Acknowledgement: This work has been summarized using the Penguin Book 1994 edition. Quotations are for the most part taken from that work, as are paraphrases of its commentary.
Overall Impression: This is a rather wordy book that is filled with details but a little shy on well demarcated conclusions. There are no diagrams or other helpful visual aids that might be expected, just pure text. The author studied zoology before becoming a journalist and science writer.
The nature of human nature is the theme of the book, how it evolved, how human sexuality evolved. Reproduction is the sole goal for which human beings are designed. Nothing in our natures has not been carefully chosen. Reproductive success is the examination that all human genes must pass.
Human culture is a product of human nature, not just of our free will or invention. We have laws against racism that allow persons to calculate the consequences of violating them though they may be acting racist because of human nature.
Richard Dawkins 1970s argues that the body is merely an evolutionary vehicle for our genes--the genes force the body to do things to perpetuate them. There is selective competition for genes.
The human brain developed current its form and capacity 3M to 100K years ago on African savanna--100K years is only 3000 generations ago. 30 generations back, in 1066, you had a billion ancestors [probably with considerable overlap]. The differences between individuals are attributable to individual variation (85%), tribal/national variation (8%), and racial variation (7%).
People are attracted to people of high reproductive potential, the consequences of which are sexual selection. Even behavior is adapted to this goal. We are descended from men who preferred fertile women. The goal is not just to survive but to breed. The human intellect itself has evolved to contribute to reproductive success.
Time erodes any temporary advantage, progress is relative and futile, the struggle is Sisyphean. The Red Queen concept derives from Lewis Carroll "Through the Looking Glass": The faster you run, the more the world moves with you and the less you make progress. ("However fast they went, they never seemed to pass anything.") Marriage is a blend of or balance between cooperation and exploitation/conflict.
What is the purpose of sex? It is the queen of evolutionary problems. Sex is bothersome and yet has persisted tenaciously. We have 75000 x 2=150000 genes in 23 pairs of chromosomes. Gametes have 75000 genes which have been intermixed (via recombination) in meiosis. Further mixing takes place when the gametes fuse (outcrossing). Thus the baby gets a thorough mix of the genes of the 4 grandparents.
Sex is a source of individual variability furnishing material for the operation of natural selection. This is the "Vicar of Bray" hypothesis, which emphasizes rapid adaptability to change. But mankind's greatest rival is mankind. We use our intellects to outwit each other. Animal altruism is a myth.
George Williams argued how collective effects could flow from the actions of self-interested individuals. A creature would evolve to help its species only if its self-interest coincided. There is a cost to sex... Are males worth it? Many animals and plants have abandoned sex or only resort to it intermittently. Sex serves the species but at the expense of the individual...
Harris Bernstein argues that the main purpose of sex is to repair genes... This is useful but probably not the entire purpose of sex.
Sex breaks up the linkage of one gene with another, increases randomness. Thus it might help to get rid of bad mutations (which inevitably accumulate: Muller's ratchet). Sex is more necessary if you are big and do not belong to a huge population with rapid reproduction. Sex throws the ratchet in reverse. Ultimately, there is no purely genetic explanation of sex.\
Bdelloid rotifers do not employ sex, can dry up and blow about as tuns.
Graham Williams describes the "Tangled Bank" hypothesis: in a saturated economy, it pays to diversify.
Longer-lived mammals exhibit more chromosomal crossovers: 30 in man, 10 in rabbits, 3 in mice.
The Red Queen hypothesis: species do not get any better at surviving, their chances of extinction are random. "It takes all the running you can do to keep in the same place. If you want to get to somewhere else, you must run at least twice as fast as that. [Carroll]" Sex is all about combating the enemy that fights back (parasites [including microbes], predators and competitors). Parasites are especially deadly. You never win, you only gain a temporary respite. Virulent parasites versus ones that do not kill their hosts. Artificial viruses (computer programs). Parasites employ binding proteins, which the host evolves and varies. The advantage of sex can appear in a single generation when it comes to parasites. Variation arises from heterozygosity and also from population-derived polymorphism. Heterozygosity can improve survival (e.g.. sickle cell vs. malaria). Polymorphic blood group genes affect disease resistance and is maintained by disease predation.
Immune system would not work without sex...
William Hamilton's computer model of sex and disease. When parasites are introduced, the sexual organisms do better than the asexual. Antiparasite adaptations are in constant obsolescence.
To properly compete, parasites also need sex.
Studies reinforcing the Red Queen/parasite hypothesis include the New Zealand water snails and the Mexico topminnow.
Genetic insertions (jumping genes, transposons)...
Red Queen is only a part of the explanation for why we are sexual.
There is intragenomic conflict. Genes are active and resemble cunning individuals. When it acts to enhance its own survival, this is an effective strategy. Must find right balance between cooperation and competition.
Conjugation by paramecia and bacteria is used to transfer genes, is not a type of reproduction. It serves the purposes of the genes and not the bacteria. For genes, sex is a way to spread laterally as well as vertically. Transposons (jumping genes) are genes which can cut themselves out of one chromosome and insert themselves into another. Some plasmids actually provoke conjugation. The distinction between a rogue gene and a virus is indistinct.
Genes are full of half-suppressed mutinies, selfish chromosomes. A segregation distorter gene in a fruit fly can kill all sperm containing the other copy of the chromosome, so that all sperm produced that survives contains the segregation distorter gene. It is like Cain, which kills Abel--a fratricidal gene. Processes like these are called "meiotic drive" because they drive the process of meiosis into a biased outcome. These are rare, are defended against by recombination or swapping ("crossing over") in meiosis. The Y chromosome is not recombined and the X chromosome is especially susceptible to Cain genes that kill the Y gene (male-killer genes)...
Definition of Male (many small mobile gametes) vs. Female (few large immobile gametes). Organelles (mitochondria, chloroplasts) are descendants of bacteria. Mitochondria have 37 genes of their own, all from the mother: the father's sperm's organelles are excluded from the fertilized ovum with great thoroughness. Suicidal organelles... Sperms leave behind their organelles (mitochondria and flagellum) at the egg membrane, only the nucleus enters. This prevents introducing infection--safe sex.
Gender was invented as a means of resolving the conflict between the cytoplasmic genes of 2 parents [dogmatic?]. All cytoplasmic genes come from the mother.
Why are we not hermaphroditic (as in most plants) instead of dioecious (2 separate genders, typical of mobile species)?...
Sex-ratio distorters in turkeys, wasps. Human families with only daughters have a cytoplasmic gene which feminizes every embryo, even those that at puberty will appear male.
Lemmings. The "Driving Y" which causes the death of X-bearing sperm, assuring male offspring. Infinite series of rebellions. Multigender organisms. Female biased sex ratio in lemmings.
How gender is determined: (1) Chooses gender appropriate to sexual opportunities. (2) Leave it to environment (3) Mother determines sex of each child. The genetic lottery for sex determination is not incompatible with sex allocation. Of American presidents, 60% of children have been male...
The Trivers-Willard theory posits that parents in good condition probably have male-biased litters while those in poor condition will have female-biased litters. Dominant females are more likely to have sons than daughters (in red deer)...
Can human gender be preselected? Infanticide of females. High levels of maternal HCG increase prob. of female, and high testosterone in father of sons. But true control of gender as might be desired by dairy farmers has not proved possible despite considerable effort. Cultural variation in preference for boys versus girls. Daughters are preferred in poor cultures because they are more likely to lead to grandchildren, can marry up, etc. The ability to choose preferably the male sex would benefit the individual but would be a tragedy of the commons.
The showy tail is the peacock's way of attracting the peahen. Sexual selection has selectively bred this trait. Males invest less in childrearing than females in most but not all species (e.g., jacana). In elephant seals, only a few males father all the offspring. Beauty arose to satisfy the Red Queen contest. Previously bright colors were seen as a warning to predators. In peacocks and other birds, size (and symmetry) of plumage matters. Exaggerated gaudy ornaments burden the males (in terms of longevity and protection from predators) but are the key to successful mating. Females prefer them because other females prefer them--fashion is arbitrary . Polygamy... Most of the peahens choose the same male. Bird leks (places where males gather, parade their wares to the visiting females. Only a few males do most of the mating--up to 30 times in one morning).
Dichotomous sexual selection theories:
(1) Fisher (Sir Ronald Fisher) sexy-son Good-taste: females prefer beautiful males because the heritable beauty will be passed on to sons who will attract females.
(2) Good-gene good-sense healthy-offspring (Alfred Wallace): peahens prefer beautiful males because beauty is a sign of good genetic qualities incl. diseases resistance.
Computer modeling favors the Fisherians to some extent...
Ornaments are handicaps to survival from predators but increase ability to seduce females. They are also living proof of the male's vigor that he has been able to survive with it. The more flamboyant or symmetrical a male's appearance, the less troubled with parasites he is. Successful males are not necessarily truthful, sometimes just more persuasive. However, red carotenoid pigments in male facial sexual appendages are indications of low parasitism. The better songsters in birds (nightingale) are less visibly showy, since visual appearance plays a lesser role. Young women in their breeding prime have narrow waists to suggest large breast tissues and wide hip bones suitable for reproduction.
Female taste is idiosyncratic. Of zebra finches, the more red the more attractive is the male.
In humans, attractiveness is not just about appearance but also wittiness, cleverness, etc.
We are designed for a system of monogamy plagued by adultery. Polygamy flourishes where it is allowed [is this contradictory?]. 3/4 of tribal cultures are polygamous. Powerful men have always had more than one mate, though usually only one legitimate wife who produces the heirs. Males are usually the seducer, women the seduced (exception: jacana, phalarope).
Homosexual promiscuity: Homosexuals are generally more promiscuous than heterosexuals. Male homosexuals are acting out male tendencies unfettered by the pressure of women toward monogamy. Lesbians are rarely promiscuous.
Harems and wealth. There is a polygyny threshold in which a suitably advantaged male attracts more than one mate, even in humans. It applies to humans regarding cattlemen of Kenya. Although first wives resent the new arrivals, the subsequent wives are receiving companionship, job sharing, and comfort (even career enhancement due to decreased responsibility). The mating system chosen is influenced by the distribution and population density of females.
Hunter gatherers... Sexual division of labor. Men seek power and building or dominating male-male coalitions. Men can always increase their reproductive success by philandering. Equitable sharing of hunted food is reciprocal altruism.
Chimps rise to alpha male status with cunning and coalitions as well as physical prowess. Coalitions in species can be based on reciprocity or relatedness.
Emperors have large harems. The more polygamous societies have male inheritance.
Laura Betzig posited via historical review that power in cultures is used for sexual success. Young virgins are recruited and guarded. Emperors become breeding machines with "onerous" duties. There is always one legitimate queen with legitimate heirs.
Slaves have been equated to concubines in Rome, etc. Many women were "employed" in castles and monasteries (in "gynoeciums" [women's apartments]).
For males, violence is rewarded by greater reproduction. Christians equated sex and sin prob. because of the trouble it leads to. Of Pitcairn survivors, many women but only 1 man survived due to sexual competition. Monogamy reduces murderous competition.
Chimps exhibit intergroup violence, killing the males of nearby groups and taking over the females. So do the Yanomamo's of Venezuela--they fight over women (this was disbelieved initially by anthropologists). The Iliad is a war over women. Armies are motivated over rape, as in Serbia. Democracy and the abolition of despotic power breeds monogamy.
Polygamy is infrequent in hunter gatherers (exceptions: PNW Indians and Australian aborigines). Marriage is a child rearing institution. Women are not interested in overt polygamy but are often unfaithful. The Herod effect: Sarah Hrdy. Sperm competition theory. Female chimps have steady mates but sneak out to mate with a top male. Infanticide by a male mate halts maternal milk production and prepares them for new pregnancy. Female chimps mate with many males to share paternity and prevent infanticide. Human stepchildren are 65x more likely to die than children living with their parents [can this be true?]. Promiscuity and peacefulness of bonobos (pygmy chimps)--mating is so frequent it rarely leads to aggression.
Women seek monogamous marriages, lesbians are not promiscuous. Women are sometimes unfaithful. Species in which males have bigger testicles have more female polygamy [is this cause or effect?]. This allows more effective sperm competition. Man's are medium sized, with unusually low sperm/gram tissue. For birds, many of the chicks are not the ostensible father's--the fathers are cuckolded. Testicles are largest in polyandrous birds. Birds with large testicles tend to live in colonies where the females have ample opportunity for adultery.
A female with a mediocre husband having with good territory should have an affair with a genetically superior husband (the Emma Bovary strategy). Attractive males make inattentive fathers.
The amount of sperm retention in the vagina depends on orgasm. Faithful women and ardent lovers have high sperm retention (high fertility) orgasms compared to unfaithful women with their spouses (Baker and Bellis). Men and rats who have been away ejaculate more than ones who have been with the female all day (to overcome competition from other sperm).
Male birds behave in constant terror of infidelity of their females and mate frequently to compete (e.g., goshawks). Men keep an eye on their wives by proxy, gossip--for which language is required.
Human females have concealed ovulation, forcing males to mate regularly, exhibit continual sexual interest. This helps to prevent infanticide--neither the husband nor the lover knows if he is the father. Women use perpetual sexual availability to seduce philanderers in exchange for gifts.
Males may hold 2 territories, each with a committed mate. Men deceive their wives, not their lovers.
Jealousy is deep seated in men, a human universal. The absence of jealousy in a husband is worrisome to a wife. Couples who exhibit occasional jealousy are more likely to stay together. Men are less accepting of infidelity in their wives--there is also a legal double standard [really?].
Courtly love is about passing wealth to sons so they can be successful adulterers, cuckolding heiresses. Jousting impressed the ladies [and facilitated these relationships?] Tristan... The Church became obsessed with sex to prevent lords from siring legitimate heirs [can this be true?]. In the American South, the effort was to keep the wealth in the family. Incest laws are in part an effort for rulers to prevent wealth concentration in other families (and are not always followed by the rulers).
Men want to acquire power and use it to lure women who will bear heirs, and to acquire wealth to buy other men's wives who will bear bastards. Wealth and power are a means to women which lead to genetic eternity. Women want a husband who will provide care and food for her children, and a lover who will give them first-class genes.
Cites objective evidence for gender differences in the brain: bigger hippocampi in male voles etc.
Males evolved to fight in the male hierarchy and hunt. Men are more violent, women more nurturing. Male apes that show aggression are rewarded.
Girls are better at verbal tasks, boys are better at mathematical tasks, boys are more aggressive, boys are better at some visuo-spatial tasks (e.g., rotation, throwing spear at moving target, making tools), and girls are better at others (spotting mushrooms, berries, plants)...
Females of phalaropes and jacanas, who play the dominant roles over males, have higher testosterone than males. Turner's S. pts have decreased testosterone and are more hyperfeminine in behavior. Men with less intrauterine testosterone are less assertive, more shy. The first pulse of testosterone in the uterus primes the male, the second during puberty develops the full male effects.
Baby girls do more smiling and communicating, boys do more playing with things. Boys are more fidgety, inattentive, girls better at linguistic forms. Kibbutzes tried to make sex roles uniform but failed. Feminism is not egalitarian--it is trying to change the nature of men while insisting that women are unchangeable. Women are slightly better than men at running countries.
Male homosexuality is fixed before adulthood. LH may have to do with it. Prenatal deficiency of testosterone increases likelihood of being male homosexual, as are XXY and men exposed intrauterine to female hormones or conceived in times of great stress. Homosexuality is more common in left handed males. Growing evidence that it is partly genetically determined...
Rich men marry beautiful women. Women pay attention to cues of wealth and power, men pay attention to cues of health and youth.
Sexual fantasies are greater in men, more ubiquitous, visual, specifically sexual, promiscuous, and active, often involve strangers--in women they are more of familiar partners, more contextual, emotive, intimate, passive. Men like pornography, women like romance novels. Images of women in pornography are more arousing to men and to women.
Marriage has a natural period of c. 4 years. Men often seek younger wives.
The racial differences between men are minimal compared to the differences between men and women. Sexual role playing is universal: men pursue and acquire while women are protected and bartered.
If an identical twin is gay, the other twin is gay 50% of the time. Is there a gay gene? The genes of mitochondria may carry the gay gene [evidence?]...
Beauty is universal but standards applied differ.
Incest taboo may consist of dislike of mating with those we grew up with and knew well in childhood. Nancy Thornhill concludes incest taboos are actually rules about marriage customs invented by powerful men to prevent rivals from accumulating wealth by marrying their own cousin. Aversion to mating with childhood familiars wears off in later life.
Imprinting of chicks toward their mothers occurs at 13-16 hours in chicks and goslings. Similarly, Westermarck says we become sexually indifferent to those with whom we were reared during a critical period, c. 8 - 14 y/o.
Skinny women became a prejudice in the 1950s, ..., a religion in the 1980s. Victorian women were not thin. Most tribal peoples prefer plump women. Thinness is now a sign of status. Status consciousness and sexual selection means that males may now select females who will bear thin daughters who will themselves attract men who prefer thinness.
Waists matter because men prefer women whose waist if much thinner than her hips--the ratio matters more than the absolute measurement. This is gynoid fat distribution (hips and breasts fat predominate) cf. android fat distribution (belly fat predominates). Men have selectively if subconsciously bred women with hourglass bodies. Choosing broad hipped women allows babies to have largest brains at birth--men are left with the impression that a hourglass figure represents large hips and better childbirth potential.
Role of blond hair--found mainly in young women, leading to a sexual preference for blondes.
Facial symmetry is a key to beauty. Face is information dense. The computer-averaged face is more beautiful than any explicit extreme example. Faces of models are often forgettable. A beautiful woman can always marry above her station.
Women are attracted to men for their personality and status more than for their beauty and figure. Height however is universally considered attractive. A man must be taller than his date. One inch is worth $6000/year in salary; height contributes to self-assurance. Body language contributes to male sexiness. Character is important in male stars. Male handsomeness depends on skills and prowess.
Women are impressed with symbols of status, fashionable clothes. Men think women care more about male physique than they do, women think men care about status cues more than they actually do.
Fashion is obsessed with novelty, conspicuous display. Fashion is change and obsolescence imposed on a pattern of tyrannical conformity.
Eugenics will never work, standards of beauty change. Beauty cannot exist without ugliness. We each instinctively know our relative worth.
Brains are large in dolphins (1500 gm) in part to deceive. Lucy the Australopithecus afarensis had brain size 400 c.c.s (bigger than chimp, smaller than orangutan). Current human capacity is 1400 c.c.s. Brain growth occurred because of Red Queen sexual selection.
Chomsky theory of hard-wired deep structure in brain preprogrammed to learn language. But vocabulary and syntax is plastic and variable.
Dogma of sociologists (Emil Durkheim) 1895: anything that varies between cultures must be culturally rather than biologically determined. M. Mead argued that sexual practices were largely the product of nurture. Aversion to sociobiology, which seemed to provide justification for prejudice.
The brain has modules designed by evolution which are specialized mechanisms to recognize faces, read reactions, fear snakes, infer semantic meaning, etc.
Man is not the only tool user. He made tools c. 2.5 M years ago Oldowan technology. Man is not the only skilled hunter.
18% of our energy goes to the brain. Evolution of intelligence is not neutral. Concept of neoteny (retention of juvenile features into adult life)--more a feature of man than of other animals. Need for recursion in narrative speech [?].
Value of gossip. Man applies his intelligence in social situations. Consciousness operates on a need-to-know policy. The greatest minds are mind-reading minds: Jane Austen, Shakespeare. Animals use communication primarily to manipulate one another rather than to transfer information. Laws are easier to enforce when they are presented as part of social contract.
Deceiving and detecting deception are the primary uses of intelligence. Deception is the reason for the invention of the subconscious.
According to Geoffrey Miller, the neocortex is largely a courtship device to attract and retain sexual mates. Hominid males and females became satisfied with nothing less than psychologically brilliant, fascinating, articulate, entertaining companions. Sexual selection can complicate rather than assist the problems of survival. Women need to have the creativity and variety of Scheherezade (Scheherezade effect) to keep their husband around for years--men need the Dionysus effect to do the same (dance, music, intoxication, and seduction). Larger brains require longer period of maturation in the offspring, thus long-term bonds are required.
Dance, music, humor, and sexual foreplay are unique to humans. Sexual fascination of music is obvious.
Neoteny and obsession with youth...
The head is the human equivalent of the peacock's tail according to sexual selection theory, but this connection is tenuous. Wit, virtuosity, inventiveness, and individuality turn people on. Be different.
The study of human nature is at an early stage.. Human communities always invent a hierarchy and always atomize into possessive sexual bonds...