Quotes from Geoffrey Miller

Human vocabulary size may have evolved through the same sexual selection process that favored enormous song repertoires in some bird species. But whereas only male birds sing, both men and women use large vocabularies during courtship, because courtship and choice are mutual, and because unusual words work as reliable displays only if their meanings are understood.

Through memory and language, we can transform a pure fitness cost in the past (such as a physical wound or a social rejection) into a reliable fitness indicator in the present (a story about our ability to heal without disability, or to overcome depression).

The common denominator in business marketing, political democracy, and religious reform is the transfer of power from service providers to service consumers.

Language lets us learn about potential mates much more efficiently and interactively than any other species can.

Verbal courtship continues for months after people first meet, and it becomes the bedrock of human intimacy and love.

Other primate penises are pencil-thin, whereas the erect human penis averages over one inch in diameter. Also, most other primates have a penis bone called the baculum, and achieve erections mostly through muscular control, like a winch raising a rigid strut. The penis bone is typical of most mammals. By contrast, the male human relies on an unusual system of vasocongestion. The penis fills with blood before copulation, like a blimp inflating before flight.

Among primates, the intensity of sperm competition correlates much more strongly with testicle size than with penis size.

Female adolescents are significantly less fertile than 20-year-olds. Female fertility declines gradually during the thirties, and declines steeply after age 40. Women after menopause are infertile. This female fertility profile is a basic fact of life to which male mate choice systems have adapted. Youth is an important cue of fertility.

He theorized that these sex differences (dimorphisms) were due to females being choosier about their mates and males competing more intensely for mates. We now know that Darwin was correct. When mate choice occurs, females typically do the choosing.

Males, for example, may compete directly to copulate with fertile females or compete indirectly for food, territory, nest sites, or social status that may increase their access to fertile females. In either situation, females are not exactly "choosing" from among male competitors, but acquiescing to sex with the male that holds the food, territory, or nest site that they need in order to reproduce.

Single mothers may have been the norm during most of human evolution, as they were during the previous 50 million years of primate evolution.

In almost all mammals and all primates, females do almost all of the child care, with very little help from males. Males could never be sure which offspring really carried their genes, whereas females could be certain. This uncertainty about paternity leads most male mammals to invest much more in pursuing new sexual opportunities than in taking care of their putative offspring.

There is strong evidence from evolutionary psychology that men in modern societies generally prefer the physical appearance of women around 20 years old to those who are older (or younger).

As in other species, male humans participate much more often in competitive sports than females. But every human culture invents different sports. We inherit the physical capacities and motivations to learn sports, not the specific genes for football, skiing, or boxing.

Males of all mammalian species risk their lives in ritualized sexual competition. We humans have invented thousands more ways of doing so, using our unique mental capacities to understand and follow the rules of sporting competition.

Under natural selection, species adapt to their environments. When the environment refers to a species' physical habitat, this seems simple enough. If a species lives in the Arctic, it had better evolve some warm fur. Under sexual selection, species adapt too, but they adapt to themselves. Females adapt to males, and males adapt to females. Sexual preferences adapt to the sexual ornaments avaliable, and sexual ornaments adapt to sexual preferences.

Sexual selection for the human body was not restricted to sexual ornaments. Once the capacity for sports evolved, sexual choice could favor fit bodies over unfit bodies much more directly.

The discriminatory nature of sexual choice undermines all egalitarian Utopias. Women might like the idea of all men being able to have equal amounts of sex, but no individual woman would be willing to forgo her power of sexual choice to allow an unattractive, unfit man to copulate with her.

Human courtship, like courtship in other animals, has a typical time-course. Courtship effort is low when first assessing a sexual prospect, increases rapidly if the prospect reciprocates one's interest, peaks when the prospect is deciding whether to copulate, and declines once a long-term relationship is established.

Milk-substitute manufacturers have worked very hard for almost a century to convince women that they are not mammals and have no business breast-feeding.

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.

Female orgasm seems poorly designed as a pair-bonding mechanism, but it is perfectly designed as a discriminatory system that separates the men from the boys.

When the instincts to virtue signal are combined with curiosity about science, open-mindedness about values and viewpoints, rationality about priorities and policies, and strategic savvy about ways and means, then wonderful things can happen.

Women differ in the exact male height they prefer, but almost always prefer a man taller than themselves. Different ethnic groups may prefer different facial features, but all prefer faces that are symmetrical and averagely shaped for their population. If you don't look for the universals of human beauty at the right level of description, you will not find them.