Fifty Shades of Apes

Data indicates that women are inclined towards violent pornography, violent sexual fantasies and real-life sexual domination. In our ape ancestors, such preferences probably made sense.

Five silhouettes of primates: Gibbon, human, chimpanzee, western gorilla and Sumatran orangutan, Wikimedia Commons 

Aella's big sex survey showed that women are more into violent porn than men. In the survey, women more than men reported that they prefer depictions of violence and non-consent. That should be no surprise - decades of research have persistently shown such a pattern. Scattered, underfunded research indeed. But still research. 

First and foremost, we have Seth-Stephen Davidowitz, author of Everybody Lies (2017). Davidowitz cooperated with PornHub, which had one surprising result to share: When female users of PornHub made searches, 25 percent of the times they explicitly wrote a wish to see a video of a woman being subjected to pain or humiliation. 5 percent of searches made by female users contained the word rape, although PornHub bans such content. Less than half the share of male users asked for women in distress. Only 2 percent of them explicitly searched for rape videos.¹²

One could assume that only women with the hardcore preferences go to PornHub, while ordinary women go to sweet romance literature. But also the romance literature features its fair share of sexual violence, or did before political correctness sanitized away much of that. A 1987 review by Carol Thurston showed that in the 1970s, half of romance books featured the rape of the heroine, not seldom by the hero himself³⁴. For example, the book The Flame and the Flower (1972), features a young penniless woman in the 19th century who escapes a rape attempt through killing her assailant. She runs away from the murder scene and ends up on a ship, where she gets raped by the captain. Not once, but three times in a row with some sleep in between. On the captain's fourth rape attempt, she manages to escape. She becomes pregnant from the rapes and the captain is forced to marry her. None of them is happy with the situation. After a bookful of murderous intrigues, however, the heroine is about to get raped by a villain and her husband saves her. They then live together happily ever after.⁵

A meta-study specifically about women’s rape fantasies concluded that sexual fantasies about rape-situations are very common among women. Between 31 and 57 percent of the women in the studies had those kinds of fantasies. For between 9 and 17 percent of women, rape fantasies either occurred frequently or were their preferred fantasies.

“Because rape fantasies are perceived as socially unacceptable or potentially embarrassing, these are most likely underestimates. Although rape fantasies are not the most prevalent or most frequent sexual fantasies, they are among the most popular, and they play a major role in the fantasy lives of one or two women in 10, ”

Joseph Critelli and Jennie Bivona, authors of the study, write.⁶

A study by psychologists Kelly Suschinsky and Martin LaLumiere measured men's and women's rates of erection and vaginal lubrication respectively while they listened to 90-second stories told by a woman. The stories featured different combinations of violence and sex, consent and non-consent. The male study participants showed a clear pattern. They were the most physically aroused by hearing about a consensual and non-violent sexual encounter. The violent or non-consensual situations gave them weaker erections, on average. Among the female study participants, there was no such pattern. An account of violent, consensual sex, made women almost exactly as physically aroused as an account of non-violent, consensual sex. Hearing about a violent case of rape made the female study participants only slightly less physically aroused than hearing about consensual sex. Violence alone made neither sex notably sexually aroused. When the study participants listened to an account of a violent, but non-sexual situation, their physical signs of sexual arousal was as low as when they listened to an explicitly neutral account. Both sexes reported that they found narratives involving violence or nonconsent to be highly unpleasant and somewhat anxiety provoking.⁷

It has been proposed that lubrication in connection to rape scenes is just an ancient defense strategy against injury. If you will get raped anyway, then it is better to get lubricated in order to avoid physical damage and infection. That is certainly a possibility. But the studies of women's sexual fantasies and choices of pornography suggests something else too. Writing “rape” in the search window of a pornography site is not defensive behaviour. It's an active choice. Choosing the romance book where the heroine gets raped by the hero instead of a tamer book is also an active choice. If women liked another book better, that book would have become the bestseller instead. 

S and M

As far as my information goes, romance books are no longer filled with rape scenes. Instead a more politically correct practice has somewhat taken its place: BDSM. 

The highest grossing film with full restrictions in American film history was Fifty Shades of Grey. The film was based on a hugely successful romance novel about a BDSM relationship where 22-year-old virgin Anastasia Steele submits to the handsome and very successful 27-year-old entrepreneur Christian Grey. For some unexplained reason Christian Grey falls madly in love with Anastasia, and she reluctantly accepts Christian’s sexual sadism. The book sold 125 millions copies.  

I have tried, and failed, to find any reliable numbers of the demography of BDSM contact sites like Fetlife. However, Aella's survey is very clear on who finds dominating and being dominated sexually arousing: Females disproportionately answered they felt aroused by being submissive in sexual interactions. 

Males disproportionately answered that they were feeling aroused by being dominant in sexual interactions. 

Graphs borrowed from Aella's post How Fetishes Differ By Region and Gender 

Interestingly, males were not as aroused by dominating as women were by submitting. And males who feel aroused from submitting sexually seem to have a hard time finding a woman who enjoys dominating them. It all fits in with what I have heard and read anecdotally, although I can't easily find any additional qualitative data that confirms it. 

Love kills lust

A less sensational, but still a bit surprising finding is that women tend to get sexually aroused by the thought of sexual novelty. There is strong evidence that women prefer committed relationships to shorter, less stable unions. Most of all, the findings about how sex ratios change realities point in that direction: When there are more males than females, stable relationships tend to be the norm. When there are more females than males, casual sexual relationships tend to be the norm. That, if anything, proves that females have a general wish for committed relationships. As soon as the numbers are on their side, that is what they use their power for.⁸

That doesn't necessarily mean that females get the most sexually aroused from thinking about stable, loving relationships. Psychologist Meredith Chivers measured women's rates of vaginal lubrication while she played 90 second sound clips of different seduction situations. Friends, total strangers and long-term lovers of both sexes made up the seducers. Women's physical arousal was most significant at the clips with total strangers. Long-term lovers were also rather physically arousing and friends were not physically arousing at all. The sex of the seducer didn't matter for the physical arousal of the study participants.⁹

Also in real life, women seem to find long-term lovers less sexually arousing. Both men and women tend to become less interested in sex in a stable relationship. But the effect is much more significant for women. It even seems that among younger people, only women lose interest in sex as a relationship grows longer. In one study almost two thousand students between 19 and 32 years old were asked about their relationship satisfaction. By the time of the study, all the participants were in stable heterosexual relationships. Both males and females were less satisfied with their sexual lives after being in the same relationship for a number of years. But only women reported less interest in sex. Men remained as interested in sex regardless of how long they had been with the same woman.¹⁰ Another, smaller study, shows the same results: Being in a long-time relationship decreased young women's, but not young men's interest in sex.¹¹

It is commonly taken for granted that while men can separate sex and love, women need a good relationship to enjoy sex. It seems like reality is not that simple. A study investigated how sexual satisfaction is linked with the quality of a relationship in general. The study found a positive correlation. But the correlation was much more positive for males than for females. That is, for men a good relationship was strongly positively related to good sex. For women, the two phenomena were much less related.¹² That is, a good relationship doesn't automatically lead to good sex for women. And good sex doesn't necessarily lead to a good relationship. 

Psychologists Marta Meana and Karen Sims interviewed 19 happily married women who had lost their sexual desire. They concluded the following:

"Despite self-reportedly happy marriages, they frequently referred to the excitement sparked from the attention of other men. Some felt certain that their desire would return if they experienced a new partner. We have long associated the link between sexual excitement and novelty to men’s sexual desire, but rarely do we associate it to women’s desire. In our sample, closeness had led to familiarity which had too often led to efficient but boring sex. Although lack of romance was often cited as a cause for declines in desire, romance referred back to behavior associated with a time when they barely knew their husbands—when the relationship was very young."¹³

Where women have the power to decide, in most cases they decide that men and women should form long-term couples. Still, it seems like men function better sexually in the situations that women nudge them into than the women themselves. It is easier for them to translate a good relationship into sexual desire and sexual pleasure, or, alternatively, to think that a relationship where the sex-life is good is a good relationship. It was traditionally thought that men most strongly said yes to casual sex and women to relational sex. But it rather seems like men say yes to sex in general: Temporary liaison? Yes please. Sex with long-term girlfriend? Yes please. Anything goes, it seems, as long as relationships are reasonably good. Women, on the other hand, seem curiously fussy. They don't like hook-ups nearly as much as men, but also fail to thrive sexually in long-term marriages at higher rates than men.

But why? 

The only way to solve this contradiction is, I think, to describe sexuality as consisting of two components: Desire and inhibitions. I wrote a blog post about that a while ago. I think it is entirely possible to sexually desire something without wanting it. Sexual arousal is not will. It is entirely possible for people to feel sexually aroused by a thought without wanting to carry it through. Indeed, it is entirely possible to feel sexually aroused by a thought without even liking the thought in itself.

For example, I think it is crystal clear that women don't want to get raped. As psychologist David Buss explained in When Men Behave Badly (2021), women pay a rather high price to increase their level of safety against unwanted sexual attention.¹⁴

According to David Buss, male violence against female partners can be an evolutionary strategy for males to gain advantages at the expense of females. Males who batter, threaten and diminish their partners tend to do so in order to keep a partner of higher mate value than themselves. If a woman discovers that she can get a better partner elsewhere, she will be tempted to leave. In such situations, violence is a male strategy to hold on to a female partner who can never be replaced with another partner of equal value. Women have very good reasons to try to avoid men who coerce them into such sub-market deals. Especially as that kind of coercion can be lethal: Men regularly feel that they prefer to murder a partner rather than letting someone else have her.¹⁵ 

We have very good reasons to assume that women don't like it when their partners become violent toward them, that they want to choose their own sexual partners and that they mostly want stable, emotionally secure relationships. There simply is a rather wide gap between what a vast majority of women want and what makes at least a significant minority of women sexually excited. The question is: What caused that gap? It is easy to see why women want to choose their own nice, generous and non-violent partners. It is much more difficult to understand why thinking about the total opposite causes a significant proportion of women to be sexually aroused.

There have been many "excuses" for women's tendencies to get sexually aroused from thoughts of sexual violence. The most common is probably that women fantasize about rape because that relieves them of responsibility for being sexual. I think that explanation doesn't hold, because then fantasies of rape and sexual violence would have decreased as female sexuality became increasingly celebrated. Also, most women don't frequent PornHub. Those who do probably aren't the most shy about their sexuality. It is unlikely that women go to PornHub and type "rape" in the search window because they are so shy.

Then there is the general theory that females desire violent males because violent males were better at protecting and providing for them. That is not an entirely bad theory. But it fails to explain one detail: Why would females like males who are violent to them? According to David Buss' book, habitual wife beaters are most of all losers who realize they can't retain their partners with peaceful means. Such men are certainly nothing to strive for.

Normally, the function of sexual desire is to make an organism seek the desired quality out. Men tend to sexually desire youthfulness and sexual variety because seeking out different youthful women paid off evolutionarily. A significant share of women sexually desire situations with men who are violent and take them by force because… because… Yes, why would seeking such men out ever be a good idea?

In the beginning were apes

I think the only way to make sense of this, is to go very far back in time. In human society, it makes sense to look for a male who is high-investing, protective and capable. In the ape society that preceded human society, however, things were very different.

Nothing can be said about those ancestors for sure, because we don't know who they were. We can only make educated guesses. And primatologist Richard Wrangham (a very educated man indeed) can help us.

In his book Demonic Males (1997), Wrangham explains that about five million years ago, there were neither humans, nor chimpanzees or bonobo chimpanzees. There was only one ancient common ancestor. About 13 million years ago, there were also no gorillas. Only a common ancestor of gorillas, chimpanzees and humans. About 16 million years ago, that common ancestor also included orangutans.¹⁶

We don't know what the common ancestor looked like. Not 13 million years ago, not 5 million years ago. No fossils that can reliably be attributed to the common ancestor have been found. We know even less about how it behaved. We can only make educated guesses from how our closest relatives behave today.

Richard Wrangham argues that the chimpanzee is a very good model for the common ancestor. The chimpanzee has had five million years to develop since the ancestors of humans and chimpanzees took different genetic paths. Still, it probably developed much less than humans. Its physical likeness with the gorilla is a sign of that. Chimpanzees and gorillas have been different species for roughly 13 million years. Still, they look much more similar to each other than to humans. Even experts of apes have had difficulties discerning small gorillas from large chimpanzees¹⁷. In spite of this superficial similarity, humans and chimpanzees are more closely genetically related than chimpanzees and gorillas.  

The first known ancestor to humans is Ardipithecus ramidus, who lived about 4.4 million years ago. It was very similar to a chimpanzee. So similar that some experts think that it should be classified as a chimpanzee. (Richard Wrangham and Dale Peterson, Demonic Males, 1997, 45) Also the renowned Lucy, who was from the species Australopithecus afarensis and lived between 3 and 3.8 million years ago, was something of a mixture of a chimpanzee and a current human: Human legs and pelvis, combined with the upper body and skull of an ape.¹⁸

The fact that our common ancestor five million years ago looked like a chimpanzee doesn't mean that it must have behaved like a chimpanzee. But it can also not be excluded that the behavior of chimpanzees has been as stable as their physical appearance. Sadly, our closest relative in nature is not always very nice. It is social, but competition for the places on top of the hierarchy is literally murderous. Full-scale wars rage between groups of chimpanzees. Small groups of males, and an occasional female, perform raids into other groups’ territories. If they find an unprotected individual, especially if it is a male, they assault him with mortal wounds.¹⁹ Males kill infants they suspect that they have not fathered, if they can.²⁰ High-ranking females also sometimes kill other females' infants.²¹

Ape patriarchy

Chimpanzee females are more or less always submissive to males. That is not surprising, as males are about 20 percent bigger. Males cultivate strong bonds with each other. They are bitter contestants for the alpha position within their groups, but they are also allies in war against other groups. They can also form alliances in their struggle for the alpha position. They are to a large extent close genetic relatives, since they stay in the group where they were born.²²

Females, by contrast, migrate to other groups in their early teens. By that time they get a genital swelling that signals fertility and simplifies the life-threatening journey to a rivaling group.²³ The females are, in other words, strangers in their flock. They create no strong bonds with each other, but live rather lonely with their children. That is probably because they can't afford living too closely together, because quite big areas are required to provide for a female with her children. A female with a nursing child also needs to distance herself from bigger groups of chimpanzees in order to avoid infanticidal males. (Frans de Waal and Frans Lanting, Bonobo - The Forgotten Ape, 1997, 122) Females in certain groups do socialize. But the above mentioned circumstances prevent them from living close enough to create really trusting relationships. In captivity, females have been observed forming supporting coalitions against male aggression. In the wild, such opportunities are limited.²⁴

It can't be said with any certainty that the common ancestor’s social life was similar to the chimpanzee’s. But it would be a strange coincidence if the ancestor of both chimpanzees, gorillas and humans lacked properties that all three species have in common. For example, it would be strange if male dominance was developed separately by gorillas, chimpanzees and humans. With a few exceptions, male dominance is the rule among primates. For example, gorilla males are almost double the size as females. They live in harems with a few females whom the male dominates totally.²⁵

The infanticide problem

The risk of infanticide is one of the foremost factors that shapes female sexuality among primates. For males of species that hold harems, infanticide is evolutionarily logical. A male who takes over a harem can't count on being able to stay for very long. He doesn't have the time to wait for the females to finish nursing before he can mate with them. By that time another male might already have taken over the harem, and started to kill off the infants of his predecessor.²⁶ Infanticide benefits the individual male, but imposes great costs on females. It can also be detrimental to the species as such. Vulnerable groups of animals are sometimes eradicated after too many take-overs.

For males infanticide is a logical strategy to spread more genes. For females, having their infants killed is hugely costly in evolutionary terms. For that reason, primatologist Sarah Hrdy investigated the hypothesis that the risk of infanticide shapes female behavior: Females should have evolved to minimize the damage from living among murderous males. In general it is very difficult for females to directly defend their infants from infanticidal males. For example, langur females try to defend their own and relatives’ infants, but most often they fail. A female together with her female relatives might be able to save an infant both once and twice. But the male can try again and again until he succeeds.²⁷ Females of different species have developed different adaptive strategies against these kinds of threats. Pregnant female mice can, in some way, sense when an infanticidal male approaches them. The smell of such a male makes them self-induce an abortion through absorbing the embryos they carry.²⁸

Another way for females to adapt is to make it more difficult for males to estimate which infants are actually theirs. This is the main way primates adapted. It is more or less a general rule that males do not kill an infant if they see any chance that they could have fathered it. In general also rather slight chances of paternity are enough for a male to let an infant live. This drives females to a type of behavior that for a long time was viewed as un-femalelike: promiscuity. In order to decrease the risk of infanticide, a female needs to mate with every male who could possibly pose a threat to her infant. Not only within the group, but also males who are sneaking around in the vicinity, ready to challenge for the alpha position.

Our murderous cousins

Among several species of primates, it is very common that a female whose infant has been killed mates with the killer male. Among harem-living animals, she doesn't have much of a choice. If she tries to choose another male, the infant will be killed at birth by the murderous alpha male. If she decides to wait until the harem is overtaken by a nicer alpha male, she might have to forego several years of reproduction. Then her genes would lose out compared to those of less fussy females.²⁹

Also in one of our closest cousins, the gorilla, females habitually mate with the male who killed their child. About one in seven gorilla children will be killed by male gorillas, according to data from primatologist Diane Fossey's observations. That is many enough for the average gorilla female to have an infant killed during her lifetime. Infants are killed by males without harems of their own. When a child is killed by a male, the child's mother tends to choose to become the partner of the killer male. It sounds odd, since gorilla females are very devoted mothers, but there is a certain logic in it. If the female stays with her former partner, her next child will probably also be killed. The killer male has shown his potential, while her current partner has shown that he is in decline. It is better to side with a winner.³⁰

Gorillas systematically kill infants. Infanticide is less common among chimpanzees. But it is a real risk that females need to adapt to. Among other things, females tend to keep away from the group when they give birth and the infant is very small. Researchers seldom see chimpanzees being born, because females tend to go on “maternity leave” from the group. When researchers once observed a female who nonetheless gave birth to an infant in front of several group members, a male immediately grabbed the newborn and started to cannibalize it.³¹

Domestic violence 

Among Gorillas, infanticide is the big conflict between males and females. Gorilla males grab infants from unknown females and kill them whenever they get the chance. But otherwise they treat the females, who are half their own size, rather well.³² Male chimpanzees don't kill infants at such rates. But they oppress females in a complex and deliberate way. In groups of chimpanzees, all males normally dominate all females. When the males think that they need to establish their dominance, they batter the females. It is easy for them, because females are significantly smaller. The systematic battering begins when the males reach the same size as the females, in their early teens. Making all the females of the group submit to oneself is a step on the road to becoming an adult male chimpanzee. The young males beat the females, kick them, pull them to the ground, jump on them. The females seldom get seriously injured. The males’ purpose is not to injure them, but to scare them into submission. The teenage males batter the females until the latter start greeting them with a panting sound that signals submission.³³

Although the battering is most frequent when the male reaches his teens, it forms a part of the relationship between the sexes throughout their lives. Male chimpanzees batter females in order to punish them for supporting their rival for the alpha position, or for making them sexually submissive. Most of all, males try to get a female to take a walk with him during the days she ovulates. The period of ovulation is very stressful for a female, as several males often fight over her. She risks getting hurt herself through being at the center of fighting males. Therefore the female often prefers to walk away with a single male during those days, in order to mate without stress. If she forgets to do this with a certain male, that male might attack and batter her. Then she follows him willingly.³⁴

A theory of masochism

Females are unable to boycott violent males who kill their children. If they do that, they risk losing in competition with other females who are less choosy. They would also have less violent sons themselves, who would be unable to compete with more violent males.³⁵ How ought a female who lives among oppressive males to feel, in order to maximize her reproductive chances? Males from whom she can't escape, but has to relate to.

In the late 1970s, Sarah Hrdy shocked the scientific community by reporting on indiscriminately promiscuous female langurs. Being promiscuous made sense, she argued, because that was a way for females to obscure paternity. The greater the number of males who thought they could be the father to an infant, the safer that infant.

That theory makes sense. It makes so much sense that it has, as far as I know, become largely accepted. Sarah Hrdy herself saw an infanticidal ancestor as a probable reason to why females today harbor promiscuous desires. 

I think the theory makes so much sense that it deserves to be expanded: In order to protect their future children, females surrounded by infanticidal males do not only need to mate with as many males as possible. They also need to mate with as many unpleasant, threatening and dangerous males as possible. Mating with a timid beta male probably won't help much, since he is unlikely to be in the position to kill her child anyway. What counts is seeking out the males with the capacity and mentality to dominate females enough to kill their children.

How does nature achieve this? It might be that females who associate violence with sexual desire are selected for. If a female detects an unusually aggressive and threatening male in her  surroundings, evolutionary logic dictates she should mate with him as soon as possible. The mechanism should be: See violent male → get very horny.

In the case of gorillas, it looks like such a mechanism is at work. There are few more unpleasant things a male gorilla can do to a female gorilla than killing her child. And still, through some psychological mechanism, the female gorilla's reaction when that happens is to join the murderer male and mate with him. We can only guess what is going on in the minds of the gorilla females who choose their children's murderers as their new masters. From the outside, it certainly looks like a fetish for bad boys.

See violent male → get very horny

Our closest cousins, the chimpanzees, have a more complex society than the gorillas. A number of males live together with about equally many females. Infanticide occurs, but not as predictably and regularly as in some harem-living species.

Still, the pattern see violent male → get very horny should apply also to them. To begin with, all chimpanzee males are violent towards females. For a chimpanzee female, at least in certain groups, there is no male who has both never battered her and who is fit to mate with. A female who gets sexually turned off by every male who ever assaulted her would disappear rapidly from the gene pool (provided she can withstand rape attempts). In a group where all males batter the females as a stage of passage, a sexual aversion to violent males doesn't work. So the baseline must be at least a sexual toleration of violent males.

What if one male is unusually aggressive? That could mean that he is an upstart, aiming for the alpha position. In that case females have good reasons to take out an insurance for their future children, would that male eventually rise to the top. Chimpanzee males also don't need to be the highest ranking to commit infanticide. So female chimpanzees have every reason to feel that little extra tinge of horniness when a male shows unusual vigor in his violent outbursts. 

Female chimpanzees seem to have a sexual taste for seeking out danger. For some reason some of them make trips into enemy territory when they ovulate. Those trips are very dangerous - chimpanzees have the bad habit of ganging up and lethally assaulting strangers they meet. Chimpanzees from other groups can be very hostile, also to females.³⁶ Still, females decide to venture into strange territory to breed. No one knows why they do that. Is it to seek out new genes? Is it an act of diplomacy in order to get better treated in case of an attack? What seems clear is that chimpanzee females sometimes choose very dangerous ways to mate. Like if they feel a sexual thrill from taking risks.

Five million years later

We can't know for how long the chimpanzees have behaved like chimpanzees. We can't know whether their behavior has been as stable as their looks. But the general assumption that ape females gain advantages from being a bit masochistic is not only based on the chimpanzee: In every ape, or, for that matter, in every animal where males are violent to females and practice infanticide, a masochistic leaning should pay off among females. The more potentially unpleasant a male is, the greater the reason to desire him. That simple formula applies to all females who live among violent, infanticidal males. 

The question is: Can an instinct remain for five million years, even when circumstances change? Even when it spurs females to make the wrong choices and fall into the arms of men who are outrightly dangerous to them? I would suggest it can. 

Partially because females did indeed develop other preferences that favors high-investing, non-violent men. If you ask females all over the world, they tend to stress that they want a man who treats them well. Anthropologist Napoleon Chagnon didn't get any specific preferences for a husband from his female Yanomamö informants, except one: That he is not too violent (that is, he doesn't inflict wounds to his wife with machetes, bows and arrows or burning lodges, as a certain share of Yanomamö men did).³⁷ Human females in general have a very clear preference for men who provide for them and treat them well. It is just that this preference is not strictly sexual. 

Partially, very old sexual preferences might have survived because women only had limited opportunities to choose when and with whom to have sex. During human history, women have had some freedom to choose their sexual partners. But far from total freedom. In many known human societies, being a reproductively successful woman has been less about making the right choices and more about coping with choices other people make. Putting up with one's own inability to choose might have been at least as important as choosing. Masochistic tendencies can be disastrous for a woman who has the opportunity to choose a man entirely freely. However, for a woman who is stuck with a violent man whether she likes it or not, being a masochist is not obviously something negative.

Most importantly, the transition from ape to human most likely had something to do with instincts becoming less important and intellect becoming more important. Evolution not only favored humans with the right instincts. It also favored humans with higher ability to overrule instincts with reasoning. In other words, we are stuck with some instincts forever. That's the bad news. Since our ancestors once learned to use their intellects to handle certain instincts, we are deemed to continue doing that. The good news is that human intellectual efforts tend to get better with time. The more knowledge we collect of our animal sides, the better we will be at dealing with them.

1. Seth-Stephen Davidowitz, Everybody Lies: Big Data, New Data, and What the Internet Can Tell Us about Who We Really Are, 2017, chapter 4, page 93-94, (I'm a bit insecure over the page numbers here because I recently discovered that page numbers of digital books and physical books tend not to match. It is in the section with a lot of "PornHub" mentions, at 31% of the book)

2. https://www.vox.com/conversations/2017/6/27/15873072/google-porn-addiction-america-everybody-lies

3. Carol Thurston, The Romance Revolution: Erotic Novels for Women and the Quest for a New Sexual Identity, 1987

4. https://www.huffingtonpost.co.uk/suzi-godson/fifty-shades-of-grey_b_6671124.html

5. Wikipedia article about The Flame and the Flower

6. Joseph Critelli and Jennie Bivona. The nature of women’s rape fantasies: An analysis of prevalence, frequency, and contents, 2008, Link Sci-hub link

7. Kelly Suschinsky and Martin LaLumiere, Prepared for anything?: an investigation of female genital arousal in response to rape cues, 2011 Link Sci-hub link

8. See Jon Birger, Date-o-nomics, 2015

9. Meredith Chivers, Amanda Timmers, Effects of Gender and Relationship Context in Audio Narratives on Genital and Subjective Sexual Response in Heterosexual Women and Men, 2012 Link Sci-hub link

10. Dietrich Klusmann, Sexual motivation and the duration of partnership, 2002 https://pubmed.ncbi.nlm.nih.gov/12049023/

11. Sarah Murray, Robin Milhousen 2012, Sexual desire and relationship duration in young men and women Link

12. Susan Sprecher, Sexual satisfaction in premarital relationships: associations with satisfaction, love, commitment, and stability, 2002 Link

13. Marta Meana, Karen Sims, Why Did Passion Wane? A Qualitative Study of Married Women’s Attributions for Declines in Sexual Desire, 2010 Link Sci-hub link 

14. David Buss, When Men Behave Badly, 2021

15. David Buss, When Men Behave Badly, 2021, chapter 5 and 6

16. Richard Wrangham and Dale Peterson, Demonic Males, 1997, page 42

17. Richard Wrangham and Dale Peterson, Demonic Males, 1997, page 43-48

18. Richard Wrangham and Dale Peterson, Demonic Males, 1997, page 31

19. Richard Wrangham and Dale Peterson, Demonic Males, 1997, page 5-21

20. Sarah Hrdy, Mother Nature, 1999, page 86

21. Sarah Hrdy, Mother Nature, 1999, page 52

22. Richard Wrangham and Dale Peterson, Demonic Males, 1997, page 24

23. Sarah Hrdy, Mother Nature, 1999, page 185

24. Richard Wrangham and Dale Peterson, Demonic Males, 1997, page 226-227

25. Richard Wrangham and Dale Peterson, Demonic Males, 1997, page 147

26. Sarah Hrdy, Mother Nature, 1999, page 33

27. Sarah Hrdy, Mother Nature, 1999, page 33

28. Sarah Hrdy, Mother Nature, 1999, page 90

29. Sarah Hrdy, Mother Nature, 1999, page 33

30. Richard Wrangham and Dale Peterson, Demonic Males, 1997, page 151

31. Hitonaru Nishie, Michio Nakamura, A newborn infant chimpanzee snatched and cannibalized immediately after birth: Implications for "maternity leave" in wild chimpanzee, 2018 Link Sci-hub link 

32. Richard Wrangham and Dale Peterson, Demonic Males, 1997, page 146-151

33. Richard Wrangham and Dale Peterson, Demonic Males, 1997, page 143-146

34. Richard Wrangham and Dale Peterson, Demonic Males, 1997, page 144-145

35. Sarah Hrdy, Mother Nature, 1999, page 33

36. Sarah Hrdy, Mother Nature, 1999, page 85

37. Napoleon Chagnon, Noble Savages, 2013, chapter 8, 42 % (I recently discovered that my e-book program shows incorrect page numbers, so I use the more fool-proof method of citing percents of those books instead)