Chris Castig Co-founder of Adjunct Prof at Columbia University Business School.

Sex at Dawn | Summary and Book Quotes

10 min read

The main idea of Sex at Dawn in less than 20 words:

Humans beings were not always monogamous creatures.

Opening Line:

“Forget what you’ve heard about human beings having descended from the apes. We didn’t descend from apes. We are apes.”

My feelings while reading this book:

Shock, endlessly curious, a lessoning of shame, and a reasonable amount of justification for the sexual behaviors of men and women.

What is “The Standard Narrative” and “Pair Bonding”?

Sex at Dawn quote: The Standard Narrative “The standard narrative”  comes up many times in the book. It refers to the common story of love and romantic relationships in our culture, it goes something like this:

  1. Boy meets girls.
  2. They assess each other based on mate value.
  3. Boy gets girl.
  4. Thereafter, the boy is disapproving of her sexual infidelities – while he himself takes advantage of short-term sexual opportunities with other women. (Or to rephrase in my own words: he “cheats”, while she appears to stay faithful).  

Pair bond: is the biological term for when a male and a female getting together to form offspring (and/or a lifelong bond).

My top 3 learnings:

1.  Our ancestors were promiscuous.

2. “We’re more closely related to chimps and bonobos than chimps and bonobos are related to any other primate — gorillas, orangutans, what have you.” This argument supports the book’s thesis that our bodies were once polygamous, and that it’s only with the rise of culture that we’ve been programmed to be more monogamous – hence the contradictions in how we as humans think about monogamy vs. how we act.

3. The Agricultural Revolution is a period of time roughly around 10,000 years ago when humans went from being hunter-gatherers to farmers. Think about that for a second: Humans went from being wild communities that roamed the Earth together to the people we are now today: land owning, hierarchical and individualized. It was a massive shift.

One of the main arguments of the book is that the Agricultural Revolution not only domesticated animals and farm production, but that it also was the beginning of our sexual domestication.

The author’s hope for writing the book

In Christopher Ryan’s TED Talk he explains, “The contradictions between what we’re told we should feel and what we actually do feel generates a huge amount of unnecessary suffering. My hope is that a more accurate, updated understanding of human sexuality will lead us to have greater tolerance for ourselves, for each other, greater respect for unconventional relationship configurations like same-sex marriage or polyamorous unions, and that we’ll finally put to rest the idea that men have some innate, instinctive right to monitor and control women’s sexual behavior. [11:00]”

Book Notes:

In the books introduction: Is there something wrong with your relationship? Well, then, let the experts figure out what ails you, your partner, your relationship. Perhaps his penis needs enlarging or her vagina needs a retrofit. Maybe he has “commitment issues,” a “fragmentary superego,” or the dreaded “Peter Pan complex.” Are you depressed? You say you love your spouse of a dozen years but don’t feel sexually attracted teh way you used to? One or both of you are tempted by another? Maybe you two should try doing it on the kitchen floor. Or force yourself to do it every night for a year. Maybe he’s going through a midlife crisis. Take these pills. Get a new hairstyle. Something must be wrong with you. [5]

“[In this book] We’ll show that human beings evolved in intimate groups where almost everything was shared – food, shelter, protection, child care and even sexual pleasure. …We’ll demostrate that contemporary culture misrepresents the link between love and sex. [6]

“[In this book] We’ll show that human beings evolved in intimate groups where almost everything was shared – food, shelter, protection, child care and even sexual pleasure. …We’ll demostrate that contemporary culture misrepresents the link between love and sex. [6]

Suddenly, women lived in a world where they had to barter their reproductive capacity. [8]

Even if we ignore the roughly two million years since the emergence of our Homo lineage, in which our direct ancestors lives in small foraging groups, anatomically modern humans are estimated to have existed as long as 200,00 years. [9]

Anthropologists have demonstrated time and again that immediate-return hunter-gatherer societies are nearly universal in their fierce egalitarianism. Sharing is not just encouraged; it’s mandatory. [11]

If you spend time with the primates closest to human beings you’ll see female chimps having intercourse dozens of times per day, with most of all of the willing males, and rampant bonobo group sex that leaves everyone relaxed and maintains intricate social networks. Explore contemporary human beings’ lust for particular kinds of pornography of our notorious difficulties with long-term sexual monogamy and you’ll soon stumble over relics of our hypersexual ancestors. [12]

Agriculture and War in Sex at Dawn
Agriculture and War [13]

Clearly, the biggest loser (aside from slaves perhaps) in the agricultural revolution was the human female, who went from occupying a central, respected role in foraging societies to becoming another possession for man to earn and defend, along with his house, slaves and livestock. [14]

An essential first step in discerning the cultural from the human is what mythologist Joseph Campbell called detribalization: We have to recognize the various tribes we belong to, and begin extricating ourselves from the unexamined assumptions each of them mistakes for the truth. [22]

Until Darwin and others began to loosen the link between religious doctrine and scientific truth, guesses about the distant past were restricted by church teachings.  [27]

Blocking the flow of erotic energy creates ever-increasing pressure which is put to work through short, controlled bursts of productivity. Though he was wrong about a lot, it appears Sigmund Freud got it right when he observed that “civilization” is built largely on erotic energy that has been blocked, concentrated, accumulated and redirected. [29]

Romantic love is reduced to a chemical reaction luring us into reproductive entanglements parental love keeps us from escaping [38]

One can choose what to do, but not what to want. [46]

Trying to rise above nature is always a risky, exhausting endeavor, often resulting in spectacular collapse. [47]

An attractive undergraduate student volunteer walked up to an unsuspecting student of the opposite sex (who was alone) on campus of FSU and said, “Hi, I’ve been noticing you around town lately and I find you very attractive. Would you go to bed with me tonight?” 75% of young men said YES, some of the no’s asked for a raincheck. Not one woman said yes. [52]

Conventional theory suggests she’ll marry a nice rich, predictable sincere guy likely to pay the mortgage, change the diapers, and take out the trash – but then cheat on him with the wild, sexy, dangerous dudes, especially around the time she’s ovulating, so she’s more likely to have lover-boy’s baby. Known as the mixed-strategy in scientific literature, both males and females are said to employe their own version of the dark strategy in keeping with their opposed objectives in mating (females maximizing quality of mates and males maximizing quantity of mating opportunities.)”  [55]

Researchers found that women were consistently more upset by thoughts of their mates’s emotional fidelity, while men showed more anxiety concerning their mates’ sexual infidelity. [55]

Women are more likely to cheat on their husbands when they are ovulating. Women are likely to wear more perfume and jewelry when ovulating than at other points in the menstrual cycle.  [57]

If we accept the assumption that women are not particularly interested in sex, other than as a way to manipulate men into sharing resources, why would human females have evolved this unusually abundant sexual capacity? Why not reserve sex for those few days in the cycle when pregnant is more probable, as does practically ever other mammal? [59]

Human females conceals their ovulation [59] vs. the vast majority of other female mammals who advertise when they are fertile. [58]

Sex at Dawn: Old World Monkey Chapter
The ancestral line leading to chimps and bonobos splits off from that leading to humans just five to six million years ago. [62]
The only monogamous ape, the gibbon, lives in Southeast Asia in small family units consisting of a male/female couple and their young – isolated in a territory of thirty to fifty square kilometers. They never leave the trees, have little to no interaction with other gibbon groups, not much advanced intelligence to speak of, and infrequent, reproduction-only copulation. [64]

Monogomy is not found in any social, group-living primate except – if the standard narrative is to be believed – us. [64]

Social Organization Among Apes: 

  1. Bonobo – Multimale – multifemale mating
  2. Chimpanzee – Multimale-multifemale mating
  3. Human – Multimale-multifemale mating
  4. Gorilla – Polygynous mating
  5. Orangutan – Mating is dispersed, infrequent and often violent
    Gibbon -Mating is monogamous. Gibbons establish nuclear family units; each couple maints a territory from which other pairs are excluded. [65]

Modern man’s seemingly instinctive impulse to control women’s sexuality is not an intrinsic feature of human nature. It is a response to specific historical socioeconomic conditions – conditions very different from those in which out species evolved. This is key to understanding sexuality in our modern world. [76]

The pair bond evolved to last only until the infant grows to a child who can keep up with the foraging band without fatherly assistance. [76]

Agriculture has involved the domestication of the human being as much as of any plant or animal. [83]

What gets cultivated – in soil and minds – is not necessarily beneficial to the individuals in a given society. Something may benefit a culture overall, while being disastrous to the majority of the individual members of that society. Individuals suffer and die in wars from which a society may benefit greatly. Industrial poisons in the air and water, globalized trade accords, genetically modified crops… all are accepted by individuals likely to end up losing in the deal. [83]

Our specie’s outstanding feature: our endless complex interactions with each other. [84]

No animal spends more of its allotted time on Earth fussing over sex than Homo Sapiens. Pair-bonded monogamous animals are almost always hyposexual, having sex as the Vatican recommends: infrequently, quietly and for reproduction only. [85]

The phrase rock and roll… it meant ‘to fuck.’ And both jazz and jism likely derive from dinza, the Ki-Kongo word for “to ejaculate.” [86]

In the Amazon, societies share a belief in what scientists call “partible paternity”… a novel conception of conception: a fetus is made of accumulated semen. (ie. from many different men). [90]

As Alfred Kinsey noted back in the 1950s, “Even in cultures which most rigorously attempt to control the female’s extramarital coitus, it is perfectly clear that such activity does occur, and in many instances it occurs with considerable regularity.” Think about that. No group-living nonhuman primate is monogamous, and adultery has been documented in every human culture studied. [98]

Love is an ideal thing, marriage is a real thing. A confusion of the REAL with the IDEAL never goes unpunished. – Johann Wolfgang Von Goethe [113]

french cuckoldry - from sex at dawn
1815 French satire on cuckoldry, which shows both men and women wearing horns.

Sexual selection’s primary literature describes extrapair parentage as ‘cheating‘ on the pair bond; the male is said to be ‘cuckolded‘; offspring of extrapair parentage are said to be ‘illegitimate‘; and females who do not participate in extrapair copulations are said to be ‘faithful.’ This judgemental terminology,” concludes Roughgarde, “amounts to applying a contemporary definition of Western marriage to animals.” [117]

So is jealously natural? It depends. Fear is certainly natural, and like any other kind of insecurity, jealousy is an expression of fear. [147]

Why is it so easy to believe that a mother’s love isn’t a zero-sum proposition, but that sexual love is a finite resource? Evolutionary biologist Richard Dawkins asks the pertinent questions with characteristic elegance: “Is it so very obvious that you can’t love more than one person? We seem to manage it with parental love (parents are reproached if they don’t at least pretend to love all their children equally), love of books, of food, of wine (we don’t feel unfaithful to the red when we dally with the white), love of composers, poets, holiday beaches, friends… why is erotic love the one exception that everybody instantly acknowledges without even thinking about it?” [148]

Malthus argued that each generation doubles geometrically (2,4,8,16,32…), but farmers can only increase food supply arithmetically, as new fields are cleared and productive capacity is added in a linear fashion (2,3,4,5,6…).  [154]

Malthus’s brutal conclusion: chronic overpopulation, desperation and widespread starvation are intrinsic to human existence. Helping the poor is like feeding London’s pigeons; they’ll just reproduce back to the brink of starvation anyway. So what’s the point? [154]

estimated human population - sex at dawn
Estimated Global Population [156]

“We are enriched not by what we possess, but what we can do without” -Immanuael Kant [158]

“Poverty… is the invention of civilization.”  – Marshall Sahlins [161]

Human beings aren’t very good at dealing with the dubious freedoms conferred by anonymity. When communities grow beyond the point where every individual has at least a passing acquaintance with everyone else, our behavior changes, our choices shift, and our sense of the possible and the acceptable grows ever more abstract. [171]

Set loose in anonymity, we become a different creature. [172]

The conditions necessary for devastating epidemics or pandemics just didn’t exist until the agricultural revolution. The claim that modern medicine and sanitation save us from infectious diseases that ravaged pre-agricultural people (something we hear often) is like arguing that seat belts and air bags protect us from car crashes that were fatal to our prehistoric ancestors. [208]

Every creature’s body tells a detailed story about the environment in which its ancestors evolved... Its teeth and digestive system contain information about the primordial diet. It’s eyes, legs , and feet show how its ancestors got around. The relative sizes of males and females and the particulars of the genitalia say a lot about reproduction. [215]

The process is something of a lottery, where the male with the most tickets has the best shot of winning (hence, the chimp and bonobo’s huge sperm-production capabilities). [220]

sex at dawn - ape mating systems image
Multiple Comparisons of Ape Anatomy [224]
A human ejaculation typically consists of anywhere from three to nine spurts. Researches who somehow managed to capture “split ejaculates” for analysis found that the first spurts contain chemicals that protect against various kinds of chemical attack (they protect the sperm from the chemicals in the later spurts of men’s ejaculate). These final spurts contain a spermicidal substance that slows the advance of any latecomers. In other words, competing sperm from other men seems to be anticipated in the chemistry of men’s semen, both in the early spurts (protective) and in the later spurts (attacking). [228]

Despite all the controversy, there is no question as to whether sperm competition occurs in human reproduction. It does – every time. A single human ejaculate contains anywhere from fifty million to half a billion applicants all trying to elbow their way into the only job available fertilizer in chief. [229]

More recently, several researchers have demonstrated that a man’s sperm production increases significantly when he has not seen his partner for a few days, regardless of whether or not he ejaculated during her absence…. this leads a man’s body to hyper-produce sperm to increase his chances of fertilizing her ovum (after a prolonged absence). [228]

The act of swearing on one’s balls lives on in the word testify. [234]

“Adult male humans have the longest, thickest, and most flexible penises of any living primate [234]

On semen displacement: This vacuum pulls any perviously deposited semen away from the ovum, thus aiding the sperm about to be sent into action. Using artificial semen made of cornstarch, researchers showed that 90 percent of the cornstarch mixture was displaced with just a single thrust of their lab penis. [235]

Despite all the bad press they get, men last far longer in the saddle than bonobos (15secs), chimps (7 secs), or gorillas (60 secs), clocking in between 4 and 7 minutes on average. [236]

A scrotum is like a spare refrigerator in the garage just for beer, if you’ve got a spare beer fridge, you’re probably the type who expects a party to break out at any moment. You want to be prepared. A scrotum fulfills the same funciton. By keeping the testicles a few degrees cooler than they would be inside the body, a scrotum allows chilled spermatorozoa to accumulate and remain viable longer (if needed). [237]

Researchers found that men who had ejaculated more than five times per week (between the ages of twenty and fifty) were one third less likely to develop prostate cancer later in life. [238]

Daily ejaculation dramatically reduced DNA damage to sperm cells (contrary to conventional wisdom) [238]

Infertility can’t be inherited. [239]

In a monogamous mating system, there is no sperm competition with other males. Sex becomes like an election in a dictatorship: just one candidate can win. So, even a man with impaired sperm production is likely to ring the bell eventually, thus conceiving songs (and perhaps daughters) with increased potential for weakened fertility. [239]

The average human has sex 1000 times since birth.

Adult male Danes have testes that are more than twice the size of their Chinese equivalents. [241]

The sheer amount of time spent in sexual activity by human beings easily surpasses that of any other primate – even if we agree to ignore al our fantasizing, dreaming, and masturbating. [242]

Women use clothes as a way to signal their period of fertility, the “hidden ovulation”, similar to how the female-chimps “red light district” (butt) lights up during ovulation. [262]

The female body perceives sperm as antigens (foreign bodies) that are promptly attacked, 100:1. [264]

The male’s quick orgasm lessens the chances of being interrupted by predators. [265]

“A man is basically as faithful as his options.” – Chris Rock [291]

“The prerequisite for a good marriage, it seems to me , is the license to be unfaithful.” – Carl Jung, 1910 [293]

Kinsey concurred, writing, “There seems to be no question but that the human male would be promiscuous in his choice of sexual partners throughout the whole of his life if there were no social restrictions. [294]

Without testosterone, he had no desire. [296]


Title: Sex at Dawn
Author: Christopher Ryan and Cacilda Jethá
Hardcover: 432 pages
Publisher: Harper Perennial (July 5, 2011)
Buy Sex at Dawn on Amazon

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Chris Castig Co-founder of Adjunct Prof at Columbia University Business School.