our ancestors, and the best examples of sexual selection favoring the capacity for art. In one neat package, the handaxe combines instinct and learning, strength and skill, blood and flint, sex and survival, art and craft, familiarity and mystery. One might even view all of recorded art history as a footnote to the handaxe, which reigned a hundred times as long.

9

Virtues of Good Breeding

Murder, unkindness, rape, rudeness, failure to help the injured, fraud, racism, war crimes, driving on the wrong side of the road, failing to leave a tip in a restaurant, and cheating at sports. What do they have in common? A moral philosopher might say that they are all examples of immoral behavior. But they are also things we would not normally brag about on a first date, and things we would not wish an established sexual partner to find out that we had done. The philosopher's answer sounds serious and mine sounds flippant. But the philosopher's answer does not identify any selection pressure that could explain the evolution of human morality Mine does: sexual choice.

Most evolutionary psychologists have viewed human morality as a question of altruism, and have tried to explain altruism as a side-effect of instincts for nepotism (kindness to blood relatives) or reciprocity (kindness to those who may reciprocate). I think human morality is much more likely to be a direct result of sexual selection. We have the capacity for moral behavior and moral judgments today because our ancestors favored sexual partners who were kind, generous, helpful, and fair. We still have the same preferences. David Buss's study of global sexual preferences found that "kindness" was the single most important feature desired in a sexual partner by both men and women in every one of. the 37 cultures he studied. It ranked above intelligence, above beauty, and above status.

Oscar Wilde's play
An Ideal Husband
recognized the role of sexual choice in shaping human morality. The drama's theme is that men and women are under very strong pressure to make a

credible show of high moral stature to their lovers and spouses. The drama centers on this: will the highly principled Lady Chiltern still love her husband after learning that he acquired his fortune by selling a government secret? Wilde put his finger on an evolutionary pressure for morality that has not yet received sufficient attention in evolutionary psychology: good moral character is sexually attractive and romantically inspiring. Conversely, liars and cheats are sexually repulsive—unless they have other charms that compensate for their flawed character. In the play, Sir Robert Chiltern retained his wife's affection only by making a parliamentary speech against an investment swindle—a public moral display which, due to the threat of blackmail by the swindlers, he believed would cost him his career.

As we have seen again and again in this book, sexual attractiveness alone is sufficient to explain the evolution of many traits. One does not always have to seek a survival function. Many theorists have tried and failed to trace human morality to various survival benefits for the individual or the group. I shall argue that some of our most valued moral virtues had no survival benefits, but they did have strong courtship benefits. Sexual selection enables us to explain a class of moral behaviors and moral judgments much broader than those considered by most philosophers and evolutionary psychologists. A sexual selection perspective allows us to explain sympathy, agreeableness, moral leadership, sexual fidelity, good parenting, charitable generosity, sportsmanship, and our ambitions to provide for the common good. The importance of sexual choice in the evolution of human morality, generosity, magnanimity, and leadership has also been analyzed by biologist Irwin Tessman, anthropologists Kristen Hawkes and James Boone, and primatologist Frans de Waal. I draw on many of their ideas in this chapter.

Human morality, in my view, includes any behavior that displays good moral character. It is not limited to altruism, which is the conferral of a benefit on someone else at an apparent cost to oneself. Displays of altruism can be among the most potent displays of moral character, but they are not the only such

displays. As with most reliable fitness indicators, the point of moral displays is not so much the benefit conferred on others, but the cost imposed on oneself. Morality is a system of sexually selected handicaps—costly indicators that advertise our moral character.

Apathy as the Evolutionary Norm

According to a popular stereotype, evolutionary theory implies that organisms should engage in rampant, bloody, unrestrained competition. If we take any two animals from anywhere in the world and throw them in a pit, they should start tearing each other apart. Yet they do not. Does this imply that nature is more cooperative than evolution can explain?

No. Ecologists have long understood that the typical interaction between any two individuals or species is neither competition nor cooperation, but neutralism. Neutralism means apathy: the animals just ignore each other. If their paths threaten to cross, they get out of each other's way Anything else usually takes too much energy. Being nasty has costs, and being nice has costs, and animals evolve to avoid costs whenever possible. This is why watching wild animals interact is usually like watching preoccupied commuters trying to get to work without bumping into one another, rather than watching a John Woo action film with a triple-figure body count.