The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature (58 page)

So, when women universally complain about their slothfully mute boyfriends, we learn two things. First, women have a universal desire to enjoy receiving high levels of verbal courtship effort. Second, high levels of verbal courtship effort are so costly that men have evolved to produce them only when they are necessary for initiating or reviving sexual relationships. Far from undermining the courtship hypothesis for language evolution, this phenomenon provides two key pieces of evidence that support it.

The Scheherazade Strategy

Because verbal courtship is mutual, we might expect men to feel equally frustrated by women lapsing into habitual silence as a relationship ages. This seems less often lamented, either because men develop less hunger for conversation, or because women maintain their verbal courtship effort at a higher pitch for longer.

Earlier we saw that male mate choice grows stronger later in

courtship, as men may be tempted to abandon a woman after she has become pregnant, and search for a new woman. In the Pleistocene age, females who could keep a useful male around for longer would have enjoyed more comfortable lives, and their children would have prospered. Through their courtship efforts, ancestral females could maintain male sexual commitment and paternal investment in their offspring. Sexual selection through male mate choice created modern women's drive to keep men sexually attracted to them over the long term. They do this, in part, by continuing to use verbal courtship long after men might prefer to read the newspaper.

The female incentives for sustained verbal courtship are illustrated by the classic Arabian folk tale of a thousand and one nights. The story goes like this. Shahriyar was a powerful Sassanid king who discovered his wife having sex with a slave. Mad with rage, he killed them both. To avoid further problems of female infidelity, he swore to sleep with a new virgin every night and to kill her in the morning. That way, no other man would have slept with her before him, and no other man could sleep with her after him. He did this for three years, until few young women were left in the city, except for the Grand Vizier's two daughters, Scheherazade and Dunyazad.

Scheherazade swore to save the women of the city from further danger, and offered herself next to Shahriyar. After Shahriyar deflowered her, Scheherazade begged him to let her say goodbye to her sister Dunyazad. Dunyazad, as previously arranged, asked Scheherazade to invent a story to help them pass their last night together in sisterly solidarity. The sultan, overcome with insomnia, agreed to hear her out. Scheherazade began a story that grew so complex and entertaining that she had still not finished it when dawn broke. Shahriyar was so enthralled by the story that he could not bear to kill the storyteller, so he agreed to spare Scheherazade 's life for one more day. The next night, the same thing happened: Scheherazade wove one story into the next, and was in the middle of a complicated plot as dawn broke. Again Shahriyar agreed to spare her life for one more day. This pattern

continued for many months of storytelling and lovemaking.

After a thousand and one nights, Scheherazade had borne Shahriyar three sons, and she begged the king to allow her sons to be brought before him. Displaying the boys—a toddler, an infant, and a newborn—she asked for their sake to spare her life, observing that no other woman would love his sons as she would. The king embraced his sons and exclaimed that even before their arrival, he had fallen in love with Scheherazade for her creativity, eloquence, intelligence, wisdom, and beauty. The next morning he publicly spared Scheherazade's life, and they lived happily together until death delivered them both to Paradise.

This story presents an uncannily accurate picture of the male mate choice pressures on ancestral human females, and the solution they apparently evolved. Shahriyar's fear of being cuckolded reflects what biologists call "paternity uncertainty": the male never knows for sure whether a female is being sexually faithful, and therefore whether his alleged children actually carry his genes. To guard against this paternity uncertainty, Shahriyar adopted an absurdly short-term mating strategy. By bedding a virgin every night, he knew she was not already pregnant with another man's child; by killing her the next morning, he knew that she would not be unfaithful in the future. This proved to be counterproductive: no heirs were produced to carry his selfish genes, and he had killed off most of the fertile women.

The pressures on Scheherazade were intense. Given a sexually jaded despot obsessed with his paternity uncertainty and caught in a pathologically short-term mating strategy, how could she elicit his long-term investment in herself and her offspring? Her verbal courtship ability proved her salvation. She invented stories that kept him entertained, and which persuaded him of her intelligence, creativity, and fitness. The thousand and one nights constitute a massive, long-term verbal courtship display. Shahriyar realized that Scheherazade's mind was an oasis of narrative fascination in his desert of sexual novelty-seeking. She made monogamy fun. She also made it pay genetically for both of them: Shahriyar's genes prospered jointly with Scheherazade's.

Evolution has extended human verbal display from the early stages of courtship through the entirety of sexual relationships. Talking keeps relationships interesting. Women use the Scheherazade strategy, but so do men. Long after partners grow overfamiliar with each other's bodies, the Scheherazade strategy—trying to keep conversations interesting throughout a relationship—keeps them from growing bored with each other's company. This probably brought mutual benefits to our ancestors. It allowed our female ancestors to keep useful males around, and it may have helped those males to overcome their sexual novelty-seeking when it became counterproductive.

As brain size increased over the last two million years, infants had to be born relatively earlier in their development so their heads could fit through the birth canal. All human babies are born prematurely relative to other primate babies. Human babies are less competent and more vulnerable at birth than almost any other mammal. This may have tipped the balance for men, making assistance to their own offspring more beneficial to their genes than seeking new mates. The sexual novelty-seeking characteristic of all male mammals was an ancient instinct, not easy to overcome. By evolving an appreciation of the cognitive novelties offered by good conversation with an established partner, men may have muted their obsession with the physical novelties of other women. This is why Shahriyar learned to listen, once Scheherazade started talking.

Language Outside Courtship

Human language did not evolve just for courtship, so that we could all talk like Cyrano and Scheherazade. It was shaped by many other selection pressures: for communication between relatives, social display to non-mates, coordination of group activities, and teaching things to children. Even if it originated as pure verbal courtship, like bird song, without any survival payoffs at all, it would soon have proved its other virtues. As Terence Deacon and others have observed, it is hard to imagine any social activity that would not benefit from language. The frustrations of visiting

places where people speak foreign languages reveal the survival and social benefits of effective communication.

But a frustration is not the same as a selection pressure. We must remember that any theory of language's other social benefits

must explain its apparent altruism with some hidden genetic

benefit. If those hidden benefits turn out to be sexual, then we are back where we started. Much of the effort invested in apparently

non-sexual uses of language may work as indirect courtship.

Social display to non-sexual partners can improve one's mating prospects. Opposite-sex friends may become lovers, same-sex

friends may have eligible sisters or brothers, and high-status tribe members impressed with your charms may gossip about you to others. Having a good reputation gives one a huge advantage before courting someone, and the two things that contribute to a good reputation are good words and good actions.

Language is useful in coordinating group activities, but here again we have an altruism problem. In the chapter on morality we

saw that group benefits like big-game hunting and moral leadership could be favored by sexual selection. If an individual's ability to improve group success through verbal leadership is judged by potential mates, then apparently cooperative uses of language may conceal courtship functions.

Even when non-sexual pressures started to shape human language, sexual selection would have subverted those pressures.

This is because sexual choice tries to preempt the effects of natural

selection as much as possible. For example, consider language as a way to teach children about plants and animals. Survival

selection might favor such pedagogy—one's children would

be less likely to die of poisons and bites. Yet individuals might vary in teaching ability. If their differences remain

genetically heritable (as they probably would, given the pressures of mutation on complex traits), and if teaching ability was reasonably important, sexual preferences would evolve to favor that ability. Individuals who mated with good teachers would produce children who taught their grandchildren more efficiently, allowing more grandchildren to carry one's genes forward. The ancestral versions of

David Attenborough would have been perceived as sexually charismatic, not just as good parents. At that point, teaching ability would have been favored by both survival selection and sexual selection.

Fact and Fantasy

Scheherazade attracted her sultan with fantasies. If sexual choice shaped language as an entertaining ornament and a fitness indicator, why does language have any factual content at all? Other sexually selected signals such as the songs of birds and whales do not say anything other than "I am fit—mate with me." We saw earlier that life stories, social gossip, and large vocabularies can work as good fitness indicators. They all demand content. But they do not seem to demand enough factual content to explain our interest in the truth, or the efficiency of language as a communication medium.

I think that, as with human morality, there was an equilibrium selection process at work. Every possible sexual signaling system can be viewed as an equilibrium in the grand game of courtship. There are more than a million sexually reproducing species on Earth, each with their own sexual signals. That means there are more than a million possible equilibria in the courtship game. At each equilibrium, individuals are displaying the best signals they can, and choosing the best mates they can, and nobody has any incentives to deviate from what they are already doing. In the vast majority of equilibria—(i.e. species)—apparently more than 99.9 percent of them—sexual signals convey no information other than fitness information. They are pure fitness indicators. Human language is the only signaling system that conveys any other sort of information in courtship. It is still a fitness indicator, but it is much more as well.

The Scheherazade problem is this: there could be "fantasy" equilibria where people impress mates by making up stories about fictional worlds, and "fact" equilibria where people impress mates by displaying real knowledge of the real world. As long as both displays are good fitness indicators, sexual selection should not

favor fact over fantasy. Was it just blind luck that we ended up on a relatively factual equilibrium, where people care about truth and knowledge?

Imagine a fantasy equilibrium where verbal courtship display consists exclusively of spinning wild stories about battles waged with magic spells between wizards from alien civilizations. Individuals talk about nothing else. If the ability to invent wizard stories was a good fitness indicator, sexual selection would be perfectly happy with this equilibrium. The pointless waste of breath talking about wizards would not worry sexual selection any more than the peacock's tail does.

The trouble with a purely fantasy equilibrium is that the individuals would literally not know what they are talking about. How would they learn what any of their words mean? Their words refer only to fictional magic spells from alien civilizations. Their parents could not take them a hundred light-years away, point to a magic spell that creates a lethal hail of neutron stars, and say, "Look, that's a xoplix!" Words must be grounded in the real world in order to have any meaning. Humpback whale songs might accidentally be referring to actual events on alien worlds, but we wouldn't know, and neither would they. No animal playing a purely fantasy equilibrium could tell it from an ordinary fitness-indicator equilibrium.

The only way a signal can activate a concept in another individual's head is for the signal to be grounded, directly or indirectly, in some real-world meaning. This excludes all purely fantasy equilibria. Scheherazade's stories recombined real-world ideas in fantastic ways. She did not refer exclusively to fictional ideas. I suspect that there are only two kinds of sexual-signaling equilibria that are evolutionarily stable, in any naturally evolved species anywhere in the universe: pure fitness indicators, and language systems that make reference to objects and events in an organism's perceivable environment.

Scheherazade Versus Science

Language must be grounded in reality, but how tightly grounded? Sexual selection still has elbow room to favor Scheherazade equilibria (fantastic stories based on recognizable objects) or science equilibria (useful, true descriptions of the world). Now I am no longer sure which equilibrium our species is playing. Most people in most cultures throughout most of history have talked reasonably accurately about ordinary objects, people, and events, but they have talked absolute fantasy about astronomy, cosmology, theology, and any other phenomena that could not be directly observed.