Lynn Saxon's Blog

My name is still Lynn Saxon...

and I have now written The Naked Bonobo. Someone needed to.
     Marlene Zuk, in her 2002 book Sexual Selections, called bonobos the dolphins of the new millennium. I don’t think bonobos have yet reached the level of appeal achieved by the dolphin but they might be getting there, and that’s reason enough to seek out what we really know about them.
     Zuk remarks that when we look for reflections of ourselves in other species we easily miss seeing what those species are actually doing. This was well illustrated recently when images of a male kangaroo apparently grieving over a dying female, spread around the globe. But then we were informed by an expert that the male kangaroo was actually trying to have sex with the dying female, and his sexual intentions may well have been what caused her death.
     Nature fluffified may lift our spirits but reality has the habit of knocking them back down again. And this can be so whether our spirits are lifted by a March of the Penguins-style monogamy story or the free-lovin’ one of the bonobo. A cute story can be made of any species’ behaviour.

     So, what are bonobos actually doing?
     The real bonobo turns out to be an ape rather different from the one currently being portrayed in the media. The image of the bonobo we are currently being fed is one of constant friendly sexual contacts leading to a chilled-out, caring, sharing society: the ultimate make love, not war species. Very cute.
     It turns out, though, that while sex (in terms of some sort of genital contact) does help avoid most serious physical aggression, it is often not friendly. For example, Takayoshi Kano, who led the early research at the Wamba research sites, writes that when males approach each other it is not with friendly intentions but the male’s intention is one of dominance, and the prevailing mood is hostile. Most male sexual contact is in the context of aggression: the attacking male “may spring on a male, who, cut off from escape, is grovelling and screaming, and the attacker will mount or rump-rub the victim. Or the attacker may confront his victim, suddenly facing the victim’s buttocks and demanding mounting or rump-rubbing.”
     We would call this kind of behaviour in humans sexual assault, but in bonobos we call it making love!
     Forced sex is not what we have been led to believe occurs in bonobos, yet this kind of forced mounting of males occurs, Kano says, frequently. And though Kano did not see forced heterosexual sex, this too has occasionally been seen by other researchers. What’s more, ‘bending over’ (adult males are not much interested in face-to-face sex) is a common response from either sex towards an aggressive adult male. It is not friendly, casual, chilled-out sex leading to lower levels of violence; it is agitated, aggressively displaying males being calmed, willingly or not, by others.
     It’s not that ordinary soliciting of sex does not occur, but sex during times of social stress and anxiety accounts for most bonobo sex. And when it comes to bonobo heterosexual sex, it is the young, adolescent, low-status females who are involved in most of that sex, and precisely because they are low-status. Add to this that much of the bonobo sexual behaviour smorgasbord we hear about, such as fellatio and kissing, is almost exclusively the behaviour of sexual immatures, and bonobo sexual behaviour becomes less and less a reflection of our own.
     Whether homosexual sex, heterosexual sex, sex between adults and immatures, competition, aggression, or female status, we are long overdue the facts and figures on what the bonobos are actually doing. This is what The Naked Bonobo provides.

Daniel Bergner and the Mystery of Lost Libidos

It’s not surprising that Daniel Bergner in What do Women Want does not follow up the one distinction he briefly notes between the rhesus monkey and the human female: the impact of ovulation. We all tend to take it for granted that human females will have sex regardless of where they are in their reproductive cycle. The adaptive function of this ‘constant receptivity’ is argued (at one extreme) as making sexually monogamous pair bonds possible or (at the other extreme) sexual promiscuity.
     Frank Beach (famous for his studies of animal, including human, sexual behaviour) remarked:"No human female is ‘constantly sexually receptive’. Any male who entertains this illusion must be a very old man with a short memory or a very young man due for bitter disappointment.” The capacity of many primate females to engage in sex outside of oestrus has long been confused with their actual desire to do so.

     In his search for women’s lost libidos Bergner takes us to work done by Meredith Chivers. This research tells us about the disconnect between the genitals and the minds of women: women’s genital arousal (blood flow and lubrication) appears to respond to pretty much anything sexual even when the women report that they do not feel sexually aroused. Has the mystery of lost libidos been solved? Is the answer here in these genital measurements? Has Woman’s naturally rampant sex drive been blotted from her mind by millennia of cultural suppression?
     But then we also learn that women are aroused by depictions of sexual coercion, and we also now know that rape victims can experience genital arousal and even orgasm. Adding, as Bergner does, that “arousal is not consent” does little to allay concerns arising from the implication that women’s bodies do really want the ‘unwanted’ sex and it is just their minds that are getting in the way, like some kind of psychosomatic disorder that needs to be fixed. If women’s bodies are aroused by depictions, or actual experience, of sexual coercion, is this evidence of what they ‘naturally’ really want? Bergner clearly interprets women’s genital arousal as a genuine sign of being “turned on”. In this he comes close to Christopher Ryan’s view in Sex at Dawn that a woman’s body knows better than her mind – and this is but a short step away from Todd Akin’s “legitimate rape”.

     Bergner dismisses Chivers’ proposal that the female genital response is a protective reflex to prevent injury and infection that might otherwise occur due to unwanted sex. I agree that Chivers’ coerced sex scenario seems overly ‘sex negative’ but having spent some time on the literature surrounding this subject the evidence is clear that this genital response is an automatic reflex. But could it be an automatic reflex because whenever there is any possibility of sexual activity it would invariably be a darn good thing to get active too?
     I think part of our problem is that we start from a position of assuming a natural, constant female receptivity – or even proceptivity, the term introduced by Beach in the 1970s to describe the active solicitation of sex by females which was at last being acknowledged. Starting from this position we then assume an absence of desire to be the problem. But if, instead, we start from the position of ancestral primates with a distinct oestrus, and look at how and why they mated beyond this period, then perhaps we can gain more insight into the evolution of female sexuality.
     The bodies of oestrous females are hormonally prepared for sex which includes protection of the vagina against injury and infection. So if sex beyond this period becomes an adaptive behaviour for the female then we would expect there to evolve a mechanism to protect the vagina at these times too. For a male things are relatively straightforward in that he has a fairly constant sexual response to signals of fertility in females and nothing new needed to evolve, but the female response had to change a lot: she not only had to appear more constantly sexually attractive to the male but to have a vagina that was prepared for sex.
     So, what situations do our primate cousins experience where they gain benefits from this non-fertile sex? A few examples:

Sex with novel males to ‘confuse paternity’ and prevent infanticide is one situation which is now well documented across primates and other species.

In my previous blog I wrote about the female rhesus monkey being receptive to sex throughout her reproductive cycle when she is put together with a male in a cage for a “pair test”. Avoiding sex is not an option. So receptivity to sex when unable to escape a sexually aroused male could be another situation-dependent female sexual behaviour.

At the end of Sex at Dusk I wrote about a female gorilla soliciting sex with the silverback though she was not fertile. This behaviour was due to the presence of another female who was fertile so this is competition between females for the attention of the male. Again this is a situation-dependent sexual behaviour by the female.

Bonobos have the most non-conceptive sex next to humans but again it is often situation dependent (as I wrote about at length in Sex at Dusk). For example, young females entering the group use sex to get close to resident, high-status females and males so as to increase their own social status and ultimately get to the food. Sex is clearly often used strategically, and high status females engage in less sex because they can have access to food without it.

     It is clear that for female primates sex is often about something other than sex per se, so it becomes less of an oddity that the brain should be so much more involved in the decision whether or not the situation really does require sexual activity or not. This suggests that the female genital reflex is not just about protection against coerced sex, though that can be one situation females experience, but more about being prepared for sex which may or may not occur, and which may be initiated by the female as a means to some other end. It is not that she does not want the sex but that the sex is not the ultimate goal.

          Daphne: “Oh, come now Dr Crane. It’s not like men have never used sex
                              to get what they want."
          Frasier: “How can we possibly use sex to get what we want? Sex IS what
                              we want."
          (From the 1995 “Sleeping with the Enemy” episode of Frasier.)

     None of this is to deny the female capacity to feel the kind of sexual desire that a man also feels: the kind that is spontaneous, from within, seeking nothing more than sexual relief. But women are different from men. Context matters much more. The costs and benefits are different. And we should not confuse the response of the vagina and its extended capacity to engage in sex with the sexual response of the sperm-delivery mechanism that is the erect penis.
     Perhaps the mystery of lost libidos is less of a mystery when we think about the situations and mechanisms involved in the evolution of female sexuality. Evidence from our primate cousins suggests a natural, adaptive complexity to female sexual behaviour, and that rather than a genital response to all things sexual it is more of a “maybe” becoming a “yes” or a “no” depending on the situation. And perhaps we should at least show some appreciation of women’s evolved sexuality rather than viewing it so often as a befuddled poor relation of simple male sexuality – or as something broken that needs to be fixed.

Monkeying About with Daniel Bergner

Daniel Bergner’s “What do Women Want” presents some thought-provoking, if limited, information about female sexuality. It challenges the idea that female sexuality is more about making babies than enjoying sex, and promotes instead a picture of a naturally insatiable female sexual appetite that should leave men quaking in their boxers. The evidence from our primate cousins comes mostly from feisty, female rhesus macaque ‘Deidrah’, and her aggressive, ground-tapping, sexual stalking of males. What’s more, we are told, these males have to be replaced every three years because the females grow sexually bored with them. If monkey females behave like this then surely it can only be human culture that has stifled a similar expression of sexual appetite in the human female.
    I spend most of my life learning about the sexual behaviour of other species and, like Bergner, I too would like this information to get across to more people. I’d like to imagine readers of this book rushing out to discover more about other species and the evolution of sexual behaviours. Somehow I doubt it. More likely, these few details are all they will ever know about the rhesus macaque yet this will not stop them using this limited knowledge to point to what it is that women really want. So here I’m going to deal with some monkey business that is clearly passing under the radar.

    The demanding sexual behaviour of Deidrah occurs only when she is ovulating; the rest of the time she avoids males. The rhesus female in natural conditions can conceive once a year during the mating season which lasts only a few months. Outside of oestrus and for most of the year there is no sex. This is clearly about making babies, and it includes a lot of competition between females as they act to out-reproduce each other. Oestrous females are attacked by other females and by males. The sexually assertive behaviour of these female monkeys when they are fertile is the way sex happens in spite of the social disruption it causes to their relations with other females and in spite of the attacks they receive. There is no great motivation to have sex if reproductive success is not on the cards.
    Now, if a human puts a rhesus female and male together in a cage, mating will occur across the female’s cycle: the sex is initiated by the male and the female is receptive (the male is bigger with much more dangerous canine teeth, and she has nowhere to go). Studies across species have shown that when the female controls when a male has access to her there’s a lot less sex than when the male has control. This, incidentally, makes me think about the Mosuo where women do have more control, where there is not the constant presence of a husband, and where a lot less sex seems to go on (as I discussed in Sex at Dusk, though even the Mosuo shame a woman who pursues a man as behaving like “a sow in heat”.)
    Many species are physically not capable of sex outside of the female’s fertile period but not primates, many of whom will have sex at other times whether to confuse paternity, to access food, or to avoid the harm a refusal might entail. A lot has been made of the possible whys and wherefores of the (supposedly) constant sexual receptivity of the human female (and I’m not going to even attempt to deal with this now) but if we are going to hold Deidrah up as an example of natural primate female sexual behaviour then we cannot ignore her lack of interest in sex, or her sometimes passive sexual receptivity, when she is not fertile. For a forager female human ancestor we’d be looking at an interest in sex for a few days during a few months every three years or so, and that’s not a lot of sex!
    Human females are clearly far more willing and able than this. On the other hand, the ‘problem’ of the low female libido that needs to be ‘fixed’ with a ‘female viagra’ is likely, at least in part, to be connected to the expectation that human female sexual desire, as opposed to her physical capacity to engage in sex, should be as constant as that of the male. (This also points to possible clues about what is going on with the apparent disconnect between women’s measured physical responses to sexual cues and the lack of sexual desire that is felt and reported.)
    Back to the rhesus monkeys, there is another issue that will have passed readers by, and this concerns the replacement of males. These monkeys, like most monkeys, live in groups where females stay in their birth group and males move to new groups to breed. (It should also be noted that rhesus males are not passive as is implied in “What Do Women Want” – there is also competition between males, and the male mortality rate peaks during the mating season when males are trying to gain entry to groups and to mate once there.) Females lose sexual interest in resident males after three to five years and the males move on. But female rhesus monkeys reach sexual maturity at the age of three to four years. It is hardly a coincidence that these females are replacing ‘dads’ with novel males and therefore are avoiding inbreeding.
    As I explained at some length in Sex at Dusk, apes do not have this female philopatry with females staying in their birth groups and breeding with transient males. In chimpanzees and bonobos the males stay for life in their birth group and natal females move to a new group at puberty. What’s more, we don’t find a mirror image of monkey female philopatry – there is no loss of sexual interest in familiar females (in fact, older, experienced females are preferred because their offspring have better prospects of survival).
    We can easily see why there is this difference: the immigrant ape females left their fathers behind in their birth group and know their sons in their breeding group. The problem of inbreeding does not occur when females are the immigrants and so they can stay for life in their initial choice of breeding group. It’s about adding more females, not replacing a small number. The reproductive differences between the sexes make male philopatry a whole different kettle of fish from female philopatry – and male philopatry is almost certainly an aspect of ape evolution that we share.

    A lustful and assertive sexual behaviour is undoubtedly one part of the primate female’s sexual behaviour repertoire, as is competition with other females, and a multitude of strategies to achieve infant survival in complex societies. We can look at Deidrah and ask why human female sexual behaviour is not so obviously and aggressively demanding but we then need to understand the context of her behaviour and cannot simply conclude that the differences are solely a consequence of an unnatural and repressive culture.

My name is Lynn Saxon...

and I wrote Sex at Dusk: Lifting the Shiny Wrapping from Sex at Dawn. That might seem an unnecessary statement considering that this is an author blog but there have been rumours that it is not my real name and that I don’t exist. It is and I do.
    The best way to grasp my reasons for writing “Sex at Dusk” it is to read it, as many people have now done. Some of those readers already had their own doubts about “Sex at Dawn” so for them it was just a case of having its many shortcomings clearly stated. But other readers had been so convinced by “Dawn” that they had been actively spreading the word and even gifting copies of the book to others. Some feel cheated, lied to, and angry. I’ll give an extended example to help understand why.
    Imagine you are writing a book about human sexuality and reading about a different culture, say the Mehinaku [1]. As the title – Anxious Pleasures – suggests, the author states that much of the book describes the antagonistic character of men’s and women’s relationships.
    The author of Anxious Pleasures estimates that there were 88 extramarital affairs going on amongst the 37 adults though actual sexual encounters are modest in frequency, limited by long taboos associated with rituals and the life cycle, by the absence of privacy, by competition from jealous husbands and more attractive rivals, and especially by the difficulty of finding a willing female partner. Several of the young men say they are able to have sex on a once-a-day basis but the author writes that “the frequency of sex for the average Mehinaku, however, is far less”.
    He briefly mentions that he believes the affairs contribute to village cohesion and promote enduring relationships based on mutual affection. Three of the 17 women account for nearly 40% of the total number of liaisons (three others have no lover and excite no sexual interest, while even the most unattractive men can obtain a sexual encounter through offering a gift). One of the three most sexually active women had joined the village with her children after abandoning her husband, and she and her children were initially treated poorly. Through sex with many men she was able to obtain fish and protection for her family, and the author writes that her case “suggests that the pressures and incentives for a woman to engage in extramarital affairs sometimes leave her very vulnerable to the men’s advances”.
    The rest of the book documents the ambivalence of men’s and women’s relationships. You read that the sexuality of females is linked to their inferiority and the disgust with their bodies and menstrual blood. Sex is brief and rarely with any foreplay, and orgasm for women is unlikely. The Mehinaku men use the term ‘stingy with their genitals’ about the women as many of the men are constantly sexually frustrated and often have to exchange gifts for sex. Husbands and wives are sexually jealous and affairs are fraught with danger, and life is full of sexual gossip and intrigue. Promiscuity for a woman is seen as potentially dangerous and may lead to the birth of twins or some other abnormality, in which case the infant or infants are buried alive.
     The author also writes that the Mehinaku are one of a number of tribes in this region where the men have sacred flutes and the women are gang-raped, or threatened with gang rape, should they set eyes on these flutes. Their mythology is one of an original matriarchy, the men having seized power from the women. Since then women have been kept in their inferior place with gang rape as one threatened punishment for not accepting male rule. He writes that the women are fearful of the men and their potential violence, and even have nightmares about it. There is also a thin line between consensual and forced sex as the man often takes the woman by the wrist and she is “dragged off” for sex, the term for this ‘dragging off’ being the same term as that for rape by an individual man (there is a different term for gang rape). The author says: “the system is maintained by the threat of phallic aggression”.
    There is general intimidation of women and the author writes that “in the battle of the sexes, women are the losers”. He writes about the constant sexual frustration of men that permeates their relationships and institutions, and about many of the similarities between Mehinaku and American culture though “the Mehinaku pattern of masculinity is more exaggerated than our own”.
    So, what do you decide to take from this? Under what circumstances would you do as Ryan and Jethá have done and choose to quote only the estimation of 88 extramarital affairs going on amongst the 37 adults and the association of this with village cohesion? Under what circumstances would you go on to use this strategy of screening out any sign of sexual conflict repeatedly throughout your own book? It is clearly neither accidental nor unintentional. One reason might be to enable you to make many jokes such as a jokey and false assertion that these women “vocalize” during sex as a way to invite other men to join in (none of the Amazonian women quoted in “Dawn” do this – and nor do women in the other cultures mentioned).
    This is a lack of respect for the sources used. It is a lack of respect for readers. And it is a lack of respect for these peoples whose lives are reduced to saucy titbits for the amusement – and self-interested sexual agendas – of modern, privileged Westerners.
    And it certainly isn’t science.
    Does it matter? Yes it does, because letting this kind of book with its misleading and sanitised stories (and its clear errors) pass unchallenged enables them to spread and to become established as ‘facts’ that people come to know. They spread not only by word of mouth as readers tell friends and family but also, more disturbingly, they get into more books and are even cited in academic papers [2],[3]. (“Dawn” is even picked out as recommended reading in one of these [2].)
    David Ley calls “Sex at Dawn” a “delightful book” in his 2012 book The Myth of Sex Addiction [4]. Citing “Dawn” he writes about Melanesian Islanders where women viewed their husbands’ concubines with pride as they were reflective of his high status, and he writes how “European and colonial laws against infidelity soon stopped this practice, to the lament of many of the men of the island”.
     In “Dusk” I have filled in some important gaps in this story which I have already repeated in my previous blog Sex and Science. Ryan and Jethá, and now Ley, are right that these men miss their concubines. As Davenport actually says [5]: “In brief, men with social positions of consequence and past their physical prime did, and still do, desire to have women over whom they could exercise absolute authority; on whom they could heap material favors – young women who could remain uncalloused by hard work, and whom they could possess sexually, yet cast off when passion declined or when an opportunity for profit appeared”.
    What’s more, it was not European laws against infidelity that stopped this practice. Davenport writes that these islanders had their own severe sanctions against sex outside marriage (other than with these owned concubines) and that: “Social efforts to forestall, to discover, and to punish proven sex offenders [“fornicators” and “adulterers”] are far more vigorous than any that occur even among the most Puritanical segments of our own society... Only murder carries a more severe punishment.” It was, in fact, colonial laws against prostitution that stopped the practice. The elder owners of concubines were allowing young men to have sex with the women in exchange for the European trade goods these young men had accumulated while working away on plantations. As Davenport says, when this law came in the men, being astute traders, sold their concubines to poorer men in other districts and thus suffered little financial loss.
    In our efforts to be ‘sex positive’ we are in constant danger of falling for whitewashed stories about human sexuality that deny the full and complex – and often negative – reality of sex. As Professor Tim Birkhead writes in the preface of his excellent book on sperm competition Promiscuity [6]: “the very fact that sex is so important to us means that we are vulnerable to being exploited by it. This, in turn, means that it is important that we understand it – and particularly from an evolutionary perspective.”
    I believe that being ‘sex positive’ is about people having access to full and honest information about sex, and so I wrote Sex at Dusk: Lifting the Shiny Wrapping from Sex at Dawn.




1     Gregor, T. (1985). Anxious Pleasures: The Sexual Lives of an Amazonian People. Chicago: University of Chicago Press.

2    Conley, T. D., et al. (2011). Women, Men, and the Bedroom: Methodological and Conceptual Insights That Narrow, Reframe, and Eliminate Gender Differences in Sexuality. Current Directions in Psychological Science, 20(5): 296-300.

3     Conley, T. D., et al. (2013). A Critical Examination of Popular Assumptions About the Benefits and Outcomes of Monogamous Relationships. Personality and Social Psychology Review, 17(2): 124-141.

4    Ley, David J. (2012). The Myth of Sex Addiction. Lanham, MD: Rowman & Littlefield.

5     Davenport, W. H. (1965). Sexual patterns and their regulation in a society of the southwest Pacific. In F. A. Beach (Ed.), Sex and behaviour. New York: John Wiley & Sons.

6    Birkhead, T. R. (2000). Promiscuity: an evolutionary history of sperm competition. Cambridge, MA: Harvard University Press.

Sex and Science

I know a lot about ‘the birds and the bees’. I know, for instance, about the carnage in one species of bee due to male sexual competition; about the harmful sexual harassment that females experience in another; and about the honey bee male that wins in the nuptial flight only to have his phallus explode inside the queen, ripping out his innards as he drops dead.
As for birds, I know that gang rape attempts are quite common in mallard ducks and that females sometimes drown as a consequence. Waterfowl males, unlike most other bird species, possess a ‘penis’ – tissue from the cloaca is everted to form a spiralling, grooved structure. The female reproductive tract spirals in the opposite direction and can block the progress of sperm from the unwanted males. This is sexual conflict – and it is as natural as cooperation.

Many people believe that because sex is ‘natural’ it must be ‘naturally’ problem-free. They might have a more general awareness that it is a mistake to simply conflate what is natural with what is desirable or beneficial (malaria, for example, is natural) but this thinking tends to disappear when it comes to sex. Sex equals pleasure, period. Birds do it, bees do it, so let’s do it – it’s only natural.
But for those of us more familiar with evolution and the sexual behaviours of other species, we know that sex often includes some form of conflict. This presents a problem in that any attempt to show the reality of natural sexual conflicts is likely to be dismissed or attacked as supporting some kind of religious or political ‘sex-negative’ agenda.
Add to this the fact that sex is how genes ‘out-do’ other genes to get into new generations and spread through populations, and we can expect arguments about sex to be greatly influenced by conscious and unconscious self-interest.
A good, objective understanding of the reality of sex turns out to be up against obstacles from many directions.

Do we need to know about other species to understand human sexuality? I believe that we do, not least because we need to understand evolution to understand how we came to be what we are. Unfortunately, using evolutionary arguments along with examples from the sex lives of other species also brings its own problems, and the void that is created as we let go of religious myths can be too easily filled with pseudoscience. Science is very much a work in progress, and as new evidence is discovered new hypotheses can be tested and theories can be supported or challenged. But sometimes ideas that are not supported by evidence spread unchallenged, and that’s where the main problem lies.

One example of this is the book Sex at Dawn by Christopher Ryan and Cacilda Jethá. Their argument is that before ten thousand years ago our ancestors’ natural state was like that of the popular view of the bonobo where sex, like food, was shared. The authors took the fact that monogamy is not ‘natural’ and they constructed an argument that our natural sexuality is one of relaxed, conflict free, promiscuity, further arguing that going against this ‘natural’ sexuality is what has led to pretty much all of our personal and social ills today.

There is nothing inherently wrong in proposing a hypothesis that our ancestors, pre-agriculture, had multiple on-going sexual relationships with little or no sexual jealousy, no nuclear family structures, and no concern about paternity. Many readers were easily convinced by what appeared to be sound, scientific references as evidence, so I decided to check that evidence – often coming from sources already familiar to me – and time and time again it failed to stand up to scrutiny.
The evidence failed throughout the book but as people tend to be much more interested in humans than other species I will give just three, brief examples (from dozens) to show how other cultures are falsely portrayed to support an agenda of a naturally relaxed and promiscuous human sexuality, where everything – food, sex, childcare – is shared. The corrected information I provide is not from other, contrary sources but from the very same sources used by the authors.

The Aché, Ryan and Jethá write, can change a spouse with relative ease. This is part of the authors’ attempt to show how marriage is not taken so seriously in other cultures. They do not tell the reader that to be without a husband means a mother might as well kill her own children (and others are not averse to doing the killing) because their prospects for survival are so poor. Aché children whose parents divorced have been shown to be three times more likely to be killed than if the marriage endured. This is one of many ‘partible paternity’ societies in the Amazon which are presented in a way that does not honestly reflect the reality.

The Siriono are given as evidence for limited sexual jealousy as well as for our natural egalitarian and sharing nature. Ryan and Jethá omit to tell the reader that (as their source, Holmberg, writes) these people are near-starving and always hungry with many quarrels over food and its allotment, hoarding, and the reluctance to share. The nuclear family is the fundamental social and economic unit, there is a sexual division of labour, and women are subservient to men. Most marriages are monogamous but the higher status better hunter males have more than one wife. If the wives are sisters, as they most often are in the polygynous marriages, there is less jealousy than when not. The wife with whom the husband has the most sex gets the most meat so the wives frequently vie with each other for his sexual favours.
In quarrels over sex, men channel their aggression towards adulterous wives, and women channel theirs towards the women who have caused their husband to err; women are therefore believed to be the cause of most sexual disputes. Food is the best means men have to obtain extra-marital sex, using game to seduce a woman who otherwise might not yield to his demands.
Sex is usually in the privacy of the bush and is a rapid and violent affair with few preliminaries: no kissing but there can be scratching and biting. If a man is alone with a woman in the forest he may roughly throw her to the ground and have sex without a word being spoken. Once a girl has gone through puberty rites, which can happen before she has actually reached puberty, she can be married; any sex with her cannot be seen as rape because ‘rape’ can only be applied to sex with a girl who has not gone through the puberty rites.

Ryan and Jethá tell the reader about anthropologist William Davenport who lived among Melanesian islanders in the 1960s. Until colonial laws stopped the practice, they tell us that these people avoided monotony by allowing men to have young lovers. Wives were not jealous of these concubines but regarded them as status symbols. As with the other two examples, we can look at what Ryan and Jethá’s very own source for their information says:
The acquisition of concubines was only open to older, well-established men. The cost of the concubines, who were imported from another island, was ten times the amount paid for a wife and beyond what most individuals could afford so a group of five to ten men of the same ‘men’s house’ would buy one collectively, and one of the men had authority over the concubine and how she was shared. The concubine’s social status was really that of a domestic slave: she had no authority over any children she bore and she could be legally sold or even killed by her principal owner. This is why the brideprice was so high. A normal brideprice signified only partial transfer of rights over a wife from her kin to her husband’s kin, but the purchase of a concubine meant absolute severance of all her family relations and she was even given a new name from a stock of personal names reserved for concubines.
The concubine was also a prostitute and sometimes could represent a sound investment as she could be sold on a night-by-night basis to men from other men’s houses. Sometimes she might even be sold to another men’s house for a profit, or she might just be sold on when the men tired of her and they would then begin to negotiate for a new one. As they grew old, concubines were sold to less prosperous districts and finally given as wives for a normal brideprice. Sometimes concubines served the purpose of a sexual outlet for unmarried sons to prevent them having affairs with single or married women which would lead to serious legal tangles.
Again this paints a very different picture from the severely edited version presented by Ryan and Jethá. They are right that these men miss their concubines. As their source says, they miss having “women over whom they could exercise absolute authority; on whom they could heap material favors – young women who could remain uncalloused by hard work, and whom they could possess sexually, yet cast off when passion declined or when an opportunity for profit appeared”.

These are just a few examples of the way evidence has been treated throughout Sex at Dawn, which also includes a number of straightforward errors. It is not science. Unfortunately many readers think that it is, including a few academics (at least in psychology) who are now citing this book in their own work.
Agenda-driven pseudoscience is frustrating and disappointing. The attitude of the authors appears to be that there is nothing wrong in what they have done because it is, they argue, what everyone does. It is enough of a concern when general readers are taken in by ‘deceit by omission’ and such disrespect for science and available information but when academics have also been hoodwinked then we have an even more serious problem.