Sex At Dusk v. Dawn

Two years ago I was persuaded by the book Sex At Dawn, at least on its “key claim, that forager females were sexually promiscuous.” While I didn’t buy authors’ free-love scenario, I thought our ancestors were much less tied to their sex partners than most folks realize:

A Hadza man hunts big game to look sexy, even though that retrieves less food. Except that when a women he has sex with has a kid he thinks is his, he’ll gather more but less-sexy food, to give this woman ~1/2 of her food for one year, ~1/4 for the next two years, and declining amounts thereafter. Now, yes, this may be more pair-bonding than in chimps or bonobos. But it is also far less than the farmer ideal of life-long monogamy! Many men today reluctant to marry for life would be ok with this level of commitment.

Lynn Saxon has a new book Sex At Dusk, quite critical of Sex At Dawn. She was a kind enough sent me a copy, which I’ve just read. Searching, I’ve only find positive reviews of it (here, here, herehere).

Saxon doesn’t write as well, and especially fails to summarize well. Even so, she does successfully undercut many Sex At Dawn arguments. In humans, sexual jealousy is a universal, females are picky about sex partners, penises aren’t over-sized, testes are small, sperm production slow, and the evidence doesn’t suggest a great deal of sperm competition. Female chimps have little extra-group sex, bonobos don’t usually mate face-to-face, and many Sex At Dawn quotes are misleading, given their context.

On sound during sex, Saxon offers evidence that female primate cries during sex aren’t simple invitations:

A recent study of female chimpanzees found no support for the sperm competition hypothesis: females did not produce calls when mating with low-ranked males so it was not about inviting other males to join the party, and calls did not correlate with fertility and the likelihood of conception. … Females called significantly more while mating with high-ranked males, but suppressed their calls if high-ranked females were nearby. …

[Researchers] found that [bonobo] females were more likely to call with male rather than female partners but the patterns of call usage were very similar in that females called more with high ranked partners (as in chimpanzees), regardless of the partner’s sex. With a female partner compilation calls were consistently produces only by the lower ranking of the two females. … In bonobos the increase in calls during the alpha female’s presense. (p.279-280)

Yes, it looks like chimp and bonobo sex calls are more brags than invitations. Even so, brags make little sense when it is common knowledge who has sex with whom. So a habit of similar bragging sex calls by human females would suggest that humans often didn’t know who was having sex with whom, suggesting a lot of promiscuity.

A key question, to me, is what percentage of our forager ancestor kids were fathered outside pair-bonds. That is, what fraction of kids were born to mothers without a main male partner, or had a father different from that partner. This number says a lot about the adaptive pressures our ancestors experienced related to various promiscuous and polyamorous arrangements today. And hence says a lot about how “natural” are such things.

Alas, none of these authors give a number, but my impression was that Saxon would estimate less than 20%, while the Sex At Dawn authors would estimate over 50%. Even 20% would be consistent with a lot of human promiscuity adaptations, such as female sex brag calls. I asked Saxon directly via email, however, and she declined to give a number – she says her main focus was to argue against Sex At Dawns‘ “paternity indifference” theory (that humans don’t care which kids are theirs). Which is fine – that is indeed a pretty crazy theory.

So where does the evidence sit on promiscuity? Our closest living relatives, chimps and bonobos, are quite promiscuous. Yes, their pair bonds much weaker than ours, and pair-bonding usually greatly reduces promiscuity. But few pair-bonded animals live in big social groups where hidden extra-pair sex is so easy to arrange, and humans live in even bigger groups than chimps or bonobos. For humans, we have lots of clear evidence of outside-pair sex, mate-guarding to prevent such, bragging sex cries, and desires for sexual variety. And humans do seem to spend a record fraction of their time thinking about and doing sex.

Since humans usually have clear overt norms against extra-pair sex, but strong urges to arrange covert sex, promiscuity estimates comes down in part to estimates of how well humans actually enforced their norms. My homo hypocritus theory suggests a lot of covert norm violation, and so a lot of promiscuity. So I’ll estimate the key promiscuity number in the 20-30% range.

Btw, here’s another fascinating quote from the book:

Hrdy writes about a startling interview with an old hunter in which he reminisces to a time when just the sound of his footsteps on the leaves of the forest floor struck terror in the hearts of old women. He was the socially sanctioned specialist in eliminating old women deemed no longer useful: coming up behind an old woman he would strike her on the head with his axe. (p.216)

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  • manwhoisthursday

    Were there ever any evolutionary psychologists that denied a significant amount of female promiscuity?  It seems like just about everything in the book that was true was already acknowledged by evolutionary psychologists.

    • Robin Hanson

      Were there ever any who gave an explicit estimate for the key promiscuity parameter?

  • Anon

    “So I’ll estimate the key promiscuity number in the 20-30% range.”

    Khan’s discussion of paternity over there:

    I had heard the 20% range for cuckoldry (which should be related to the promiscuity number by the marriage rate) before, but it looks like that’s mostly for the lower class. Perhaps farmer and forager behavior are significantly different and show up in class data?

    • Robin Hanson

      I agree the % is far lower today; my estimate is re our forager ancestors.

  • Rob

    “…a noteworthy area that is poorly regulated socially, and which produces most of the serious conflict, is male competition over females.” (Also: )

  • R S

    The production of research about female promiscuity in humans and chimps further promotes forager sexual norms. High IQ men are catching on with evolutionary psychology and abandoning commitment (and the increasingly thankless investment it entails) at the same time that women are delaying marriage.

    The result is that men work less and women work more, and since the latter are less inventive (in terms of patents, Nobel Prizes or any metric you like) than the former, technological and economic stagnation ensues.

    • Anto

      You don’t take into account women oppression into the minor share of women prizes and inventions. That might be at least half cultural. In any case it is statistical and says nothing to the potential of each woman to be inventive and a genius. Also, less women achieved this but those who did it, did it no less than a men. So that’s the usual quantity vs quality, and quantity doesn’t say much about quality.

      • Samo Burja

        “You don’t take into account women oppression into the minor share of women prizes and inventions. ”

        It seems far more likely he simply does not find it convincing. Remember what you just pointed out is the default explanation we are taught in Western society, so nearly every educated person has heard the argument for it.

        ” That might be at least half cultural.”

        Ok on what data do you base this guesstimate?

        “In any case it is statistical and says nothing to the potential of each woman to be inventive and a genius”

        Of course knowing someone’s gender will give you information about the probability of observing future achievement or traits! On some matters this is weak Bayesian evidence on others it is strong evidence.

        In Fields Medals level mathematics it pretty much is strong evidence. Not that it obviously can’t be overturned by other strong evidence, like you know getting a Fields Medal.

        “Also, less women achieved this but those who did it, did it no less than a men. ”

        I don’t think we ever had a woman on the level of Von Neumann or Gauss. Marie Curie the best example of female genius in the natural sciences (of which there are suspiciously few in the 20th and 21st century if oppression is to blame) is not in their league.

        “So that’s the usual quantity vs quality, and quantity doesn’t say much about quality.”

        You are quite confused here. Quantity of quality is very important since human talent is so powerful and rare.

        Your post makes it very much look like you had your bottom line already written before thinking about the question.

      • Anto

        We are cultural people, yes there is the instinct too, but not too much to account for non heritable behavior, are you saying women are less intelligent?
        Knowing someone’s gender is not sufficient to infer the potential in anticipation. Every people obviously has to be singularly evaluated about this, otherwise we have prejudice and discrimination.
        We have women in astronomy, mathematics, every field, just less, but much more than in past.
        You are already judging me as irrational.
        Anyway in meritocracy this problem is not posed, we have to evaluate the single person.

      • Samo Burja

        “Knowing someone’s gender is not sufficient to infer the potential in

        This is an empirical question, the answer to which is different depending on what exactly you are interested in.

        “Every people obviously has to be singularly evaluated about this, otherwise we have prejudice and discrimination.”

        Wait I thought you where making an argument about anticipated experience not about morality?

        Obviously I don’t have time to get to know everyone. In my experience prejudice is what we call unflattering priors. I say it is bad only when you have bad priors (unfounded stereotypes) that mess up your map of reality.

        As to discrimination, well you obviously can’t have discriminating taste in company if you don’t discriminate! I will obviously discriminate on all sorts of things like how good a first impression they make, what their education is, do they smell, what kind of music they like… and now you will point out all of these things are things they can change, not something cruel nature or chance chained to their mind so it is ok to discriminate on that basis.

        But that’s changing the goal post from your original statement not? So discrimination is ok when it is about things people can control…

        In any case most people cant do much about not being beautiful, healthy or intelligent and everyone does discriminate based on that.

        So discrimination isn’t *always* bad. Just to prevent a flame war. Discriminating against a woman on say a job interview because she is a woman is a very stupid idea because the short conversation and her CV provide enough information to swamp out any possible information you gain her gender, except if you are hiring a male stripper.

        Also its illegal. 

        “We are cultural people, yes there is the instinct too, but not too much
        to account for non heritable behaviour, are you saying women are less

        Very small differences in preferences are incredibly important when looking at outliers. Same goes for any hypothetical differences in various kinds of ability, be that intelligence, drive or temperament .

        Men are more open to risk taking than women, men find working with people less interesting than women (which means everything else is relatively more interesting). Autism spectre disorders have been called the extreme male brain for a reason, even if that hypothesis is incorrect most people in that part of mind space are male ones. There is also evidence to suggest men have greater variance when it comes to intelligence, much like they have greater variance on most other traits. A wider bell curve means more outliers of all kinds.

        The small things add up.

        “You are already judging me as irrational.”

        I’m not judging, I’m just pointing out your argument provided no real substance.

      • Anto

        Let’s say you may have some points, I want a serene discussion about it. Ok women oppression, can’t be dismissed so easily, it’s what western society tells us, but that doesn’t mean it not necessarily true or just “politically correct”, it’s an established fact, that obviously doesn’t mean women are saint or never did wrong or that are geniuses. Take black people, someone could speculate there are less black scientists, but there are far more of them than when they were really oppressed, can’t the same be true for women? Marie Curie was (i assume) a high society and an assertive woman with a strong character, so I assumed she suffered less the bad terrain for women self enhancing. Think about a bad terrain for cultivation, less seeds grow fruits and less of them can be very tasty.
        “Wait I thought you where making an argument about anticipated experience not about morality?”
        It’s about the bearing pretending to anticipate experience has in morality, let’s say I’m more open than you about the notion that a woman can be equally potential to be a genius, depenting on how people are more close to this option there can be a consequence. That obviouslt doesn’t mean the proposition has to be false but it is delicate.
        “n my experience prejudice is what we call unflattering priors. I say it is bad only when you have bad priors (unfounded stereotypes) that mess up your map of reality.”
        Most prejudices against strangers so, one may say are not unfounded, because of a statistical bad experience, even if this “evidence” can easily messed up, and the same I could say about this “evidence” about women mind and potential, statistics might be old and factor might be very complex.
        But I can grant the prejudice is rational as long as you take this negative value assuming it as a possibility, but not projecting it to every individual of the same cathegory, let’s say someone could have had a bad experience with redheads, who are a minority, and also say there are less redhead scientists etc, you know what I’m talking about.
        About discrimination I can say I mostly agree, apart maybe about not moving from first impressions, but that’s ok and “obeys” somehow my “Anyway in meritocracy this problem is not posed, we have to evaluate the single person.”, so discriminating on the  base of result and skills on the single people, man or woman, with no prejudices about women being less skilled.
        I could raise anyway that the “terrain” could be still relatively unhospital for women developing the same share of outgoing people, sometimes it’s even their fault be it clear, you know, society encourages more comformism toward them, but much more of them are affirming and cultivating their intellectual skill, despite this situation, nowadas.
        As I said you could speculate as well about the lesser share of black inventors and such.

        “Very small differences in preferences are incredibly important when looking at outliers. Same goes for any hypothetical differences in various kinds of ability, be that intelligence, drive or temperament .”
        Wait, you are saying women are homologated and tend to homologation, just because they are woman, with no turning back, no cultural model bearing in this behavior, they just can’t help it, they are women. But couldn’t this be a biased perception of the opposite sex? I mean it also come from women the famous “men are all the same” :D. So no, I’m not convinced about this, or that their sex is to blame, being this eventually true, I can’t think about women as clones and comformists, not everyone. We both, I assume, could greatly see herd behaviour among every cathegory of people, and that’s an intricacy of cultural and instinctual trait. We cannot dismiss it as simply innate, at least not only.
        “Men are more open to risk taking than women, men find working with people less interesting than women (which means everything else is relatively more interesting).” Not sure about it nowadays, some young women are more indipentent than many men of their same age and more eager to take responsibility.
        “Autism spectre disorders have been called the extreme male brain for a reason, even if that hypothesis is incorrect most people in that part of mind space are male ones.”
        The last part is much more interesting, no irony and not saying the first three weren’t :).
        Yes I heard Asperger syndrome has much more incidence among males, and I wonder why…
        What struck me more is this extreme male brain notion, I can think about the apparent absence of emotion, the ability to keep track of many things and remember number and dates, extreme mathematical abilities.
        Another aspie I know has, instead just the abilty to remember things, but somehow has a sadistic – sexual side very developed, he also appears he fantasizes about women being in their power and completely disposable and objectified, I try do point out as how it is wrong, but there’s not talking with him about this :).
        “There is also evidence to suggest men have greater variance when it comes to intelligence, much like they have greater variance on most other traits. A wider bell curve means more outliers of all kinds.The small things add up.”It’s hypothized to have many social cause, sometimes I find even the instructions (of all kinds) given to women are more average and standardized, sometimes the first thing girls spend energy to derail to is their education and the comformism, from a life that seem prepared for them to settle down, I dunno, maybe it’s a field where we must simply admit we are not given knowing everything at all levels, about this cause and held mine and yours as hypothesis with some truth to it (i.e innate and cultural cause) that interlaces. It’s good to make a step back. For example i read that results on mathematics are catching up more with those of males and becoming more varying, among new generations.I just answered because I never heard before of blaming woman presumed “non inventiveness” for economic crisis (not your comment, I know):). Anyhow an interesting sex war theory this about more iq, less commitment (sex class clash, assuming women trying to tie man and man becoming more clever in making out without being trapped :D) , working less. Fascinating, even if I can’t share an ounce about it.”I’m not judging, I’m just pointing out your argument provided no real substance.” No, i simply didn’t developed my “counter” arguments enough.

    • Myrealitie

      Please validate your statement that “High IQ men are catching on with evolutionary psychology and abandoning commitment” 

      • gwern0

        At a first glance, if we credit Charles Murray’s statistics on upper-class America as being still big on marriage and *not* divorcing, and also the link between IQ and SES, that statement would seem to be false…

  • Wallace M Forman

    I’ve read that female copulatory vocalizations may help to induce orgasm in their partner. 

    Any support for this?

    • Richardsilliker

      Wallace. Nothing like the real thing.

  • Douglas Knight

    Which is fine – that is indeed a pretty crazy theory.

    How much should people devote to debunking crazy theories?

  • Mitchell Porter

    From the title, I was hoping that “sex at dusk” would be about sex at the end of human history, and how it differs from sex at the beginning. 

  • Melissa

    “penises aren’t over-sized”
    The real interesting thing is the diversity of penis size in humans. I don’t know if any study has been done on other primates, but it would not be surprising to me to find that humans are especially diverse. They have also found significant variation in genes related to pair bonding like oxytocin receptors. So in the end it might be very hard to write a book on human sexuality with a particular ax to grind. I enjoyed reading Sex at Dawn, but it seems at times they are trying to argue to a human sexuality based on their own somewhat unusual preferences. 

    • Doghouse Reilly

      Actually, I found this statement to be extremely surprising, given that human males have the largest penises of any primate. In light of this fact, I don’t understand why the author asserted that humans don’t have “oversized” penises.

      • Melissa

        Some surveys say that some populations have average penis sizes around 9-10 CM, which isn’t far off from the Bonobo (8 CM). However, those surveys often find countries where the average size is 16-18, which is quite enormous compared to any other primate. Most of the data quality from such surveys is low though, being often self-reported. 

      • primate

        The latest measurements from primate sexuality expert Alan Dixson are 10-18cm for chimpanzees and similar for bonobos. The length corresponds to the length of the vagina plus sexual swelling – these species produce copulatory plugs and dislodge copulatory plugs placed by previous males.
        The length of the human penis is in response to the position of the cervix which has changed due to our bipedalism. The thickness of the human penis is in response to changes in the females, also due to bipedalism and human childbirth and producing a  ‘fit’ between the sexes’.
        Humans, like other species, do not therefore have an ‘oversized penis’ as the penis and vagina and position of the cervix etc evolve in response to each other, each sex ‘trying’ to gain an advatage over the other over the control of fertilization.

  • Bill

    More noise when mating with higher status partners then with ~equal partners is bragging? It sounds more like flattery to me.

  • Gregory benford

    No eternal reward will
    forgive us now
    for wasting the dawn 

  • kurt9

    I read “Sex at Dawn” and found its arguments unconvincing. Male sexual jealousy is quite common and is at odds with the argument of the book.

    • Michael Rios

      It is dangerous to try to determine core human proclivities from observing behavior in a particular cultural context.  It is hard to overestimate how much culture can override nature.  I’ve heard many people in the US talk about how men are naturally less emotional than women.  This would come as a great surprise to my Southern Italian relatives, who consider it the woman’s role to be emotionally stable, in order to anchor the flamboyant emotions of the men– and there are many other cultures like that as well.

      I can speak from experience that male sexual jealousy is *very* much a cultural product.  I have the good fortune to be part of a very large extended polyamorous network, involving more than a thousand people, and sexual jealousy from either men or women is relatively rare, usually short-lived, and not a significant factor in much of anything.  And many of us did not have to work hard to achieve this lack of jealousy.  It was more like getting to a beach resort where no one expects you to wear a tie; what a delight to be rid of the useless thing!

      For instance, I was delighted recently that  one of my primary partners took on a lover who is a tantric master.  She comes back from spending time with him with new styles of lovemaking that we then try together.  (This is sometimes referred to as “technology transfer”.) 
      This connection had other benefits as well.  I had already known the man for quite a while, but somewhat distantly, and this has strengthened my connection with him significantly.  There is even a term among polyfolk for men who share the same lover;  “water brothers”– reflecting the bonding that can occur from that sharing.

      MFM triads are quite common in the polyamorous world, and are often *very* stable.  This would hardly be the case if male sexual jealousy were “hard-wired”.  

      More and more people are identifying as polyamorous, and more still as “open” (non-monogamous), and there is surprisingly little difficulty in this transition for many of them.  I can’t count the number of people, men and women, who have told me “I always thought I was defective, that I couldn’t commit to just one person.  Now that I know there is a name for what I am, and others like me, I can celebrate the fact that I can commit to *more* than one person!”

      Others find the transition more challenging, but this is not surprising, given the *vast* energy that the culture puts into defining monogamy as the *only* responsible sexual relationship.  But most of those folks manage to do quite well by talking with other polyfolk at gatherings and on e-lists, reading some of the many books on the topic, and attending conferences and workshops.  (Links to some of the best poly resources can be found at 

      The polyamory community, especially the persons who have been actively poly for decades, can be a fascinating resource for discovering what is and is not hardwired about our sexual relationship patterns– it is pretty astounding how many assumptions fall away once monogamy is not the only option.  

      • kurt9

         Interesting perspective, Mike. You’re probably correct.

        I will say this in my defense. I’m no social conservative. Trust me on this one as my comments through out the blogosphere should make this abundantly clear. I favor same-sex marriage and am generally pro-sex freedom. I am “liberal” on most social issues.

        However, I have enough experience to know that much of human emotion and character is “hard-wired” and that such must be considered when considering human relationships, both sexual and non-sexual, and that one must tread carefully when relating to others.

      • michaelrios

        If you study child development, you will find that virtually all human emotion is learned– and a stimulus that triggers a particular emotion in one person will likely trigger a very different emotion in another. Neuroscientists are finding that brain plasticity is much greater than they ever suspected. So it turns out that very little is hard-wired (though some things are). But how we respond emotionally is clearly not.
        If you went up to a dozen people, and said to each one “You are absolutely *repulsive*!”, they wouldn’t all react the same. One person might get angry, another might feel wounded, another would laugh in your face, another might simply wonder what was wrong with you, another might be afraid that you would escalate, and another person might just look blank– because they don’t speak English!
        I don’t think that “treading carefully” is all that necessary in relationships. There are certain skills and choices that are critical to having good relationships– but once they are learned, relationships of all types can flow easily and well. In fact, one of the workshops that I teach is called “Relationships without Drama”.
        What makes relationships work, in my experience, is transparency, clear boundaries, and compassion.

      • Lucas

        Mike, just curious but have you read Sex at Dusk?

        Sexual jealousy is *very* common in nature, more common than not really. It is a part of evolution (i.e. getting your genes forward). If a species doesn’t care whether offspring are theirs or not, that species would die out.

        Over-riding our genes is a very human trait. I would say that the *culture* of your polyamory community is what helps in resisting sexual jealousy (not the other way around).

        Sex at Dusk very clearly shows that the tribal cultures Christopher Ryan uses as examples of cultures with no sexual jealousy actually do have sexual jealousy, and very prevalently. Lynn Saxon uses the same research that Ryan used, but shows it in a much broader scope. Ryan just candy-coated and cherry-picked the research.

      • michaelrios

        I haven’t read Sex at Dusk. Both books are wild extrapolations, and neither should be taken as factual. What is interesting about Sex at Dawn is that it raises interesting possibilities and describes cultural and relational models that may be unfamiliar to many people. It could be a work of fiction, and still be valuable in this way.
        Humans are *extremely* malleable and adaptable. Claims of what is “natural” to the human species are usually ludicrous on their face. What matters is what works for the individual. But if people don’t know what their options are, they may not be able to find what works for them. For instance, when homosexuality was hidden, stigmatized, and persecuted, gay men had no good cultural models. So the gay culture was stigmatized as promiscuous and lacking in intimacy. Now that gay men can have socially sanctioned relationships, it turns out that many of them are homebodies, and are quite content to be pair-bonded.
        So the importance of Sex at Dawn is to make people aware that there are practical, ethical, and rewarding alternatives to possessive monogamy, and that these are not antithetical to human nature. All it really takes is to show that there is *one* stable, supportive culture in which includes these alternatives, and that the individuals who choose them can thrive.

      • Lucas

        “I haven’t read Sex at Dusk. Both books are wild extrapolations, and neither should be taken as factual.”

        If you have’t read Sex at Dusk I don’t think you can make that call. It is in fact a very objective book that doesn’t make any wild extrapolations – it presents scientific (peer-reviewed) evidence (It’s a science book on the level of any Dawkins book). Though you don’t seem to be blinded by Sex at Dawn, I still recommend you read Dusk. If anything it gives a good review of biology, and gives the truth about the cultures described in Sex at Dawn.

        “Sexual scarcity is entirely artificial…Group sex, “orgies”, and other multi-person sexual activities have been common for millennia…”

        Not disagreeing, but out of curiosity, what is your evidence for this? (Not Sex at Dawn I hope.) Sex at Dusk does a good job of explaining why sexual selectivity was important and necessary to the women of our tribal ancestors.

        In Sex at Dawn, Ryan tries to make the case that a child who has multiple fathers is treated as everyone’s child by the tribe – the true evidence however shows that a child like this it really treated by the men as no one’s responsibility, and rarely survives.

        “What is interesting about Sex at Dawn is that it raises interesting possibilities and describes cultural and relational models that may be unfamiliar to many people. It could be a work of fiction, and still be valuable in this way.”

        You have a point there (I mean, I find value in Star Trek), but I there is danger in presenting something like Sex at Dawn, which is supposed to be a science book, as truth. It can lead people down paths they may not otherwise take, thinking that this is the right way.

        I have some anecdotal evidence of my own, I know *many* people who had polyamourous relationships that completely and utterly failed in disaster. Hurt feelings, anger, fights, broken hearts… In truth I know more failed ones than successful.

        Don’t get me wrong though, I’m not trying to argue that such relationships cannot work, and I’m not trying to say that monogamy is necessarily the natural way – I’m just saying that sexual jealousy is a natural thing, evolutionary biology trumps evolutionary psychology in this.

      • Michael_Rios

        There are many things in your post above that I don’t think are supported by the evidence, but I don’t have time to go into every one of them. I will speak to this:

        “I have some anecdotal evidence of my own, I know *many* people who had polyamourous relationships that completely and utterly failed in disaster. Hurt feelings, anger, fights, broken hearts… In truth I know more failed ones than successful.”
        Of course, the same is true of monogamous relationships– the vast majority end unhappily.
        In a culture that provides no models for successful multi-partnering, it is no surprise that people who attempt that can often fail. However, I know far more happy, stable, healthy poly relationships than I do monogamous ones– and I specifically went looking for the monogamous ones!
        Unless you are in the poly community, you won’t hear about the successful ones. They don’t make much noise– they just live their lives quietly. In fact you may know *many* successful poly relationships–but because of the social stigma, they aren’t out, and you don’t *know* that they are polyamorous. 40 years ago, you knew lots of gays and lesbians– but you didn’t know that they were gay or lesbian, for the same reason. And many polyfolk have a different definition of success than monogamous people. Longevity by itself means nothing– I know plenty of monogamous people who have been married for 50 years, and they have spent those years limiting each other and tearing each other down.
        Many polyfolk consider a relationship a success if they create a bond with the other person, and if they learn and grow from it. My co-parent and I divorced 15 years ago, but we are closer today than ever. We no longer express our relationship sexually, but that doesn’t really matter to either of us. Both of us consider our marriage a success.

      • Lucas

        It’s been a while since I’ve put a lot of thought into this topic, but our main disagreement seems to be on whether jealousy is a part of our biology or if it is something fabricated by culture. I think there is ample evidence to support that jealousy is a part of nature, but I’m not going to convince you of that. And that’s fine – we can agree to disagree. No harm in that.

        Out of curiosity, have you read Sex at Dusk yet?

        One comment I’d like to make regarding your point that monogamous relationships often fail too. That doesn’t mean monogamy is unnatural. It just means that maybe long term monogamy is unnatural. Remember monogamy doesn’t have to mean a lifetime (60+ years) commitment. It may just indicate that serial monogamy is natural.

        You say that many poly people have a different definition of what a successful relationship is. Great, but you can also apply that to monogamy. For example you could define it as successful if you and your partner managed to have a child, raise a child, learn from each other, have a fun year together, etc. In that case a great majority of the statistically ‘failed’ monogamous relationships can now be considered successful. Monogamy can be defined simply as just wanting to be in a relationship with one other person.

        So how do you compare the two and say which is more ‘natural’? I think going with what the vast majority of people prefer, in all the countless different cultures across the world (even often in those cultures used by Sex at Dawn – as shown in Sex at Dusk) is ok to say that monogamy is probably more natural.

        Doesn’t mean you can’t choose to ignore nature, we humans are pretty good at that. (I dare say that driving a car is not natural.)

  • TGGP

    The last review given for “Dawn” from a journal of evolutionary psychology is by Ryan Ellsworth. That name doesn’t mean any more to me than most of you, but he cites a previous review (“Ellsworth, 2011″) almost as if its in the third-person. I suppose that’s common in academia, but to non-academics it produces a bit of a double-take. You can read his previous review in the same journal, The Human That Never Evolved.

  • TGGP

    Christopher Ryan, co-author of “Sex at Dawn”, was on recently: 

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  • open

    regarding men caring that the children they raise is their own, where does adoption fit in, many men are happy to raise adopted children. I understand the appeal of ones own offspring (I have two of my own). I think that many men would find that if  they knew that their biological offspring would be born badly disabled they would prefer to adopt.  The problem with all these discussions is the position that men or women are one way in regards to sex

    • Snakeinfur

       I personally think that both books are twisted by the authors own personal agenda. It is this assumption that males have a “long” refactor period in sperm production, “small” dicks and can’t love children that arn’t biologically theirs. I don’t think jealousy is ingrain. It is that insecurity brought on by socialization. Tribes where a child is believe to be shared among men offers a way of viewing a multiple parent household.

      I am more prone to believe Sex at Dawn then Dusk simply because Dusk follows the assumption that jealousy wasn’t a product of property ownership and agriculture.

      • Lucas

        Have you read Dusk?

        “I am more prone to believe Sex at Dawn then Dusk simply because Dusk follows the assumption that jealousy wasn’t a product of property ownership and agriculture.”

        How do you explain jealousy in hunter-gatherer tribes then? How do you explain jealousy in our primate ancestors?

      • michaelrios


      • Lucas

        That’s a bit of a semantics game. When a new alpha male lion kills the offspring of his predecessor, I’m sure he is not experiencing jealousy in the way that humans do, it’s more of an instinctual thing. But in the context we are discussing, you can still define it as such.

        You say there are “many human cultures and contexts that don’t experience or expect jealousy”, However the cultures that *do* experience it far outnumber the ones that don’t. (Also, if you are using Sex at Dawn as a source for any of these cultures, then I hate to say it’s a flawed resource.)

        You have a lot of anecdotal evidence for your view, and I have no doubt that it’s true and it’s great. I very much believe that our chosen values can direct our thinking and emotions – it’s something that makes humans unique. But that doesn’t change the fact sexual jealousy has a place in nature, and is a part of our evolution.

      • Michael_Rios

        The number of cultures that support jealousy is not a meaningful statistic. A couple hundred years ago, the number of cultures that supported slavery *far* outnumbered those that did not. The same could be said for those that allowed gays to be killed with impunity. All this shows is that human cultures, and human culture en masse, can change over time, and in some areas at least, become “better” in terms of human rights, ethics, and social justice.
        So I don’t think that sexual jealousy is necessarily much part of our evolution, since I have seen so many people drop it so easily. Many polyamorists find jealousy is easily dealt with (and some don’t, of course)– and as I pointed out, jealousy is not a fundamental emotion, but rather many different conglomerations of other emotions and triggers that get labeled “jealousy”.
        If sexual jealousy were so hard-wired, why would there be 10 million swingers in the US *despite* the incredible cultural pressures to be sexually exclusive? Why would orgies be so easy to find? (They are, trust me!) Why are threesomes, foursomes, and moresomes fun for many people? If sexual jealousy were so ingrained, it would be hard to find people who enjoy group sex. (It’s not, trust me!)

      • victorovich1990

        Hey Michael, 50 years? Care to share where these places are? I think I want to hunt down one or two of them :)

      • Michael_Rios

        Just to clarify: being in a cultural context that does not *expect* jealousy does not mean that no individual ever experiences an emotion that might be described as jealousy. Rather, the context does not validate or encourage jealousy, and the result is that “jealousy” is processed in terms of the individual’s own personal; growth, rather than externalizing their emotional challenge by trying to externalize it as caused by the actions of others.
        And some of the contexts I have been in have been acculturated this way for long enough that many of the individuals rarely if ever experience what most people would call jealousy. (I’ve already discussed how varied the meaning of that word can be.)
        One group that has such a context (for 20 years now) is the Network for a New Culture, although I know of many others. You can find out more at and You can write to me at

      • brookstyle

        “If I find my lover with another love, and they invite me to join them, jealousy would be a pretty odd response.” Really? I think jealousy certainly exists in animals. I think you see jealousy as a negative and choose to negate its existence for some pie in the sky idealism.

  • The Pragmatic Male

    Thanks for the recommendation! I enjoyed reading Sex at Dusk, even though I have not read Sex at Dawn. Sex at Dusk contained many useful explanations that I was unaware about. 

  • Muhry

    I’m not aware of any research on copulatory vocalizations in hunter gather populations. Sure, we know of loud sex in the developed world where people live in residences which allow us privacy not just from strangers but from family members as well, but do HGs make loud sex calls?

    As I understand it life in HG society was lacking privacy even when a person was in their hut. A mother would sleep beside her children and I doubt she would be bragging by making a sex cry while her 5 year old lay beside her. !Kung San woman claim to try and be discrete while having sex in order not to wake their children. Even then their children often wake and see whats happening. They don’t understand the mechanics but they see enough to start sex play quite young.

    It goes without saying that if a woman was in a relationship with a man she wasn’t going to be making sex calls while cheating on him within earshot of others.

    I’m not suggesting that HG women were silent, they expressed pleasure, but I’m not sure they gave the equivalent of women in the developed world who have the luxury of privacy.

  • Jessica Burde

    I haven’t read Sex at Dusk, and I had a mixed reaction to Sex at Dawn – some of their points were well made, and on others they were researched.

    It sounds like Sex at Dusk has some of the same problems. For instance sexual jealousy is not universal among humans, though it is common. Women being picky about mates is at least partly cultural (studies have been cited that women are just as willing to have casual sex as men WHEN THEY FEEL SAFE DOING SO [apologies for not being able to properly cite this]). Further, if women truly are picky about sexual partners it doesn’t mean we are inherently monogamous – I am damn picky about my sexual partners and I am polyamorous. Being willing to mate with multiple people does not mean being willing to mate with anyone.

    • Lucas

      Sex at Dusk’s strongest point (IMO) is that it shows how dishonest Christopher Ryan is with his ‘evidence’. Lynn Saxon uses the same research that Ryan used, but shows it in a more complete form. She shows how he completely misrepresented, candy-coated, and cherry-picked the data.

      It also gives a good evolutionary biology lesson as to why sexual jealousy exists in nature as part of evolution.

      As to your comment about sexual jealousy not being universal, I think the stronger case is that sexual jealousy is innate, but that some cultures repress it.

      • Toads

        Sex at Dusk makes assertions without even attempting at proving them with evidence. Instead it relies on a “well everyone knows that…” attitude, which is a logical fallacy. This assumption that everyone is innately jealous is just that, an assumption. It’s completely ignoring the evidence of the societies that don’t have the same kind of jealousy about sex. It’s also failing to prove that jealousy is biological as opposed to cultural. It’s problematic that you’re unable to have a critical mind when it comes to Sex and Dusk’s poor attempts at rebuttals.

  • Michael_Rios

    > her main focus
    was to argue against Sex At Dawns‘ “paternity > indifference” theory (that
    humans don’t care which kids are > theirs). Which is fine – that is
    indeed a pretty crazy theory.

    Not so crazy. This
    is another of those cultural dictates that seem immutable to those raised within
    it, and ludicrous to those who were not. The examples of treating children as
    the responsibility of the whole tribe or village are numerous and

    “You white people
    are so strange. We think it is very primitive for a child to have only two
    parents.” – Australian Aboriginal Elder”

    It takes a village to raise a child.” –
    African proverb

    In the language spoken by the Nepalese near Mt. Everest, the word for mother and the word
    for aunt are the same. Likewise, brother/sister and cousin, likewise father and
    uncle. This reflects a omplete lack of concern about biological parentage,
    even as to which woman bore which child!

    Worrying about which kid came from which
    parent is a cultural imposition, not a natural instinct, at least among
    humans.  My mother was of Puerto Rican extraction, and it was common for kids in
    one family who weren’t getting along with their parents, or if the parents were
    just overwhelmed for whatever reason, to be taken in by another family–
    sometimes a relative, sometimes not. Half of her very large family at any given
    time included children who were not the biological children of her parents, nor
    were they adoptees; they were just kids of friends or relatives that her parents
    took in. She even wrote a novel about it: “Never an Empty Room.”

    I grew up with much the same kind of atmosphere in my childhood home, and as an adult, have taken in numerous “wayward teens”– over 100 of them, over the years.  I also have 3 biological children–who have themselves “adopted” other parents, families and kids.  For a year or so, another family that we are close to actually swapped kids with us–we took theirs, they took ours.  It’s all one big family– it doesn’t really matter “who’s on first”.

    • Mr Spock

      >I also have three biological children<

      To know that you have three biological children does not sound like polyamourous reproduction to me.
      Sounds suspiciously like paternity certainty ;)

      • Michael_Rios

        ;-)  duly noted.  

        However, for those who aren’t familiar with polyamory, polyamorous relationships do not imply unconscious reproduction.  Being poly requires a much *higher* awareness of all aspects of a relationship, since nothing is taken for granted.  Monogamy is a kind of “kit” relationship; get married, and there are a hundred legal consequences, and even more than that many social consequences.  Polyamory requires careful thought and communication about what each relationship does and does not mean.
        So I’m quite certain of my biological paternity, for a variety of reasons.  But that doesn’t mean I claimed exclusive privilege of any kind in raising them, and when my kids needed other adults in their lives, they were free to arrange their living situation in whatever way worked best for them.  In fact, my youngest wrote an article while still a teenager called “An Abundance of Dads” that got published, describing his relationships with four men, all of whom he considered to be his dad.  I was proud to be included among them!   :-)

    • Lucas

      “Worrying about which kid came from which parent is a cultural imposition, not a natural instinct, at least among humans.”

      It is a part of nature and a natural instinct among many (most) animal species, so why not among humans? Genes drive our instincts, and the main drive for our genes is to propagate. It is much more likely that worrying about which kid is yours *is* a natural instinct, but that certain cultures (like the poly community) impose the view of not caring.

      No one is saying that we can’t love other kids or override our instincts, that’s what cultures do, and it’s a distinctly human trait.

      • michaelrios

        Hi, Lucas–
        I don’t intend this as argumentative, but exploratory. You are making a number of assumptions that aren’t necessarily true. I can think of many species where the males don’t have much to do with the young at all, or if they do, it isn’t directed at their own progeny specifically. So focusing on your own offspring, rather than treating all young of your species the same, is far from a given. Alligators, for instance, are just as happy to eat their own kids as some other gator’s kids.
        If you have some source to support your statement that males of most species focus on their genetic offspring, I’d like to hear about it.

      • Lucas

        The point is about breeding potential. The genes of animals drive them to produce offspring. I cannot think of any mammal species anyway that does not want to breed and have its own offspring. (Insects I can see, ants for example, workers are there specifically to help raise offspring that are not their own.) You can make the argument about wolves or lions, how lower class members help raise the alpha’s offspring – but the ultimate goal of the lower class is to become higher class an have their own. Success in nature is defined by having offspring. Even your alligator males fight for breeding potential – because they want to ensure their own offspring (not in a conscious way of course, but instinctual).

      • Toads

        Humans having sex with different partners in no ways undermines the drive to have have offspring. Bonobos, who we’re actually genetically similar to (unlike lions) , have sex all over the place. You realize that monogamy is extremely rare in the animal kingdom right? Researches have found that the animals that were thought to be monogamous actually tend to cheat on each other. If you use your model of looking at animals to inform us about human sexuality monogamy falls to pieces.

        If we actually examine all human societies you’ll find that not all of them follow the one mother one father formula. Apparently these societies didn’t get the same paternity obsessed biological memo the rest of us did? The fact that humans regularly adopt children that are not theirs also undermines this idea that we’re all naturally biologically obsessed with paternity.

      • michaelrios

        In an earlier reply (search comments for “Aboriginal”), I identified several cultures that pay little or no attention to which kid is biologically related to whom, including cultures in Australia, Africa, Nepal, and Puerto Rico, among many others. In one case, the language doesn’t even have *words* to identify or distinguish one’s biological children!
        In general, I suspect that the societies with the strongest capitalist and privatist values are also the ones that put a strong value on biological relationships. Cooperative, collectivist, and socially-based cultures tend to see *all* kids as everyone’s responsibility.
        And biologically, it doesn’t matter to a species whether a particular person’s genes are passed down; genes can be selected because they benefit the species as a whole. The book “The Selfish Gene” goes into some of this, and it is also necessary to explain menopause (virtually unique to humans) and other characteristics that don’t have direct reproductive benefits–of which there are many.

      • Chocolate Velvet

        Male lions, upon assuming control of a pride, will simply kill all the already extant cubs. It is an immediate priority. He kills them, the females go into estrous soon after, and his genetic material is propagated. This is a widely documented, and presumably instinctual behavior of male lions (among other animals). Paternity certainty is the whole point. If the purpose were simply breeding, all young would be protected by the incoming male. Gorillas will do the same thing. I highly doubt that is due to social pressures.

        These are just examples off the top of my head, there are many more. Do some reading or viewing and learn more about animal behavior, if you find the subject compelling in relation to human sexuality.

      • Toads

        Citing animals with males that care about their genetic offspring and others that don’t is a bit pointless. There are tons of examples in both camps. What a lion does has little to do with what humans do. Humans don’t sexually function remotely similar to lions. What nonsense.
        Female humans don’t show when they’re fertile, which is very different than other animals. Humans have sex without any chance of reproduction far more often than most mammals. It makes little sense to compare us to mammals who don’t really sexually operate in a similar way to us as if it proves something about humans.

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  • Lucas

    My two cents, (this is a review I posted elsewhere):

    I’ll start by saying that when I first read Sex at Dawn I was blown away. It completely changed my view of monogamy, sex, and relationships. It sparked this new openness and acceptance in me, and I will say had a very positive impact on my relationship. I thought here was the book that everyone NEEDS to read. I recommended it to everyone, talked about it with everyone, even called it my new bible (not that I put any stock in the old bible – being an Atheist, but you get my meaning).

    Then I came across Sex at DUSK. So, being a ‘seeker of truth’, I figured I owed it to myself to read this book as well. I really expected (i.e. wanted) Sex at Dusk to be a bad book in that it made a poor case, being full of religious and/or political bias, and couldn’t really negate Sex at Dawn. But what I found instead was a very objective, concise argument that pretty much laid waste to everything presented in Sex at Dawn.

    Lynn Saxon drew on the exact same research that Sex at Dawn used as evidence. However she showed a much more complete view of the research, she removed the apparent cherry-picking and candy-coating that Ryan and Jetha used, and showed that almost every bit of ‘evidence’ they used has been taken out of context, and presented in a way that is completely misleading.

    I am no expert in this field so I took the authors of Sex at Dawn for their word. I believed that the evidence they showed was honest and complete. Unfortunately it would seem that it isn’t. I am truly disappointed by their dishonesty.

    The other possibility is that the author of Sex at Dusk is being dishonest, but being that she is only showing more of the same research I would find it hard to make that argument, and I think anyone who reads it will also have a hard time making that argument. I highly recommend that any and all fans of Sex at Dawn read Sex at Dusk, and please if you come to a different conclusion than I did by all means comment here and explain.

    I honestly feel like I was cheated or scammed by Ryan and Jetha. I sincerely hope that they read this review and read Sex at Dusk to address the issues it brings up.

    • Alexey Sunly

      So, let me get this straight… You found yourself very happy and liberated by the ideas communicated to you in Sex at Dawn, but the minute another scientist decided to use the same facts and to back the dominant ideological paradigm that kept you miserable all this time, you are now back on the wagon?

      Here is an idea for you, Lucas, make up your own mind on what makes you happy and what doesn’t. Following a bunch of people in lab coats is not at all different from following people in uniforms or clergy. Science is not truth, it’s representation of truth. And it can be used to support any point you wish. Crazy, huh ;-)

      • Lucas

        Yes Alexey, and if wishes were horses, beggars could ride (or something like that).

        This has nothing to do with what makes me happy – I’m perfectly happy, but thanks for the concern :P

        I do make up my own mind – but I base it on evidence. That’s how reason works. And that’s how science works, as opposed to religion which doesn’t use evidence – that’s the difference.

        ‘Sex at Dawn’ doesn’t show facts, it misrepresents them. It’s dishonest.

        Thanks for your thoughts though.

      • Alexey Sunly

        Sex at Dawn do represent the facts, Lucas. Only in manner different from the way Sex at Dusk does it. They both represent facts as it suits their authors. Science can only examine theories and “evidence.” The conclusions are made by people like you. There is not right or wrong, only choices. Choices that make you happy and choices that make others either happy or unhappy. That’s all. And you are welcome for my thoughts :-)

      • Alexey Sunly

        The Myth of Monogamy: Fidelity and Infidelity in Animals and People, by David P. Barash and Judith Eve Lipton

        Why don’t you review this particular book as well for us, Lucas, and tell us how it “misrepresents” facts as opposed to the two already mentioned :-)

      • Lucas

        Here is a review of Sex at Dawn by David Barash you might find interesting:

        Haven’t read his book, would like to. From what I understand he is much more committed to truth/facts than Ryan is.

      • Alexey Sunly

        I am aware of Barash’s opinions, the question is what does Saxon has to say about Barash’ work… ;-) You thanked me for my thoughts, Lucas, but you are not listening. All facts can be “cherry picked” to support any truth, as long as you know what you are looking for, but you would know that if you were an academic yourself. If Barash is so committed to the “truth,” how is that the facts he “picks” contradict Saxon’s conclusions :-)

      • Lucas

        Saxon gave Brash’s book 5 out of 5 stars. And from what I understand both their books are pretty much in agreement in their conclusions.

        But you may be misunderstanding my position in this, I don’t really care what the conclusions are, what I care about is how dishonest Ryan is in his book. Both Saxon and Barash are in agreement about that as well.

        Of course facts can be be cherry-picked, that’s what I’m saying, that’s what Ryan is doing, but it’s dishonest and no it doesn’t show the truth, it shows an incomplete story – it misleads.

        You seem to be ok with the fact that Ryan cherry-picked the data to support his view. If that’s true, fine. We will just have to agree to disagree on that.

        In any case, I’m exhausted and probably not being as clear as I’d like. So I wish you a goodnight.

      • Alexey Sunly

        There is no complete story, Lucas :-) Science can not give you one, no one can give you one. Neither Ryan nor Saxon. Just read Barash’s book I mentioned, and I think you’ll see what I mean :-)

      • Lucas

        Who said anything about telling a complete story? I am well aware no one can be 100% accurate. The truth very well may be that our ancestors were polyamourous, or maybe they were monogamous, or maybe any different number of combinations of those. But that isn’t what I’m discussing. What I’m talking about is honesty. Honesty in the evidence you present. Ryan is not being honest in the evidence he presents. Cherry-picking is not honest (again, we will have to agree to disagree on that).

        Saxon’s book is about showing the full evidence – about how Ryan is being dishonest. Read it, you will see what I mean.

      • Alexey Sunly

        Alright, fair enough, you think Ryan intentionally tried to trick you then, huh? Well, I am sure he is so damn upset that he failed ;-) What do you think?

      • Lucas

        You can’t see it, but I’m rolling my eyes.

      • Alexey Sunly

        Exactly, because it does not matter whether you think Ryan is being dishonest. It makes no difference in this particular subject. Because no one is going to decide to have multiple partners and then use science to justify their choices. What they might do, like Ryan did, undermine the standard narrative that monogamy is the only way of being happy. And then have some silly evolutionary biologist like Saxon to prove the same, by “completing” the picture… which she never did :-) If you are still struggling with that, it’s fine. Maybe someday you will get it :-) Until then, enjoy looking for the Truth and nothing but the Truth!

      • Lucas

        Sorry Alexey, but I’m afraid you don’t get it. This isn’t about what anyone chooses to do with their lives or how they want to justify it, it’s about respect. I’ll quote Lynn Saxon from her blog (

        “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.”

        Respect for people does matter.

        In any case Alexey if you want to equate fiction with truth, more power to ya.

      • Alexey Sunly

        No, Lucas, you don’t get it, because most people don’t care about respect for evolutionary biology. Saxon, you, maybe some other poor souls who have nothing better to do. The rest of humanity just wants to live a good life and be happy, even if it means that you and Saxon call Ryan dishonest and disrespectful. What Ryan did was to focus people’s attention on the “facts” that human beings have a capacity and desire to lead a happier existence. What Saxon did was to tell us all the same boring facts that polygamy is not easy, and has never been so. Oh, yes, you really need a degree in evolutionary biology and 300 pages to tell everyone that? Sure, if you have nothing better to do.

        Now, as much as I enjoy trying to get through to you to help you to understand this, I am not getting paid for that! So, I’ll wrap it up here, and you can keep telling everyone how disappointed you are with Ryan’s thesis and methods, deal?

        Salut! :-)

      • Lucas

        All I’m going to say to that is that I think you are wrong, I think most of the fans of ‘Sex at Dawn’, do respect science to some degree. The very fact that Ryan is trying to pass it off as a legitimate science book is proof enough for that.

        And no, what Saxon did was not “tell us all the same boring facts that polygamy is not easy”. That’s not what her book is about at all. What she did was show us that Ryan was being dishonest about the science. Take the advice of David Barash, the author you seem to respect: read it for yourself. (Although, admittedly, since you do not care about the science, you may not find it all that informative.)

        “Sex at Dawn has been taken as scientifically valid by large numbers of naïve readers… whereas it is an intellectually myopic, ideologically driven, pseudo-scientific fraud.

        But if you must try Sex at Dawn—the book—you’d be well advised to chase it with Sex at Dusk, the antidote, which is not only a far better read but also more accurate and therefore considerably more exciting.” – David Barash

      • Alexey Sunly

        I read it, Lucas. I am not sure why you think I haven’t :-)

      • Lucas

        Because you come across fairly ignorant of it’s content, but my mistake.

      • Alexey Sunly

        And now you know :-)

      • Haha

        It is content. Great use of a contraction there.

      • Lucas

        Sorry Alexey, I have to disagree.

        Ryan show a ‘fact’ by only showing the part he wants, that seems (in its incomplete form) to support his claim. Saxon shows the fact in its complete form.

        Here’s a made-up example:

        Ryan says – “The research shows that villagers wore black, so wearing black is natural. You can wear other colors (like red or blue) but it’s not natural, it’s gonna be an uphill struggle.”

        Saxon would point out – “The original research shows that black hats were worn, and blue shirts and red pants were also worn.”

        FACT from original researcher – “The villagers wore black hats, blue shirts, and red pants.”

        See what I’m saying? That happens over and over in ‘Sex at Dawn’. Ryan is not simply showing the evidence in a different manner, he is cherry-picking. Again, it’s dishonest.

        Out of curiosity though, have you read ‘Dusk’?

      • Toads

        That sounds like finding minor molehills in the arguments and making them into mountains.

      • sirhotalot

        >Here is an idea for you, Lucas, make up your own mind on what makes you happy and what doesn’t.

        You shouldn’t think with your feelings. This is about facts of reality.

  • Reilly33

    From these comments, it seems that many people are relieved to have found a book, Sex at Dusk, that validates the cultural norms they are comfortable with. There’s almost no point in trying to have a rational, logical, or scientific debate which such people. Their response is always, “But this is how I am, so it must be true!”. Few people can admit their bias, and attempt to analyze information, without being subjective.

    • thehumburger

      I would say the same goes for both sides: most people of either opinion have their opinion first and are looking for something to validate it.

  • awr

    First of all, who sent the author of this article the book? Lynn Saxon is a pseudonym from what I understand. If you can’t publish a book with your own name eviscerating another book, it’s hard to hold much stock in it. Sex at Dawn still rings true to me regardless of what this book has to say. The fact that 50% of marriages end in divorce & so many people cheat would lead one to believe that we are not meant to be monogamous. Monogamy may work for some, but it certainly does not appear to be a standard that works for the vast majority of humanity.

    • sirhotalot

      In Western society maybe, but in hunter gatherer societies they are treated like property and thus everybody has sex with whomever they want as long as the man says it’s okay.

  • Books to read

    This is a poorly written article, I am not convinced that Sex at Dusk does a good job countering the claims of Sex at Dawn. The quotes in this article are poorly written, and the claims presented lack against Sex at Dawn scientific backing. 0/10

  • bonobo

    Agreeing with Books to read. “Another fascinating quote from the book:” Which book? You were writing about two different books! Gasp.

  • Toads

    Saxon’s “evidence” is hogwash. Small dicks? What the heck is the Sex at Dusk author talking about? The human penis is both longer and thicker than that of any other primate, both in absolute terms and relative to the rest of the body! It’s also an established concept that the shape of the human penis has been selected through sperm competition to serve as a sort of plunger. Jealousy over sexual partners is NOT universal, that is showing a cultural bias on her part. Females being picky about sex partners has nothing to do with if we’re monogamous or not. Being picky to the extent of only having sex with one person hasn’t really been proven if you examine the rates of cheating.

    • primate
      • Toads

        He’s saying that there would more likely be elongation of the penis in polyamorous species compared to monogamous species. This seems more like an argument for us not being monogamous since, once again, the human penis is both longer and thicker than that of any other primate, both in absolute terms and relative to the rest of the body. These studies are problematic as well because many once thought “monogamous” animals have upon further research have been found to commonly cheat.

      • reader

        A chimpanzee, not more than five feet tall, has a penis averaging five and one half inches, range four to seven inches. I would say that this is relatively longer than the human penis. As for thickness, what does this really tell us? Why is the penis of the promiscuous chimpanzee and bonobo so thin (and, I presume, the penis of other primates with a multi-male mating system)?
        This suggests we need to look at other factors, including what is going on in the female. In humans this means looking at how bipedalism and big babies changed female genital anatomy.
        As for monogamy not being strict sexual monogamy, the “standard narrative” that “Sex at Dawn” criticizes also is about this “cheating” in humans and about sperm competition. No one is arguing that we are strictly sexually monogamous.
        But it is complicated.
        Testes size, for example, is usually a better indication of sperm competition (and ours suggest some). On this point it is interesting to note that gibbons have relatively larger testes than do humans as pointed out in the comments of this blog (from 2009 and involving Ryan):

  • James

    Another reply to Ryan (and Ryan responds in the comments)

    • James

      oh and this is evidently from someone at UCLA Anthropology.