The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature (65 page)

When our automatic sexual judgments assert themselves, tempting us to discriminate and objectify when we should be sympathizing, we might try remembering the following. First, all living humans are evolutionary success stories whose 80,000 or so genes have already managed to prosper through thousands or millions of generations. Second, all normal humans are incredibly intelligent, creative, articulate, artistic, and kind, compared with other apes and with our hominid ancestors. Third, through the contingencies of human romance and genetic inheritance, almost everyone you meet will produce at least one great-grandchild who will be brighter, kinder, and more beautiful than most of your great-grandchildren. Such lessons in humility, transience, and empathy come naturally from an evolutionary perspective on human nature.

Over the long term, our species, like every other, has just two possible evolutionary fates over the long term: extinction, or further splitting apart into a number of daughter species—each of which will either go extinct or split again. If we avoid extinction, each of our daughter species will probably develop distinctive

styles of courtship display, and different ways to channel their sexual competitiveness into various forms of physical, artistic linguistic, intellectual, moral, and economic display. Some may continue to live on our home planet, and some may move elsewhere. Some may shape their own evolution naturally through sexual selection, while others may shape their evolution consciously through genetic technologies. We cannot imagine the minds that our far-future descendants might evolve, any more than our ape-like ancestors could have imagined ours. That does not matter. Our responsibility is not to speculate endlessly about the possible futures of our daughter species, but to become, with as much panache as we can afford, their ancestors.

Acknowledgments

For useful feedback on various chapters, thanks to Rosalind Arden, David Buss, John Constable, Leda Cosmides, Helena Cronin, James Crow, Oliver Curry, Dan Dennett, John Endler, Dylan Evans, Jennifer Freyd, Kristen Hawkes, Nicholas Humphrey, James Hurford, Marek Kohn, Robert Kruszynski, Henry Plotkin, David Shanks, Peter Singer, Randy Thornhill, and Peter Todd.

For publishing expertise, thanks to my agent John Brockman, my editors Ravi Mirchandani and Roger Scholl, and my copyeditor John Woodruff.

For supporting my research, thanks to the National Science Foundation (USA), the Max Planck Society (Germany), and the Economic and Social Research Council (UK).

For sharing ideas and inspiration related to the book, thanks to the following colleagues: At Stanford University: my Ph.D. thesis advisor Roger Shepard; also, during their 1989-1990 visits, David Buss, Leda Cosmides, Martin Daly, Jennifer Freyd, John Tooby, and Margo Wilson. At the University of Sussex: Margaret Boden, Dave Cliff, Inman Harvey, Phil Husbands, John Maynard Smith, and Michael Wheeler. At the Max Planck Institute's Center for Adaptive Behavior and Cognition: Gerd Gigerenzer, Dan Goldstein, Ralph Hertwig, Ulrich Hoffrage, Tim Ketelaar, Alejandro Lopez, Laura Martignon, and Peter Todd. At the London School of Economics: Helena Cronin, Oliver Curry, Dylan Evans, Nicholas Humphrey, Colin Tudge,

Richard Webb, and Andy Wells. At University College London: Ken Binmore, Chris McManus, Amy Parish, Henry Plotkin, Andrew Pomiankowski, Camilla Power, David Shanks, and Volker Sommer.

Others who contributed important ideas, inspiration, support, and/or feedback related to the book have included Laura Betzig, Robert Boyd, Ellen Dissanayake, Dean Falk, Robert Frank, Steve Gangestad, Arthur Jensen, Chris Knight, Bjorn Merker, Steven Mithen, Randy Nesse, Brad Payne, Robert Plomin, Don Symons, Andy Whiten, George Williams, David Sloan Wilson, and John Ziman.

For their unwavering support and generosity over the years, special thanks to my parents Frank and Carolyn Miller, and to my friends Helena Cronin and Peter Todd.

For choosing me, thanks to my Scheherazade, my partner Rosalind Arden.

Glossary

adaptation
A biological trait that evolved through natural selection or sexual selection to promote survival or reproduction in a particular way.

adaptive radiation
The branching out of a number of species from a common ancestor, as a result of that ancestor having evolved a useful new adaptation that allows it to spread into new ecological niches.

altruism
Helping others without direct benefit to oneself. Apparent altruism can evolve only through indirect or hidden benefits to one's genes.

anthropology
The study of human evolution (physical anthropology) and human cultures (cultural anthropology).

archaic
Homo sapiens
Ancestral hominids that lived in Africa, Europe, and Asia from about 400,000 to about 100,000 years ago, fairly similar to modern humans, with large brains.

archeology
The study of prehistoric artifacts and human remains.

artificial selection
The selective breeding and domestication by humans of other species, e.g. breeding dairy cattle for maximum milk yield.

assortative mating
Sexual choice for traits similar to one's own, e.g. tall women favoring tall men.

Australopithecine
One of a set of hominids that lived about 4 to 1 million years ago; bipedal, with strong jaws and small, ape-sized brains. The earlier ones were probably ancestral to humans.

band
A social group of hunter-gatherers, usually around 20 in number, occupying a local territory

behavior genetics
The study of the inheritance of human and animal behavior, often using twin and adoption studies (to separate genetic from environmental effects) and molecular genetics methods to identify specific genes.

behaviorism
A school of psychology flourishing from about 1920 to 1970, that tried to explain behavior through learned associations between stimuli and responses, without reference

to minds, intentions, behavior genetics, or evolutionary functions.

bonobo
A species of great ape previously known as the "pygmy chimpanzee." Very sexual and very clever, bonobos are found in Zaire and are closely related to the common chimpanzee.

bowerbird
One of the 18-odd species of birds in New Guinea and Australia in which males attract females by building ornamental nests called bowers.

brain size
A convenient indicator of the number and complexity of psychological adaptations that have evolved in a species. Brain size can be estimated from fossil skulls, and correlates 40 percent with intelligence in modern humans.

cognitive psychology
An area of psychology that studies the mental processes that underlie perception, categorization, judgment, decision-making, memory, learning, and language.

cognitive science
The interdisciplinary study of intelligence based on the computer metaphor for the mind, excluding research on individual differences in intelligence, its heritability, or its evolution.

condition-dependence
A trait's sensitivity to an animal's health and energy level. For example, dance ability is condition-dependent because tired, sick animals can't dance very well.

consortship
Exclusive association between a male and a female in estrus, during which the male tries to keep the female sexually separated from other males.

conspicuous consumption
Costly indicators of wealth displayed to achieve social status—the human cultural analog of sexually selected handicaps.

convergent evolution
The independent evolution in separate lineages of adaptations that serve the same function.

copulatory courtship
Energetic, prolonged copulation that provides mutual evidence of fitness through mutual pleasure.

courtship effort
The time, energy skill, and resources spent trying to impress potential sexual partners.

Darwinian aesthetics
The evolutionary analysis of what people find beautiful, by viewing human aesthetic preferences as adaptations for favoring habitats, foods, tools, and sexual partners that promote one's reproductive success.

death
A misfortune that precludes further courtship or reproduction.

developmental stability
An organism's ability to grow a complex body part in its normal form, despite various environmental and genetic stresses. For body parts that are normally symmetrical, symmetry is an indicator of developmental stability.

dimorphism
bodily differences between males and females.
discriminative parental solicitude
The tendency of parents

to direct their care and attention to offspring that are more

likely to survive and reproduce.

display
A conspicuous behavior shaped by evolution to advertise fitness, condition, motivation, or desperation.

dominance
The ability to intimidate other individuals into giving up food, territory, or sexual partners.

ecological niche
The position of a species within an ecology, including its habitat, food supply, and relations to predators and parasites.

equilibrium
In game theory, any situation in which no player can do better by changing their strategy, given what other players are already doing.

equilibrium selection
Any process that leads a population to play one equilibrium rather than another in a strategic game that has more than one possible equilibrium. It can occur through genetic evolution, cultural history, or individual learning.

estrus
Signs of ovulation manifest in a female's body or behavior, evolved to attract males and incite male-male competition.

ethology
The study of the mechanisms and functions of animal behavior in the wild.

evolution
Descent with cumulative genetic modification, due to

natural selection, sexual selection, and various random effects.
evolutionary psychology
The study of human psychological

adaptations, including their evolutionary origins, adaptive

functions, brain mechanisms, genetic inheritance, and social effects.

extended phenotype
An organism considered as a set of adaptive effects that reach out into the environment to promote its

survival and reproduction. It can include evolved traits like beaver dams, spider webs, bowerbird bowers, and hominid handaxes.

female
The sex that produces larger gametes called eggs.

fitness
(1) The relative reproductive success (including survival ability) of one set of genes relative to others. (2) Good physical or mental condition that might prove genetically heritable.

fitness indicator
An adaptation that evolved to advertise an individual's fitness during courtship and mating,

typically by growing an ornament or performing a behavior that a lower-fitness individual would find too costly to produce.

fitness matching
The assortative mating for fitness that happens in a competitive mating market when individuals mate with the highest-fitness sexual partner who is willing to mate with them.

foraging
Finding wild plant and animal foods to eat.

function
How an adaptation evolved to promote survival or reproduction under ancestral conditions.

g
factor
The basic dimension of general intelligence and brain efficiency that accounts for the positive correlations between scores on mental tests. Basically, it is what IQ, tests try to measure.

game theory
The study of interdependent decision-making in situations where each player's payoffs depend on how their own strategies interact with the strategies of other players. Game theory is studied mostly by economists.

gamete
A reproductive cell such as a sperm or egg.

gene
A piece of DNA long enough to code for some biological information but short enough to survive many generations of sexual recombination. The gene is the basic unit of replication and selection in evolution.

gene-culture co-evolution
The hypothesis that the human brain enlarged to learn more culture, which allowed cultures to become more complex, which in turn selected for larger brains, and so forth.

gene pool
The total set of genes in a population.

genetic algorithm
A computer program that evolves solutions to specified problems by applying selection, mutation, and genetic recombination to populations of simulated individuals that represent possible solutions.

genome
The complete set of genetic information in an organism. The human genome contains over 60,000 genes and 3 billion DNA base pairs.