The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature (66 page)

group selection
Competition between groups that favors group-benefiting adaptations such as altruism or equilibria with high mutual payoffs.

handaxe
A stone artifact with a roughly triangular outline, two symmetric faces, and a sharp edge around the circumference. Handaxes were made from about 1.6 million years ago until 50,000 years ago by various hominids.

handicap
A costly, reliable indicator of fitness, often a result of sexual selection.

handicap principle
The idea that fitness indicators can be reliable only if they impose such costs that low-fitness pretenders cannot afford them.

heritability
For traits that vary between individuals, the proportion of that variation that is explained by genetic differences between the individuals. Heritability can range from 0 to 100 percent.

Holocene
The geological era from 10,000 years ago to the present.

hominid
Any of the bipedal apes of the last few million years, whether our direct ancestors or not.

Homo erectus
A medium-brained hominid that flourished from about 1.8 million years ago to about 400,000 years ago (in Africa) and 50,000 years ago (in parts of east Asia).

human nature
The complete set of psychological adaptations that has evolved in our species.

hunter-gatherers
Humans or proto-humans living in small bands without farming or animal herding. Females typically raise the children and gather water, firewood, fruits, tubers, vegetables, berries, and nuts. Males sexually compete by

playing status games such as warfare, hunting, and pretending

to have spiritual powers. Before 10,000 years ago all humans were hunter-gatherers.

ideology
A system of beliefs that has become sufficiently

popular in a culture that believers stand a decent chance of

finding a like-minded mate.

indicator
A trait that evolved to advertise a particular aspect of an individual's fitness, condition, or motivation.

intelligence
Mental fitness, as measurable by intelligence tests and displayed in verbal courtship. In this book, intelligence means the highly heritable "
g
factor" that underlies individual differences in a vast array of behavioral and cognitive

abilities.

kin selection
An evolutionary process that tends to favor generosity to blood relatives, in proportion to their genetic

relatedness.

lek
A place where males congregate to attract females with songs,

dances, and visual ornaments.

lineage
A line of common descent; a succession of organisms

linked by genetic inheritance.

love
An emotional adaptation for focusing courtship effort on a

particular individual.

Machiavellian intelligence theory
The idea that the large brains and high social intelligence of apes and humans

evolved to deceive and manipulate others within a social

group.

male
The sex that produces smaller gametes called sperm.

marketing
Designing, producing, advertising, delivering, pricing, and selling products that satisfy consumer preferences: the economic analog of sexual selection through mate choice.

marriage
A socially legitimated sexual relationship in which sexual fidelity and parental responsibilities are maintained through the threat of social punishment.

mate choice
Choice of sexual partners. This book prefers "sexual choice," which is less confusing for Anglo-Australian cultures, in which a "mate" is a non-sexual friend who reciprocates beer-buying behavior.

m e m e
A unit of cultural information transmitted by imitation.
mixed strategy
A strategy that randomizes behaviors in a

certain proportion to keep an opponent guessing about a

player's next move.

Modern Synthesis
The integration of Darwinian evolutionary theory and Mendelian genetics that was achieved in the 1930s.

monogamy
An exclusive sexual relationship of one male with one female.

morphology
The physical structure of an organism; its body form.

mutation
A spontaneous change in the structure or sequence of a DNA strand that changes how a gene works. Usually a bad idea.

mutation-selection balance
An evolutionary equilibrium in which selection removes harmful mutations at the same average rate that harmful mutations arise.

mutual choice
When both sexes are choosy about their sexual partners.

natural selection
Changes in the gene pool of a species due to differences in the ability of individuals to survive and reproduce. Against current biological fashion, this book follows Darwin in using "natural selection" to cover differences in

survival ability only, and "sexual selection" to cover differences in reproduction ability.

Neanderthal
A species of hominid that flourished in Europe and western Asia from about 300,000 years ago until 50,000 years ago. Stocky, large-nosed, and large-brained, they were apparently not our direct ancestors.

neoteny
The persistence of juvenile traits into adulthood, including bulbous heads, small jaws, and playful gregariousness.

ornament
(1) In biology, a trait that evolved through sexual choice to appear sexually attractive. (2) In aesthetics, a hard-to-

fake display of artistic skill and time, viewed as wasteful decadence by the Bauhaus and other 20th century modernist movements.

ornamental mind theory
The idea that the human mind evolved through sexual choice as a set of entertainment systems used in courtship.

parasite load
The number of parasites carried by an organism. High parasite loads impair condition, reducing health and sexual attractiveness.

parental investment
Any care, protection, or effort given by

parents that increases offspring fitness at a cost to the parent.
phenotype
The observable traits of an organism, including

body and behavior.

Pleistocene
The geological epoch that began 1.64 million years ago and ended 10,000 years ago, during which almost all of human evolution happened.

polyandry
("many men") A sexual relationship in which one female copulates regularly with more than one male partner. Sometimes observed in Tibet.

polygamy
("many marriages") A legal system in which an individual can legitimately marry more than one spouse.

polygyny
("many women") A sexual relationship in which one male copulates regularly with more than one female partner, found in most human cultures throughout history

population
A group of individuals that tend to mate with each other.

population genetics
The area of biology that models how evolution changes gene frequencies in populations.

primatology
The scientific study of the 300-odd species of primates, including apes, monkeys, lemurs, lorises, tarsiers, marmosets, and tamarins.

promiscuity
Mating by a female with many males to maximize sperm competition within her reproductive tract; favored by chimpanzees.

protean behavior
Adaptively unpredictable behavior, as when prey zigzag randomly to escape from predators. Named for the mythical Greek shape-shifter Proteus.

psychological adaptation
An inherited behavioral capacity that evolved to promote survival or reproduction in a particular way under ancestral conditions.

reciprocal altruism
The theory that mutual generosity can evolve if individuals take turns giving and receiving benefits across many encounters.

reportability
The ability to talk about one's subjective experiences.

reproductive success
The number of viable offspring produced by an individual. Reproductive success is the basic currency of evolutionary success.

ritualization
Evolutionary modification of a behavior for greater effectiveness as a display, through standardization, repetition, and amplification.

runaway brain theory
The idea that the human brain evolved through runaway sexual selection.

runaway sexual selection
A positive-feedback process that amplifies the size and complexity of sexual ornaments.

savanna
Open grassland with scattered shrubs and trees, and alternating dry and wet seasons (rather than winters and summers), typical of East Africa where humans evolved.

Scheherazade strategy
Keeping a sexual partner interested in oneself by telling good stories and being a good conversationalist.

selection pressure
Any feature of the physical, biological,

social, or sexual environment that causes some individuals to survive or reproduce better than others.

selfish gene
A gene that acts as if it is trying to replicate itself; the gene considered as the unit of evolutionary selection.

sensory bias theory
The idea that animal senses are more responsive to some stimuli than others, and that this can influence sexual selection to produce ornaments with sensory appeal.

serial monogamy
A mating strategy in which individuals go through a series of monogamous sexual relationships (lasting a few weeks to several years) over the course of their lives. Serial monogamy has probably been the norm in human evolution.

sexual choice
Choice of some sexual partners in preference to others. It has been a driving force behind sexual selection and evolution.

sexual preferences
The criteria for sexual choice, whether perceptual, cognitive, emotional, or social.

sexual reproduction
The production of offspring by combining an egg from a mother with sperm from a father; the prerequisite for sexual selection.

sexual selection
Evolutionary change due to heritable differences in the ability to attract sexual partners, repel sexual rivals, or do anything else that promotes reproduction.

signal
Any behavior that evolved to convey information from one animal (the signaler) to another (the receiver). Most signals convey information about a signaler's fitness, condition, motivation, or location.

social selection
Selection for the ability to promote one's survival and reproduction by attaining social status and managing social relationships, including sexual relationships.

sociolinguistics
The study of the social variations and uses of human language, especially as a function of age, sex, class, and ethnicity.

speciation
The splitting apart of one population to form two species that no longer interbreed with each other.

species
A group of organisms willing to breed with one another. The species is the basic unit of biological classification.

sperm competition
Competition between sperm to fertilize an egg, which occurs when a female has mated with two or more males.

status
Socially recognized merit, often used as a fitness indicator in sexual choice.

strategic handicap
A costly behavioral display, such as dance or speech, that can easily be turned off if an animal is in poor condition. A strategic handicap is very efficient as a fitness indicator.

survival of the fittest
A catchy but misleading phrase invented by Herbert Spencer to describe natural selection, which led biologists to neglect sexual selection.

Theory of Mind
The ability to attribute beliefs and desires to other individuals, in order to better understand their behavior. The theory of mind is a key component of Machiavellian intelligence theory.

tribe
A small society with a distinctive language and culture, typically a cluster of kin groups that interbreed.

universal
Typical of all normal humans across cultures and history, suggesting an evolutionary rather than a cultural origin.
verbal courtship
Talking to attract a sexual partner.