The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature (63 page)

Theories of human evolution are scientific hypotheses, but they are also stories. To develop a good new hypothesis, it can help to choose a story from an overlooked genre. The traditional evolution stories could be filmed largely as action adventures, war stories, or political intrigues. In casting one would automatically visualize Mel Gibson in a fur loincloth with a steely gaze, glistening pectorals, and hearty clansmen, battling for independence from Neanderthal oppressors. Or Sigourney Weaver fighting Pleistocene monsters in dark tunnels to protect endangered children, after her less intelligent male comrades have been disemboweled.

I am making a different pitch, for romantic comedy as the genre least likely to mislead us, if we think of human evolution as a narrative. My rationale is that in action, war, and intrigue, people mostly just die. But in romantic comedy, people sometimes get pregnant. Evolution is a multi-generation epic that depends on some couples courting and having children. Although action adventures better fulfill Aristotle's insistence on the dramatic unities of time and place, maybe we should pay more attention to Darwin's insistence on our unbroken chain of descent. Human evolution could be imagined as a million-year-long version of
Bringing Up Baby
, in which ancestral Katharine Hepburns and Cary Grants fell in love through a combination of slapstick, verbal repartee, and

amusing adventures with wild animals. Evolution may be heartless, but it is not humorless.

Sexual Personae

By viewing human evolution as a romantic comedy, we might understand not only our creative capacities for producing witty novelties, but also our ability to reinvent ourselves with each new sexual relationship. People act differently when they're in love with different people. We tend to match our expressed interests and preferences to those of a desired individual. One develops a crush on a mountain-climber, and suddenly feels drawn to the sublime solitude of the Alps. One dates a jazz musician, and feels prone to sell one's now puerile-seeming heavy metal albums. Should an otherwise perfect lover confide her secret belief in the healing power of crystals, one may find yesterday's sneering skepticism about such nonsense replaced by a sudden open-mindedness, a certain generosity of faith that must have lain dormant all these years. In courtship, we work our way into roles that we think will prove attractive.

Chimpanzees have some capacities for "tactical deception," for pretending to do something other than what they are really doing. But they cannot pretend to be someone other than who they are. Sexual courtship may have been the arena in which we evolved the capacity for dramatic role-playing. With each new lover, we experience a shift in image and identity. These shifts are rarely as dramatic as the changes of sexual personae adopted by David Bowie or Madonna with each new album. But they are more profound. Often, we may find it difficult to relate to our former selves from previous romances. Events experienced by that former self, which seemed so vivid at the time, become locked away in a separate quadrant of memory's labyrinth, accessible only if we happen to run into the former lover. Our minds undergo these sexual revolutions, reshaping themselves to each new lover like an advertising company dreaming up new campaigns for capturing new market niches.

Acting is not the prerogative of a few highly strung

professionals, but a human birthright, automatically activated whenever we fall in love. In courtship, all the world became a stage, and all the proto-humans merely players. Perhaps we evolved the ability to creatively role-play because sexual choice favored those who were better at adopting an attractive series of sexual personae. Our identity shifts operate not only at the level of consciousness and identity, but at all observable levels: ornamentation, clothing, posture, gesture, accent, facial expression, attitude, opinion, and ideology

Creative Ideologies Versus Reliable Knowledge

Sexual selection for creativity raises some worries about the reliability of human knowledge. According to traditional views, animals with delusions should be eliminated by natural selection. Evolution should produce species with brains that interpret the world more and more accurately, enabling behavior to be guided more adaptively. Such reasoning is central to the field of "evolutionary epistemology," which studies how evolutionary processes can generate reliable knowledge. Evolutionary epistemologists such as Karl Popper, Donald Campbell, and John Ziman have credited evolution with a tendency to endow animals with reasonably accurate models of the world. This idea seems to solve many of the traditional philosophical worries about the validity of human perception and belief.

For most kinds of knowledge embodied in most of our psychological adaptations, I think that their argument is correct. Natural selection has endowed us with an intuitive physics that allows us to understand mass, momentum, and movement well enough to deal with the material world. We also have an intuitive biology that allows us to understand plants and animals well enough to survive, and an intuitive psychology that lets us understand people. Especially since the 1980s, psychologists have been busy investigating these intuitive forms of knowledge in children and adults. Our hundreds of adaptations for sensation, perception, categorization, inference, and behavior embody thousands of important truths about the world.

However, when we come to verbally expressed beliefs, sexual selection undermines these reliability arguments. While natural selection for survival may have endowed us with pragmatically accurate perceptual systems, mate choice may not have cared about the accuracy of our more complex belief systems. Sexual selection could have favored ideologies that were entertaining, exaggerated, exciting, dramatic, pleasant, comforting, narratively coherent, aesthetically balanced, wittily comic, or nobly tragic. It could have shaped our minds to be amusing and attractive, but deeply fallible. As long as our ideologies do not undermine our more pragmatic adaptations, their epistemological frailty does not matter to evolution.

Imagine some young hominids huddling around a Pleistocene campfire, enjoying their newly evolved language ability. Two males get into an argument about the nature of the world, and start holding forth, displaying their ideologies.

The hominid named Carl proposes: "We are mortal, fallible primates who survive on this fickle savanna only because we cluster in these jealousy-ridden groups. Everywhere we have ever traveled is just a tiny, random corner of a vast continent on an unimaginably huge sphere spinning in a vacuum. The sphere has traveled billions and billions of times around a flaming ball of gas, which will eventually blow up to incinerate our empty, fossilized skulls. I have discovered several compelling lines of evidence in support of these hypotheses. .. ."

The hominid named Candide interrupts: "No, I believe we are immortal spirits gifted with these beautiful bodies because the great god Wug chose us as his favorite creatures. Wug blessed us with this fertile paradise that provides just enough challenges to keep things interesting. Behind the moon, mystic nightingales sing our praises, some of us more than others. Above the azure dome of the sky the smiling sun warms our hearts. After we grow old and enjoy the babbling of our grandchildren, Wug will lift us from these bodies to join our friends to eat roasted gazelle and dance eternally. I know these things because Wug picked me to receive this special wisdom in a dream last night."

Which ideology do you suppose would prove more sexually attractive? Will Carl's truth-seeking genes—which may discover some rather ugly truths—out-compete Candide's wonderful-story genes? The evidence of human history suggests that our ancestors were more like Candide than Carl. Most modern humans are naturally Candides. It usually takes years of watching BBC or PBS science documentaries to become as objective as Carl.

Runaway sexual selection for ideological entertainment would not have produced accurate belief-systems, except by accident. If ideological displays were favored as fitness indicators, the only truth they had to convey was truth about fitness. They need not be accurate world-models any more than the eyes of a peacock's tail need to represent real eyes.
Das Kapital
demonstrated Karl Marx's intelligence, imagination, and energy, but its reliability as a fitness indicator does not guarantee the truth of dialectical materialism. The majesty of Brigham Young's religious visions were sufficient to attract 27 wives (who averaged 24.5 years old at marriage— with wives number 12 through 21 marrying him when he was in his mid-40s), but that does not guarantee the veracity of his belief that dead ancestors can be retroactively converted to the Mormon faith.

When we considered the evolution of language, we saw that sexual selection rarely favors displays that include accurate conceptual representations of the world. Across millions of species throughout the Earth's history, there have been only two good examples of sexual selection for world-representing truth: human language and human representational art. Even so, human language's ability to refer to real objects and events does not guarantee the reliability of human ideologies expressed through language.

Sexual selection usually behaves like an insanely greedy tabloid newspaper editor who deletes all news and leaves only advertisements. In human evolution, it is as if the editor suddenly recognized a niche market for news in a few big-brained readers. She told all her reporters she wanted wall-to-wall news, but she never bothered to set up a fact-checking department. Human

ideology is the result: a tabloid concoction of religious conviction, political idealism, urban myth, tribal myth, wishful thinking, memorable anecdote, and pseudo-science.

Richard Dawkins has suggested that these ideological phenomena all result from "memes"—virus-like ideas that evolved at the cultural level to propagate themselves by grabbing our attention, remaining memorable, and being easy to transmit to others. The meme idea offers a novel perspective on human culture, but it begs several questions. Why do people display such ideas so fervently in young adulthood, especially during courtship? Why do people compete to invent new memes that will make them famous? Why were most memes invented by men? Why did natural selection leave us so vulnerable to ideological nonsense? Perhaps by viewing ideological displays as part of courtship, we can answer such questions. Mostly, we use our memes to improve our sexual and social status; they do not just use us.

This sexual selection theory of ideology poses a serious challenge to evolutionary epistemology. Natural selection can favor accurate intuitive models of the world, but it seems incapable of producing communication systems that allow those models to be shared. Sexual selection can favor rich communication systems such as language, but it tends to distort verbally expressible world-models, making them more entertaining than accurate. There seems to be a trade-off between reliable individual cognition and social communication—we can be mute realists or chatty fabulists, but not both. This is far from the evolutionary epistemology view, in which truth-seeking cognition evolved with truth-sharing language to give us a double-barreled defense against falsehood.

Our ideologies are a thin layer of marzipan on the fruitcake of the mind. Most of our mental adaptations that patiently guide our behavior remain intuitively accurate. They are our humble servants, toiling away at ground level, unaffected by the strange signals and mixed metaphors flying overhead from one consciousness to another during the mental fireworks show of courtship. Sexual selection has not impaired our depth perception, voice

recognition, sense of balance, or ability to throw rocks accurately But it may have profoundly undermined the reliability of our conscious beliefs. This is the level of epistemology that people care about when they challenge other people's claims to "knowledge" in the domains of religion, politics, medicine, psychotherapy, social policy, the humanities, and the philosophy of science. It is in these domains that sexual selection undermines the evolutionary epistemology argument, by turning our cognitive faculties into ornamental fitness-advertisements rather than disciples of truth.

Creative Science

Given minds shaped by sexual selection for ideological entertainment rather than epistemic accuracy, what hope do we have of discovering truths about the world? History suggests that we had very little hope until the social institutions of science arose. Before science, there was no apparent cumulative progress in the accuracy of human belief systems. After science, everything changed.

From a sexual selection perspective, science is a set of social institutions for channeling our sexually selected instincts for ideological display in certain directions according to strict rules. These rules award social status to individuals for proposing good theories and gathering good data, not for physical attractiveness, health, kindness, or other fitness indicators. Scientists learn to derogate the normal human forms of ideological display: armchair speculation, entertaining narratives, comforting ideas, and memorable anecdotes. (Of course, this spills over into derogation of popular science books that try to present serious ideas in attractive form.) Science separates the arenas of intellectual display (conferences, classrooms, journals) from other styles of courtship display (art, music, drama, comedy, sports, charity). Science writing is standardized to channel creativity into inventing new ideas and arguments instead of witty phrases and colorful metaphors. Scientists are required to provide intellectual displays to young single people (through undergraduate teaching,