The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature (27 page)

top/bottom asymmetry that gives wings lift. Some have even proposed that feathers originated for insulation, feathered wings helping females to incubate their eggs, as in ostriches. But perhaps wings originated as sexual ornaments, along the following lines. Take a fairly useless dinosaur forelimb. Add a bit of color or an extra skin-flap with a novel mutation. Apply sexual choice and the runaway process. Result: a large surface area ornamented with color, available for display to the opposite sex. Feathers make excellent sexual ornaments—they are light, flexible, and movable. They are still used in courtship displays by male rifle-birds, who snap them open and shut in front of awestruck females. If the male protobirds happened to combine their forelimb displays with energetic jumps during courtship, and if females selected for the best jumpers, then the transition from a display function to an aerodynamic function would be relatively smooth. Once wings proved useful in other contexts such as escaping predators, then survival selection

would start shaping them for flight instead of just sexual ornamentation. This would have led to the well-documented

proliferation of bird species well before the extinction of their dinosaur cousins 65 million years ago, and continuing to the

present.

Of course, this scenario for wing evolution is just one hypothesis, and it is by no means clear whether it is right. At least this speculative example illustrates the general point that courtship innovations can potentially lead to unanticipated survival advantages. If we want to overcome the threshold problem of how evolution can favor the initial stages of innovations before they show net survival benefits, sexual selection seems to be a very strong candidate.

The human mind can be seen as one of these courtship innovations that happened to show some large survival advantages long after it first evolved. Modern
Homo sapiens
evolved about 100,000

years ago in Africa. By that time, our ancestors had brains the same size as ours. Yet almost all of the technological process in toolmaking came tens of thousands of years later. Agriculture took another 90,000 years to invent, and only after that did the global

human population climb above a few million. More than 95,000 years after human language probably evolved, we invented writing and reading, allowing useful information to be transmitted down through generations and across great distances.

Neanderthals had already evolved quite large brains 200,000 years ago, yet showed very limited technological progress and very modest abilities to spread into new habitats. Neanderthals may have had most of the courtship innovations that we call the human mind, yet they did not stumble upon the potential survival advantages conferred by our sort of creative intelligence. Our lineage did, so we imagine those survival advantages as projecting all the way back to the mind's origins.

Every inventor knows that innovation depends a lot on serendipity. A novelty may be invented for one purpose, only to prove its value years later for a completely different purpose. The Chinese invented gunpowder for firework displays, and the Europeans adopted it for warfare. The dinosaurs may have evolved proto-wings as sexual ornaments, and evolved into birds that use them for flight. The human mind may have evolved as a set of fitness indicators and sexual ornaments, and now we use it to make movies, give venture capital to start-up companies, and read books on mental evolution. Each species is free to use its sexually selected adaptations for any non-sexual purpose that it can invent—and as long as that purpose contributes somehow to survival or reproduction, selection can favor such use.

Sexual selection thus works as a natural source of serendipity in evolution. It gives evolution the slack it needs to play around without demanding that every cost incurred now must yield some future economic benefit. As all scientists know and most governments forget, this is the only way that productive research and development happens.

From a Production Orientation to
a Marketing Orientation

oriented corporation. Until the 1950s, corporate management usually focused on making production more efficient. The goal was to transform raw materials into physical products as cheaply and reliably as possible. Henry Ford's production line was the icon of good management, even though it made Model-T cars in only one color. Advertising was an afterthought—just a way to get rid of the product once the hard job of making it had been accomplished. This is how many biologists still view evolution. Natural selection does the hard work of creating efficient organisms that transform food into growth, and into more organisms. Sexual selection does a little advertising as an afterthought, once the product—the organism—is available for purchase in the sexual marketplace.

Then, in the 1950s and 1960s, a revolution swept through the business world. Beginning with innovative consumer-oriented companies like Procter & Gamble, the "marketing orientation" took over from the old "production orientation." According to the marketing orientation, a company's goal should not be to manufacture physical objects, but to make profits by fulfilling consumers' needs, wants, and preferences. Production matters only insofar as it contributes to consumer satisfaction. If nobody wants a product, there is no point in making it. If everybody wants something different from what is being made, a company would do better to change what it makes.

The marketing-oriented company works backwards from consumer preferences, not forwards from raw materials. Advertising is not some mysterious luxury hovering above the factory, but the only way to connect consumer preferences to the products on offer, and hence to profits. Indeed, advertising and packaging becomes a major part of the product. A marketing orientation does not just mean more sophisticated advertising. It means reshaping everything a company does so that it contributes to satisfying some consumer preference in a profitable way. (This may, of course, include crafting a culturally learned preference out of the human instincts for acquiring status, displaying wealth, and attracting mates.) The marketing revolution was probably the most significant change in business thinking since the invention of

money. It puts consumer psychology at the heart of practical economics. It is responsible for the dazzling proliferation of products and services in modern economies. Not all corporations have shifted from the production to the marketing orientation, but the most successful ones have.

By suggesting that sexual selection plays a major but neglected role in evolutionary innovation in general and the human mind's

evolution in particular, I am proposing a sort of marketing

revolution in biology. Survival is like production, and courtship is
like marketing. Organisms are like products, and the sexual

preferences of the opposite sex are like consumer preferences.

Courtship displays are not a mysterious luxury soaking up excess
energy after the business of survival is accomplished. Rather, they

are the only way to get one's genes into the next generation, by fulfilling the sexual preferences of the opposite sex. Survival matters only insofar as it contributes to courtship. If nobody wants to mate with an animal, there is no evolutionary point in the animal surviving.

A marketing orientation does not imply shoddy production. On the contrary, greater sensitivity to consumer demands for

high-quality products may force companies to improve

production standards. Likewise, mate choice for fitness
indicators may drive very fast improvements in fitness. Through

fitness indicators, sexual selection preserves the near-perfection of biological adaptations, and protects them against erosion by mutations.

A marketing orientation may result in a seemingly irrational diversification of products and species. Procter & Gamble filled

supermarket shelves with dozens of nearly identical detergents

and soaps, each aimed at a different market niche. This may seem
wasteful, but evolution does the same thing. It fills ecosystems with

dozens of nearly identical species, each with slightly different courtship behaviors and displays. This is how sexual selection splits species apart. It may explain the biodiversity of sexually reproducing animals and flowering plants.

Most importantly, a marketing orientation does not imply that advertising crowds out innovation. Quite the opposite: the

market's hunger for novelty drives greater investment in research and development, and the efficiency of advertising makes corporations confident that the benefits of innovations will exceed their research costs. Sometimes, by trying to find a superficial variant that attracts consumer attention, a company will stumble upon a major invention that becomes the industry standard after a few years. Likewise, sexual selection rewards the novel and the ornamental, but this does not rule out the useful. A courtship innovation may later prove its worth as a survival advantage.

A marketing orientation in evolution does not just mean paying a little more attention to courtship as a form of advertising. It means that every aspect of an organism's growth, structure, and behavior has been shaped to fulfill the sexual preferences of the opposite sex. It puts courtship at the heart of modern biology, as marketing is at the heart of modern business. This marketing revolution swept through the organic world half a billion years ago, just after the Cambrian explosion produced the first complex, sexually reproducing animals. Any animal that persisted in a production orientation, an obsession with food and survival, lost out to competitors that adopted a marketing orientation, an obsession with profiting genetically by pleasing the opposite sex. The explosion of organic complexity and diversity in the last half billion years is just what we would expect if evolution underwent a marketing revolution.

Animal minds are not uniformly black Model-T cars churned out by the assembly line of natural selection. They are self-advertising, self-promoting, self-packaging products adapted from the bottom up, from the inside out, from birth to death, to the

demands of their consumers: the opposite sex. In modern society, we may feel ambivalence about the marketing orientation of the

businesses that shape our lives. Their marketing departments take

an interest in our attitudes that is both flattering and alarming. But it would be hypocritical to pretend that we are in this marketing

world but not of it. I believe that our minds evolved through a million years of market research called sexual selection. From this perspective, we are walking, talking advertisements for our genes.

This marketing perspective has implications not only for evolutionary biology, but also for evolutionary psychology. If species evolve to adopt this marketing orientation dictated by sexual selection, then perhaps natural selection's status in evolution has been overestimated. If mate choice promotes speciation and innovation, then sexual selection may be to macro-evolution what genetic mutation is to micro-evolution: the prime source of potentially adaptive variation, at both the individual level and the species level. Like mutations, most courtship innovations could be viewed as costly wastes. But, also like mutations, a few courtship innovations like the human brain may prove spectacularly useful.

It may be no accident that sexual life forms dominate our planet. True, bacteria account for the largest number of individuals, and the greatest biomass. But by any reasonable measures of species diversity, or individual complexity, size, or intelligence, sexual species are paramount. And of the life forms that reproduce sexually, the ones whose reproduction is mediated by mate choice show the greatest biodiversity and the greatest complexity. Out of the million or so known animal species, the vast majority reproduce sexually, including the majority of insects. Almost all animals larger than a couple of millimeters are sexual reproducers capable of sexual choice: all mammals, all birds, all reptiles. The situation is similar with plants. Of some 300,000 known plant species, about 250,000 reproduce through flowers that attract pollinators. Without sexual selection, evolution seems limited to the very small, the transient, the parasitic, the bacterial, and the brainless. For this reason, I think that sexual selection may be evolution's most creative force. It combines an inventor's playful love of discovery with the venture capitalist's willingness to invest enough in innovations to bring them to the market where they may prove useful. We shall see next how the mating market may have operated among our ancestors, and how courtship and mate choice may have generated the evolutionary innovations that constitute human nature.

6

Courtship in the

Pleistocene

To judge a new theory of human evolution, it can be more important to forget one's preconceptions than to learn a set of new facts and ideas. Most of our images of human evolution come from popular culture. Film, television, cartoons, and advertising have filled our heads with a lot of colorful nonsense about prehistory. If the image in your mind is of cave-men clubbing cave-women unconscious and dragging them off, you may not grant sexual choice much significance in human evolution. This chapter aims to confront these preconceptions, inquiring how our ancestors did and did not form sexual relationships.

Popular culture images of prehistory are divided by market segmentation according to consumer age group, and by sexual