The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature (42 page)

tightly interwined, as he himself was aware. The old punk song was right about Picasso: "He was only 5 foot 3, but girls could not resist his stare,"

Still, the extreme sexual success of modern professional painters like Modigliani, Gauguin, and Picasso would not have been the Pleistocene norm. It is unlikely that there were professionals of any sort during most of human evolution, since the division of labor was sexual, not vocational. The role of artistry in everyday life was more informal and ubiquitous. Everybody made things: tools, clothing, personal ornaments, shelters. Some individuals made things better than others. Making each object could serve as an occasion for demonstrating one's ornamental skills and aesthetic taste. Sometimes there was no time for such embellishments, but often there was.

For sexual choice to have favored good artistry, our ancestors needed only the opportunity to make sexual choices based on the extended phenotypes of potential mates, and the motive to pay attention to the extended phenotypes' aesthetic quality. It was not necessary for hominids to favor great artists over great hunters or great mothers. It was necessary only for them to favor those who showed taste and talent in their everyday self-ornamentation over those who did not, all else being equal.

Sexual Functions Versus Sexual Content

Prehistoric art had a lot of sexual content. Venus figurines are endowed with large breasts and buttocks. Rock-art often consists of nothing more than repeated motifs of female genitals. Ice Age Europeans carved phallic batons from bone and stone. One image from prehistoric Siberia appears to depict a man on skis attempting intercourse with an elk. This is all very interesting, but not very relevant to the sexual choice model for art's evolution.

Sexual selection for art need not imply that our ancestors favored hyper-sexual art in the style of Tantric Buddhism. They need not have gone around everywhere carving lingams (stylized phalluses) or yonis (stylized labia). Even if they did, that would reflect their interests without necessarily revealing the adaptive

benefits of their art. Some bowerbirds make bowers that are tall and conical like a phallus, and some make avenue-shaped bowers that look like yoni, but that is a meaningless coincidence irrelevant to their evolution through sexual selection. Tantric myth does provide some lovely metaphors for evolution through sexual selection. Creation occurred through sexual play between an Originating Couple. Krishna seduced all the cow-girls of Brindaban with his blue skin, beauty, and flute music. The path to enlightenment lies in joyful copulation as a mutual escalation of consciousness. Nevertheless, the fact that Pleistocene art often looks Tantric is not very relevant to the sexual choice theory

Darwinian Aesthetics

If we view art as an example of a biological signaling system, we can break it down into two complementary adaptations: capacities for producing art, and capacities for judging art. The second of these, our set of aesthetic preferences, seems more mysterious in some ways. If we assume a rich aesthetic sense to be part of human nature, we should not find it surprising that people figured out how to attract sexual partners and gain social status by producing things that others consider aesthetically pleasing. Neither, perhaps, should we find it surprising that sexually mature males have produced almost all of the publicly displayed art throughout human history Given any set of human preferences about anything, males have more motivation to play upon those preferences to attract sexual partners. It seems reasonable to posit that our capacities for producing art are legitimate biological adaptations that evolved over thousands of generations, rather than cultural inventions. But our aesthetic sense seems a good place to focus our analysis to see how far the sexual choice theory can go.

Why is beauty so compelling? Why do we find some things more beautiful than others? As far as our subjective experience goes, these are the central mysteries of art. It seems hard to connect our experience of beauty to any evolutionary theory of aesthetics. Yet with every one of our pleasures and pains there is this lack of an explicit link. A burning sensation does not carry an

intellectual message saying "By the way, this spinal reaction evolved to maximize the speed of withdrawing your extremities from local heat sources likely to cause permanent tissue damage injurious to your survival prospects." It just hurts, and the hand withdraws from the flame. Female sexual orgasm does not automatically create an intellectual appreciation of orgasm's role in promoting mate choice for good genes. No instinctive reaction to anything ever carries a special coded message saying why the reaction evolved. It doesn't have to—the reaction itself does the adaptive work of survival or reproduction.

Powerful reactions like aesthetic rapture are the footprint of powerful selection forces. Like our sexual preferences for certain faces and bodies, our aesthetic preferences may look capricious at first, but reveal a deeper logic on closer examination. If art evolved through sexual selection, our aesthetic preferences could be viewed as part of our mate choice system. They are not the same preferences we use to assess another individual's body, because, like most other animals, we already have rich sexual preferences about body form. Rather, they are the preferences we use in assessing someone's extended phenotype: the set of objects they made, acquired, and displayed around their bodies. To explain our aesthetic preferences, we should be able to use the same sexual selection theories that biologists use to explain mating preferences. As we saw in previous chapters, these boil down to three options: preferences that escalate through runaway effects, preferences that come from sensory biases, and preferences evolved to favor fitness indicators.

Runaway Beauty

Perhaps human aesthetics emerged through runaway sexual selection, with aesthetic tastes evolving as part of female mate choice. In this view, some female hominids just happened to have certain tastes concerning male ornaments. The artists best able to fulfill these tastes inseminated more aesthetic groupies and sired more offspring, who inherited both their artistic talent and their mothers' aesthetic tastes.

Something like this still happens among the Wodaabe people (also known as the Bororo), cattle-herding nomads who live in the deserts of Nigeria and Niger. At annual
geere wol
festivals, hundreds of people gather, and the young men spend hours painting their faces and ornamenting their bodies. The men also dance vigorously for seven full nights, showing off their health and endurance. Towards the end of the week-long ceremony, the men line up and display their beauty and charm to the young women. Each woman invites the man she finds most attractive for a sexual encounter. Wodaabe women usually prefer the tallest men with the whitest teeth, the largest eyes, the straightest nose, the most elaborate body-painting, and the most creative ornamentation. As a result, Wodaabe men have evolved to be significantly taller, white-toothed, larger-eyed, straighter-nosed, and better at self-decoration than men of neighboring tribes. This divergence probably happened within the last few hundred or few thousand years, illustrating runaway's speed. Journalists who know nothing of sexual selection often comment on the "reversal of sex roles" in Wodaabe beauty contests compared to European and American counterparts. But biologically, the Wodaabe are behaving perfectly normally, with males displaying and females choosing. The Miss America contests are the unusual ones.

As we saw with the runaway brain theory, runaway aesthetics would require polygamy and would result in large sex differences in artistic production. At first glance, it looks as if it should also produce large sex differences in aesthetic tastes, with females much more discriminating than males. If art were grown instead of made, that would be true. The peacock does not need the peahen's appreciation of a good tail—he needs only the tail itself. But for men to make good art, they must embody the same aesthetic discrimination as women. While decorating themselves, they must be able to access the same aesthetics that women will use in judging their decoration. Given this twist, the runaway aesthetic theory predicts sexual similarities in aesthetic taste, but much higher aesthetic output by males. That is roughly what we see in the history of art (although cultural and economic factors

may have amplified the sex differences in artistic output over the last few millennia).

Yet the runaway theory cannot account for anything about human aesthetics other than their existence. It can explain why we find some things more beautiful than others, but it cannot explain any of the aesthetic criteria we use to make such judgments, because any standard of beauty can evolve through runaway. Runaway sexual selection is arbitrary, so it does not offer a very satisfying theory of aesthetics. It might still be the right explanation, but perhaps we can do better.

Aesthetic Tastes as Sensory Biases

Sensory bias theory seems ideal for explaining our aesthetic preferences. Whenever we encounter a human taste for a certain kind of aesthetic stimulation by identifying the brain circuits involved in perceiving that stimulation, we could show that they are optimally stimulated by just that stimulation. Perhaps we like stripes because our primary visual cortex happens to be most sensitive to stripe-like patterns. Perhaps we like highly saturated primary colors because our photo-receptors are most highly activated by such hues. Every time we find any brain mechanism underlying an aesthetic preference, we could just declare it an intrinsic sensory bias, and stop the analysis there.

This is a surprisingly venerable strategy for understanding human aesthetics, dating back to Hermann von Helmholtz, Gustav Fechner, and the earliest experimental days of 19th-century neurophysiology. It became integrated into the first wave of evolutionary psychology in the 1870s through the 1890s, as in Grant Allen's books
Physiological Aesthetics
and
The Color Sense.
By 1908, Felix Clay's
The Origin of the Sense of Beauty
could review dozens of theories about the evolution of human aesthetics— mostly forgotten now, but at least as good as many modern ideas.

More recently, Nancy Aiken took this physiological approach in her 1998 book
The Biological Origins of Art
. She tried to identify brain mechanisms that would favor certain colors, forms, patterns, and symbols. But she did not analyze the evolutionary

costs and benefits of artistic behavior, or of having one set of aesthetic preferences rather than another. As we saw in the chapter on the ornamental mind, the sensory bias view is most useful when we can trace why our brain circuits evolved particular sensitivities. Sensory bias theorists do that by considering the relevant things that a particular species evolved to perceive under ancestral conditions. But physiological approaches like Aiken's do not usually take that next step of asking the evolutionary "why" questions. Why is our primary visual cortex most sensitive to stripes? Why does our color vision respond most strongly to highly saturated primary colors?

From an evolutionary viewpoint it is simply tautologous to say that humans have certain aesthetic preferences because our brains happen to have those aesthetic preferences. From a neuroscientist's viewpoint, we are our brains. It should come as no surprise that every one of our preferences is implemented somehow, somewhere in the brain. This is equally true of genetically evolved preferences and culturally acquired preferences. The identification of a brain mechanism may look as if it is providing evidence of an evolved adaptation, but it is not. Any culturally acquired behavior will be manifest in some brain mechanism too. Of course we will find neurochemicals and hormones and neural pathways that correspond to strong aesthetic emotions. So?

Sensory bias theory becomes more interesting when it is possible to show that the sensory bias evolved long before the relevant sexual ornamentation. For human aesthetic preferences, this would mean finding evidence for the preferences in other primates. So far most attempts to do that have failed. In the 1970s, Nicholas Humphrey tried very hard to find evidence of visual aesthetic preferences in rhesus monkeys. They preferred white light to red light, focused pictures to out-of-focus pictures, and pictures of monkeys to pictures of anything else. But they showed no sign of any aesthetic preferences for forms, patterns, symmetries, or compositions. Rhesus monkey visual systems are so similar to ours that they are often used by neuroscientists as experimental models for human vision. Yet they show no hint of

the aesthetic preferences that we might expect as side-effects of having our sort of vision.

Other evidence against the sensory bias view comes from experiments on painting by chimpanzees. Desmond Morris's 1962 book
The Biology of Art
showed that, given paper, brushes, and paint, chimpanzees produced works resembling the abstract expressionist paintings that were in vogue at the time. Morris had been searching for evolutionary continuity between ape and human aesthetics, and thought he had found some evidence for a sense of pictorial composition and balance in apes. In appreciation of Morris's research, Salvador Dali declared that "The hand of the chimpanzee is quasi-human, the hand of Jackson Pollock is almost animal." However, later research suggested that chimps do not produce artworks according to a goal-oriented plan. They paint reactively in relation to the paper's edges and to any geometric forms already printed on the paper. If a human does not snatch away the paper in time, the chimp tends to cover it in a meaningless multicolored smear. Given paints and brushes in a more natural setting, chimps do not seek out a flat rectangular surface to make a picture—they just playfully paint the nearest bush or rock. Apes show few aesthetic preferences when given images, and show little patience for producing aesthetically structured images when given artistic materials. We should not expect to find any evidence in apes of human adaptations that probably evolved within the last million years, because our most recent common ancestor lived at least five million years ago.