(This post is the beginning of a short sequence discussing evidence and arguments presented by Christopher Ryan and Cacilda Jethá's Sex at Dawn, inspired by the spirit of Kaj_Sotala's recent discussion of What Intelligence Tests Miss. It covers Part I: On the Origin of the Specious.)

Sex at Dawn: The Prehistoric Origins of Modern Sexuality was first brought to my attention by a rhapsodic mention in Dan Savage's advice column, and while it seemed quite relevant to my interests I am generally very skeptical of claims based on evolutionary psychology. I did eventually decide to pick up the book, primarily so that I could raid its bibliography for material for an upcoming post on jealousy management, and secondarily to test my vulnerability to confirmation bias. I succeeded in the first and failed in the second: Sex at Dawn is by leaps and bounds the best evolutionary psychology book I've read, largely because it provides copious evidence for its claims.1 I mention the strength of my opinion as a disclaimer of sorts, so that careful readers may take the appropriate precautions.

The book's first section focuses on the current generally accepted explanation for human sexual evolution, which the authors call "the standard narrative." It's an explanation that should be quite familiar to regular LessWrong readers: men are attracted to fertile-appearing women and try to prevent them from having sex with other men so as to confirm the paternity of their offspring; women are attracted to men who seem like they will be good providers for their children and try to prevent them from forming intimate bonds with other women so as to maintain access to their resources.

This narrative is remarkable for several reasons. In Chapter 2, Ryan and Jethá point out that it fits in neatly with much of Darwin's work, which famously drew upon Malthus and, to a lesser extent, Hobbes. The problem here is, of course, that Malthus's theory of population growth was wrong (see Michael Vassar's criticism and my reply). Like Hobbes, he looked at his society's current condition and assumed that prehistorical man lived in a similar state; the book calls this unfortunate tendency "Flintstonization" after the famously modern stone-age cartoon family. Those familiar with the heuristics and biases program may recognize this as an example of the availability heuristic.

The human population of the earth exceeded 1 billion individuals when Darwin was writing his works on human evolution, and his conclusions were drawn from the study of living individuals in densely-populated modern cultures; it is remarkable that these findings are claimed to be equally true of the small bands of immediate-return foragers2 that defined anatomically modern human existence between the time they emerged roughly 200,000 years ago and the adoption of agriculture 190,000 years later, during which period there were likely no more than 5 million human beings alive at any one time (to offer a very generous estimate).

Unfortunately, many prominent evolutionary psychologists seem to think it's obvious that these situations should be parallel, as can be seen in the ubiquity of justifications of the standard narrative based on just-so stories and studies performed on undergrad psychology majors. (Examples to follow momentarily.)

Another curiosity is that, "where there is debate about the nature of innate human sexuality [among supporters of the standard narrative], the only two acceptable options appear to be that humans evolved to be either monogamous or polygynous." (Ryan and Jethá, 11, emphasis theirs.) This has been amply demonstrated by a number of commenters on my recent post about the common modern assumption of monogamy. The idea that humans of both genders might be naturally inclined to have multiple partners didn't get much mention3, despite an embarrassing wealth of evidence supporting that position. But I'm getting ahead of myself; the anthropological and anatomical support for the multiple-mating hypothesis will be covered in my next two posts.

In Chapter 3, Ryan and Jethá focus on four major research areas that are used to support the standard narrative. These lines of research all rely on Flintstoned reasoning; taken together, they lead to the standard narrative's conclusion, which Ryan and Jethá summarize as "Darwin says your mother's a whore." (50) The four areas are:

The relatively weak female libido - Donald Symons and A. J. Bateman have both claimed (among numerous others) that men are much more interested in sex than women are. (Pay no attention to the multiple orgasms behind the curtain.) One of the most cited studies in evolutionary psychology purports to demonstrate this by comparing the responses of men and women when solicited by strangers for casual sex. But such studies do not distinguish between social norms and genetic predispositions, leaving evolution's role commensurately cloudy.

Male parental investment (MPI) - Robert Wright wrote in The Moral Animal that "In every human culture in the anthropological record, marriage... is the norm, and the family is the atom of social organization. Fathers everywhere feel love for their children.... This love leads fathers to help feed and defend their children, and teach them useful things." He is not alone in this view, but the argument is based on a number of dubious assumptions, especially that "a hunter could refuse to share his catch with other hungry people living in the close-knit band of foragers (including nieces, nephews, and children of lifelong friends) without being shamed, shunned, and banished from the community." (Ryan and Jethá, 54)

Sexual jealousy and paternity certainty - David Buss's research has demonstrated that, on average, (young, educated, modern, Western) men are more upset by sexual infidelity than women, while (young, educated, modern, Western) women are more upset by emotional infidelity than men. Or, at least, this is true when subjects are given only those two options; David A. Lishner repeated the study but also offered respondents the option of being equally upset by emotional and sexual infidelity. In his version, a majority of both men and women preferred the "equally upset" option, which substantially narrowed the gap between the sexes. The remainder of this gap can be further narrowed by the finding that women asked this question are more likely than men to assume that emotional infidelity automatically includes sexual infidelity. (This paragraph has been edited to fix a reasoning failure that was pointed out to me by a friend.)

Extended receptivity and concealed (or cryptic) ovulation - "Among primates, the female capacity and willingness to have sex any time, any place is characteristic only of bonobos and humans." (Ryan and Jethá, 58) While Helen Fisher has proposed that in humans this trait evolved as a means of reinforcing a pair-bond, "this explanation works only if we believe that males--including our 'primitive' ancestors--were interested in sex all the time with just one female." (Ryan and Jethá, 60, emphasis theirs.)

Chapter 4 expands on the role that the other apes play in the standard narrative. Arguments that evolutionary psychology should focus on the gibbon as a model of human sexuality are frequently attempted on the grounds that they are the only monogamous ape. But gibbons are the ape most distantly related to humans (we last shared a common ancestor ~20 million years ago), live in the trees of Southeast Asia, have little social interaction outside of their small family units, have sex infrequently and only for purposes of reproduction, and aren't very bright.

The chimpanzee model provides much more coherent support for the standard narrative: like modern humans, they use tools, have intricate, male-dominated social hierarchies, and are highly territorial and aggressive. The most recent common ancestor they share with humans lived approximately 6 million years ago, by most estimates. (I originally wrote "between 3 million and 800,000 years ago", which is untrue. Thanks to tpc for pointing that out.) There is just one unfortunate snag: "among chimpanzees, ovulating females mate, on average, from six to eight times per day, and they are often eager to respond to the mating invitations of any and all males in the group." (Ryan and Jethá, 69)

Helen Fisher, Frans de Waal, and other advocates of the standard narrative have claimed that the success of the human species is directly due to the abandonment of chimpanzee-style promiscuity, but they lack a convincing explanation for why this abandonment should have occurred in the first place. Worse yet, there is a particularly important piece of evidence that they are reluctant to acknowledge:

Given the prominent role of chimpanzee behavior in supporting the standard narrative, how can we not include the equally relevant bonobo data in our conjectures concerning human prehistory? Remember, we are genetically equidistant from chimps and bonobos. (Ryan and Jethá, 73, emphasis theirs.)

Oddly enough, bonobos have patterns of sexual behavior that are more like those of humans than any other animal. They hold hands, french kiss, have (heterosexual) sex while facing each other, and have oral sex. Compared to chimps, they're more promiscuous, more egalitarian, less violent, and less territorial. If it seems like this should be evidence for a multiple-mating hypothesis for humans, well, it is. The next post in this series will examine the anthropological evidence Ryan and Jethá use to support this view.

1: I have necessarily omitted much of the evidence that Ryan and Jethá provide in favor of their claims. Please feel welcome to request further information if there are any points you find particularly dubious; while I am not an expert in this field, I will at least attempt to pass on the sources cited.

2: Immediate-return foragers are those who eat food shortly after acquiring it and do not make significant use of techniques for its processing or storage.

3: I was admittedly among those dubious of such a conclusion.


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My Evolutionary Psychology class never claimed that people are naturally monogamous or polygynous. The "story" is much more complex than that.

For example, we learned that women are more likely to cheat on boyfriends/husbands while ovulating. They also are more likely to find feminine male faces attractive while non-fertile as compared to when they're fertile. When ovulating, they find highly masculine faces more attractive. This fits well with evo. psych explanations for human sexuality (securing a feminine male's resources and parental care and a healthy, masculine male's genes) but it is neither monogamous nor polygynous. Nor is it polyandrous. Those are idealized concepts that don't get at the selfish-gene replicating nature of human sexuality.

Agreed regarding the standard content of science-grade evolutionary psychology. That's what people who actually make and test predictions say.

It seems to be the case though that most supposed evolutionary psychology is speculation based on fairly long logical chains with fairly high probabilities associated with each step and a lack of awareness of conjunction fallacies. This method can work, but it isn't science, and when combined with motivated reasoning it's not one of the methods of rationality either.

6Eliezer Yudkowsky13y
If it produces successful advance predictions - if you do new experiments to test the idea and they seem to come out pretty much the right way - then it's probably working well enough.
Agreed. But that's mostly not what goes by the name. Also, massive modularity isn't necessarily due to genetic biases. T&C Evo Psych consists of a number of logically distinct hypotheses, some of which are true but obvious, some true and non-obvious, some false. Most Evo Psych is basically what I just described.

This post doesn't make a convincing argument for any of its points. You go all over the place, hinting that many people may be wrong, but you don't nail it down that they actually are wrong. Your main objective seems to be proving that the ancestors of humans were polyamorous rather than monogamous or polygynous. If you believe this thesis, you probably have good evidence to support it. Why not just list this evidence instead?

Haven't read the book yet, but here's the supporting evidence I gathered from the Amazon.com preview and the authors' website and blog. (I probably missed some so please add to the list.)

  • females have potential for multiple orgasms
  • higher popularity of pornography with one female and multiple males compared to one male and multiple females
  • female copulatory vocalizations
  • male anatomy indicating sperm competition
  • Coolidge effect in females
  • it fits better with "fierce egalitarianism" of forager bands: female sexual exclusivity is necessary for males to determine paternity, but if all resources are equally shared, then there is little point in knowing paternity
  • ETA: our closest primate relations, chimps and bonobos, have "multimale-multifemale mating systems"

On a separate note, while it seems plausible that the authors of the book are right that our forager ancestors were polyamorous, it's not clear why that matters to us in making our own choices, given that our ancestors switched over to monogamy/polygyny as soon as agriculture was invented.

female sexual exclusivity is necessary for males to determine paternity, but if all resources are equally shared, then there is little point in knowing paternity

This sounds weird. Your genes don't want you to know you're the father, they want you to be the father, and female sexual exclusivity helps with that.

Actually, your genes want both, since if you know you are the father then your genes can help direct you to giving more resources to your offspring rather than others. Indeed, there are plausible payoff matrices one can construct where one would rather have fewer offspring but be more certain which offspring are yours.
Correction accepted, but it doesn't apply in the "fierce egalitarianism" scenario that Wei Dai mentioned.
Yeah, I agree. If one assumes near complete equidistribution of resources then it won't apply.
You actually don't need to "know" which offspring are yours. You just need to direct more resources towards them. In fact not knowing a child is yours in a fiercely egalitarian culture might help you find good excuses for why you treat him preferably to other children. One just needs to "like" that child more for some reason and then the rationalizing mind will find ways to justify or conceal this preferential treatment. A more finely tuned subconscious kin recognition system based on visual appraisal of facial features (if I recall right men do prefer children that are more similar to themselves) or perhaps something like smell might do the trick.
Yes, each male's genes would want him to gather a large harem and enforce sexual exclusivity for "his" females, even if he couldn't preferentially contribute resources to his own children. But how is he supposed to accomplish this in an egalitarian forager band? On the other hand, a female's genes would want her to be sexually exclusive, voluntarily, if that meant her children's father would preferentially contribute resources to them. Otherwise, they prefer sperm competition, since that gives her a better chance of getting the fittest sperm, and increases the genetic diversity of her children. (At least that's my understanding of the authors' logic.)
Your genes might also want you to signal that you don't know who the father is so that your altruistic actions towards the child are seen as altruistic rather than selfish. It's a just-so story, but not crazy. Alternatively, sexual feelings might be radically genetically undetermined, less genetically determined than almost everything else about us, to partially prevent red queen's races, runaway sexual selection, inbreeding caused by agreement with parents regarding sexual preferences, and excess conflict over fitness-irrelevant superficialities. This combination of intensity and flexibility in a drive might make our sexual feelings radically flexible, and thus make them such a good lever for manipulating group dynamics that meme-level group selection reliably grabs onto them and adapts group sexual norms that shape our broader psychology to the group's adaptive niche.
Yes, but sperm competition is an easier departure from small, reciprocally altruistic forager bands. Pre-agriculture, defecting in that particular Prisoner's Dilemma led to either death or a much narrower selection of mates. Getting rid of the strict enforcement of resource sharing (by adopting agriculture) is the discontinuity that makes this counter-intuitive.
Ah I've see you've thought of the effect of agriculture, I should have read all the comments before posting.
Your point was a good one. The societal changes wrought by agriculture cannot be emphasized heavily enough.
9Eliezer Yudkowsky13y
Supply-driven. Male actors are much cheaper.

Men viewing erotic material suggestive of sperm competition (two men with one woman) produce ejaculates containing a higher percentage of motile sperm than men viewing explicit images of only three women.

(Ryan and Jethá, 231, referring to research by Kilgallon and Simmons)

I'm finding it a bit hard to draw that conclusion from this when there's no precisely-one-male-present condition, and I don't see any mention of any experiments that did do that in the actual article, either. It could just be due to the presence of a male, and not the number of them. Perhaps more importantly, it's also not clear that what pornography men like should correlate with what causes them to produce more motile sperm!
I would be surprised if a greater number of male actors does not also result in a salary increase for the actress. This does not contradict your point, but it may undermine it; I'm hardly familiar with pay structures. More significantly, what would you need to observe to conclude it was demand-driven?
I agree with you on this. However I think you need to realize something else. Hunter gatherers are relatively egalitarian, farmer communities and especially city dwellers are not. A fair number of humans have been exposed to selective pressures since the dawn of agriculture and civilization. There is no doubt that we see changes of typical skeletal features in the last 40k years (especially the anomalous shrinking of brain size accompanied by growth in the "advanced" regions, which defies the previous trend of the past few 100k and perhaps even million years as shown by the fossil record to be the case among all hominids (not just Homo Sapiens)), modern geneticists also see many sweeps still taking place in modern populations. Harpending and Cochran postulate on this and other things that we've seen major genetic change, especially on genes that affect things like like behaviour, infectious disease resistance and digestion in historical times. Perhaps we are ill suited to monogamy and patriarchal sexual polygamy (one husband many wives) because we just recently started responding to pressures in its favour (that have also recently nearly desisted with the advent of equality of the sexes and contraception). Evidence that at least some preference for monogamy may exist is the dropping rates of polyandrous marriage in the Himalayan region as soon as the economic circumstances allowed different arrangements, while people are today only slowly responding to the de facto legal, reproductive and financial disincentives for monogamous marriage. However a counter point may be tropical Southern Chinese (a few smaller ethnic groups still practice this) and West African farmer communities where we don't see such a patriarchal pattern. But perhaps this is due to the different economic trade offs of their particular type of agriculture. Also at the end of the day maybe I'm mistaking pastoral patterns for agricultural patterns of selection since Eurasian and East Africans peop
Thanks. Sounds like an interesting and plausible scholarly argument!
I don't think that the point is that a particular view is right, so much as that a particular view is wrong. I don't think that there's quite adequate evidence to conclusively disprove such a hypothesis, only evidence to call it into question, which this does, if imperfectly. I think the author is erring on the side of readability and not enumeration of evidence.

The Sex at Dawn story is nice but the whole debate seems backwards.

Everyone picks their favorite modern social models and then molds citations and stories to support that it must be natural and even the ancient hunter gatherers...

Popularized evo-psych seems to be a lot like appealing that a certain way of life is "natural" and thus "good".

btw Is there a name to the "natural -> good" bias/fallacy?

It's called the naturalistic fallacy.

You're right that the debate seems backwards. Evo psych should be used to make correct predictions and find optimal actions, not create or justify moral norms.

N.B. This is the less common use of the phrase "naturalistic fallacy", and where possible "appeal to nature" might be preferred (when describing an argument).
No, "appeal to nature" is the much more common use of "naturalistic fallacy," unless you only count use by philosophers.
9Eliezer Yudkowsky13y
Does anyone actually do this? Do I just hang out in the wrong circles? Are there people who do this and yet I never talk to any of them or read anything they write?

I have definitely seen it leveled as an argument against feminists (or, more generally, pro-altruist exhortations.) Men are evolved to cheat on women and be bad fathers, so don't ask them to do otherwise. Humans are evolved to make war, so don't ask them to do otherwise. You hear a lot of evo-psych from people who have a generally pessimistic view of human nature: everybody's mean, nobody is nice, all niceness is futile.

I find that attitude exhausting and the associated arguments usually overstated. But hey, that's just me.

The standard rejoinder is that women are evolved to ask men to stop cheating, so men shouldn't ask them to do otherwise.

I've evolved to stop talking to people who abuse evolutionary psychology.

Such pessimism is dangerously close to fatalism, and wrong for the same reasons. Just as we have reasons to contemplate our choices despite their inevitability, we have reason to fight our bad urges even under the (weaker!) influence of genetics. And then there's the fact that societies with stronger norms against infidelity had less of it, suggesting that men "had the willpower all along!"
Yes people do it. Most of the time actually. You just hang in the right circles to avoid it.
Yes, unfortunately people do this.
Ever been in a health food store? And then of course there's this [http://en.wikipedia.org/wiki/Crime_against_nature].
Sex at Dawn doesn't talk about any modern social models. One of its central points is that the lives of hunter-gatherers were radically different from the lives of everyone born after the adoption of agriculture. The authors aren't making any moral claims, so far as I'm aware. They're just trying to figure out how evolution shaped our sexual psychology; while this should probably tell us quite a bit about how to conduct our sexual affairs in the modern world, that's a topic they touch on only very briefly, and they draw no particular conclusions.
That's only true if one accepts the basic evolutionary psychology premise that we have a strong bias towards a particular pattern such that any other pattern will cause unhappiness and psychopathology. What if psychopathology comes from conflict between individual idiosyncratic sexual feelings (caused by early, incorrectly locked-in interpretations of group norms?) and group norms?
I don't accept that premise and I still think it's a point worth investigating. It's obvious that monogamy does make many people happy, but justifying it by an appeal to nature that isn't even true does few favors to the >50% of people who have been failed by the ideal of life-long monogamy. It's as good an explanation as any other, I suppose. Ryan and Jetha do talk a bit about paraphilia in men, but that chapter disappointingly lacked the rigor displayed elsewhere, so I wasn't planning to discuss it.

I think, WrongBot, that you may have bit off more than you can chew. I'm sure rationality can be deployed talking about sexual mores, but it is probably even harder to do than in politics.

In politics, people have to at least pretend to be vaguely rational or their opponents clobber them with good counter arguments, whereas with sexual stuff most people frequently lie, and are sometimes are even consciously rewarded for doing so.

If you insist on pushing forward, I'd recommend not posting anything until you have a reasonable idea of the order in which arguments and claims will be posted so that you never have to say that evidence for a conclusion in "this" post "will be covered in my next two posts". Seriously... diagram the claims, the lemmas, and the evidence in a tree (or a web?). Then start at the bottom (with the evidence) converting article sized chunks of the diagram into essays with clean prose, helpful pictures, and a review for logic and typos before you post it.

Basically, start with the evidence and proceed to the bottom line.

It doesn't matter whether Malthus had shaky assumptions in a paper two centuries ago. (And it seems weird to me that you woul... (read more)

None of the groups cited in that article are nomadic foragers. This sequence is not heading towards "We should all be polyamorous and be happy forever." First, the multiple mating practiced by prehistoric foragers more closely resembles the behavior of bonobos than it does modern polyamory. Second, this isn't my material. I am presenting content from Sex at Dawn, and foolishly thought this sequence should follow roughly the same order of presentation as the book; I will not make such a mistake again.
The other half of my response - broken in two so the discussion can branch naturally :-) Perhaps I misunderstood this bit: I interpreted this to mean that you knew that your beliefs were nonstandard and your beliefs became more extreme after you were exposed to evidence. So I guessed that before reading you thought (guessing and summarizing here for concision, apologies if I miss the details) (1) that standard narratives about sexual relationships are confused enough to indicate that people could profitably reconsider their own sexual habits (as per your recent Unknown knowns: Why did you choose to be monogamous? [http://lesswrong.com/lw/2ee/unknown_knowns_why_did_you_choose_to_be_monogamous/] post which I understood to be the first post in the sequence), and after reading the book, you thought (2) that this was still more true. If these assumptions were correct, the implication would be (1) this is a case where most people really are wrong/crazy and exposure to evidence makes people justifiably extreme, or else (2) you were admitting to becoming more extreme in your beliefs because something lead you to discount evidence that disconfirmed your preferred theory while remembering and repeating confirming evidence. I thought the admission was very admirable, because that kind of self awareness is rare and seems usually to require effortful mindfulness. Even if you haven't processed through to an update based on that kind of meta-recognition, noticing it would be pretty impressive. The admission implied that you were aware that you were grinding an axe of some sort... If you think I misinterpret the nature of your planned advocacy, please let me know :-)
My post on unknown knowns isn't really related to this sequence (and that's why I identified this post as the sequence's beginning), but that's just a nitpick. I'm trying hard to avoid making any prescriptive conclusions in my discussion of Sex at Dawn, and instead to stick to unraveling the evidence about the conditions under which human beings evolved. Before I read the book, I thought that "polyamory as popularly defined is basically a kick in the teeth to evolution [http://lesswrong.com/lw/2ee/unknown_knowns_why_did_you_choose_to_be_monogamous/27cd?c=1]." Sex at Dawn makes a convincing case that the opposite is true, which may mean that polyamory is a better idea in the modern setting than I had thought. But I'm still very uncertain on that count, because the modern setting and the evolutionary setting are so different that what is adaptive in one is often totally crazy in the other. When I picked up the book, I was expecting that the case it made would be bad and that I might be tempted to agree with it anyway because I am generally a fan of polyamory. I can't say definitively one way or the other whether I succumbed to that temptation: the book's case seems like a very good one to me, which could either be true or the product of a motivated evaluation. I think that it's the former, but that is itself evidence that supports both hypotheses. The axe I'm grinding is, I suppose, that I don't think monogamy is built into the universal nature of human beings. This hardly seems like an axe to me, but a number of vehement objections seem to indicate otherwise.
OK, so now I'm thinking back to the first thing I said, which is that this subject is more difficult to talk about in public (without things going off the rails) than politics - so I think you should expect craziness on this subject. I mean, laws about sex and relationships are frequently used for political purposes to increase the emotional drama of politics in order to get people worked up enough to vote... I think my priors for this conversation were messed up but are improving, maybe? Each time I see more of your writing on this subject I'm surprised again, but a bit less so. In the "poly kicks evolution in the teeth [http://lesswrong.com/lw/2ee/unknown_knowns_why_did_you_choose_to_be_monogamous/27cd?c=1]" link I was left scratching my head wondering why "Polyandry is no more egalitarian than polygyny; any relationship in which only one person is permitted to have other partners lies outside polyamory's accepted definition". I would have said that in a threesome, logically speaking, there are three dyadic partnerships and each person has two partners, but I think maybe you assumed (1) that no one is non-heterosexual, (2) only sexual partnerships count, and (3) all groups have at least one penis and at least one vagina (so you can't just have three wives or three husbands in a closed but poly relationship). I mean, if we're ignoring all of our assumptions about human nature, why not treat orientation as "bisexual until tested" (reference [http://swearindf.blogspot.com/2010/06/macho-calado.html] for those who missed the joke) and therefore assume that unless otherwise specified the problem with a closed relationship with "2 of one gender and 1 of the other" is that the 1 doesn't get enough variety in their life because they only get to have sex with the opposite gender... instead of always having that "little extra bit of variety in their married life" :-P For a more "normal" scenario, the traditional explanation for polyandry in Tibet [http://en.wikipedia.or
A triad in which all three people are involved with each other, regardless of gender, absolutely counts as polyamory. As typically practiced, I believe, polygyny and polyandry don't, because the man or the woman, respectively, is the only one allowed to have multiple partners. (For the record, I'm bisexual, so I was definitely not assuming (1).) I've been poly for ~4 years, which substantially predates my discovery of any sort of rationalist community, though I would have happily identified myself as a rationalist from about age six onward. Polyamory is unquestionably the right approach for me; while I doubt that that is universally true for all people, I believe it is worth careful consideration, and that many would find it advantageous to adopt. So, yes, I'd agree with (1) here. As for (2), well, this post is the first in a sequence that is describing/summarizing arguments from a book, but the authors are not (to my knowledge) polyamorous, nor does the book make a strong conclusion in favor of polyamory. If I have been biased or defensive on this topic elsewhere, that is my failing alone.
I thought about this for a while, and I think I just wanted to say that I appreciate your reasoned, revealing, and responsible tone. Also... This would make a fantastic opener for a post. It offers a basis for your expertise on the subject and then a wonderfully clean thesis whose well-argued justification would probably be very educational. By setting the bar at "unquestionably for you" and "high value of information [http://en.wikipedia.org/wiki/Value_of_information] for nearly everyone" the justification would probably involve evidence and reasoning that was quite striking :-)
Why, thank you. I'm hoping that, between my Unknown Known post and this sequence, I'll be able to do a pretty decent job of demonstrating the high value of information claim. As for why it's so awesome for me, that really has more to do with quirks of my own psychology than anything else. Just off the top of my head: * It makes me miserable to have to think about relationships in terms of opportunity costs. * I prefer to do most of my socializing with well-known and well-trusted friends. * I attach relatively little emotional weight to sex. * I'm generally very good at managing my emotions, so I'm not much bothered by jealousy. * There are many traits I find attractive that couldn't coexist in the same person. (Being bisexual is the extreme case.) And, oh, probably lots more. But poly being a slam-dunk for me doesn't say much about whether other people should adopt it (except for the tiny subset who share most of those traits), so I've been avoiding talking about my own experiences too much. Do you think that's the wrong move?
I paused to think again :-) My instantaneous response idea was to generate a small laundry list of good and bad effects from talking about personal experiences, then pair it down to examples of categories, then use this to say "its really complicated, I don't know". When an interaction is in full-on "adversarial debate mode" I think revealing personal stuff can be a bad thing to do if you accurately predict that the other person is just going to leap on your revelations as evidence for the bias they have been trying to accuse you of having in the course of an ad hominum [http://en.wikipedia.org/wiki/Ad_hominem] and/or ad logicam [http://en.wikipedia.org/wiki/Argument_from_fallacy]. (And unfortunately, the difference between "that's a bias and therefore I win" versus "that's a bias and let's try to overcome it" is small and depends critically on tone.) In this case, for me, I think it was the right move because I ended up seeing it as a "lowering of defenses" (a sort of interpersonal CBM [http://en.wikipedia.org/wiki/Confidence-building_measures]) after I'd implicitly requested that you do so. It would have been horrible of me to use something against you that you had revealed about yourself after I raised the possibility of defensiveness. So um... I think, maybe, yay for us? :-P ::internet high five::
One way that polyamory might not be a kick in the teeth to evolution-- if extended blood families are difficult to recruit for child-raising in the modern world (as seems to be the case), and it's to the advantage of both parents and children to have additional help with child-raising, then the ability to recruit additional adults (whether in sexual relationships or not) should be selected for. And, of course, you can kick evolution in the teeth any time you feel like it, and I think people spend a lot of time doing just that. [1] It's just that you can't get away with it indefinitely. [1] It generally doesn't seem to occur to people in dowry cultures to marry their daughters to people from non-dowry cultures, thus saving the money and still getting grandchildren. I use this as evidence that memes can trump genes fairly easily.
I think it's pretty obvious that monogamy isn't built into human nature, but I object to the post pretty vehemently. Do you have any examples of vehement objections by people who insist that polyamory is 'bad' as opposed to by people who think that bad reasoning is 'bad'? I even said I planned to read the book some day, as it sounded interesting but badly reasoned. However, a short summary of an interesting but badly reasoned book, when the summary itself doesn't comment on the bad reasoning but instead endorses said reasoning, on a rationality blog, seems to indicate to me that the author of the summary needs more practice before they can talk rationally about the subject.
Not specifically, no, nor did I expect to see objections on those grounds. LW generally frowns on unjustified moral absolutes, so far as I can tell. What I did expect to see (and do see) is motivated arguing that ignores my repeated protestations that this is the introductory first post in a sequence. It is certainly true that I erred in mentioning the proposed hypothesis before showing the evidence that had gone into locating it. Yes, my bad. But the intended purpose of the post [http://lesswrong.com/lw/2hq/against_the_standard_narrative_of_human_sexual/2bp8?c=1] was not so obtuse that no one could comprehend it. Why are you so convinced that Sex at Dawn (and my belief in its conclusion) is badly reasoned? You haven't seen the reasoning yet! Would it be an unendurable annoyance if I were to ask you to hold off on forming a conclusion for another 12 hours, while I finish the second post? It won't contain all the evidence I'm planning to present, but there's a chance it'll convince you that there was at least some amount of reasoning involved in this whole process.
What claims are do you think are being made and how do you identify them as motivated arguments?
So you haven't read the book, but you know it's badly reasoned, and anyone who endorses it must not be good at rationality?
Strong disagreements with Pinker are strong evidence for poor reasoning, but much weaker evidence for being wrong. The blog post itself and its comments are pretty compelling evidence for poor rationality skills under stress, most notably the Malthus bit, as people other than myself have mentioned. I endorse lots of books with fairly bad reasoning.
I'm also surprised and confused by Michael Vassar's reaction to this post.
Breaking the responses in two so the discussion can branch naturally :-) The link was intended as a convenient example of a place on the web to find an overview of real world anthropological data relating to sex relations, which could be summarized prior to summarizing conclusions that are probably inferentially far from the audience. The particular details of people's food acquisition habits weren't the focus, merely the general fact of the technology scale and the availability of evidence on the subject. I don't understand why you'd restrict yourself to "nomadic foragers" as opposed to the more general class of "hunter gatherer" who may or may not be nomadic. Is there a reason one is more important than the other? Human "sedentarization" is hypothesized (see here [https://www.uwec.edu/smithbji/Anthro-WMNS%20356/syllabus%20readings/Does%20Sedentariazation%20Promote%20Gender%20Inequality.pdf] for an example of observations contextulized in light of the hypothesis) to correlate with gender discrimination (more mobility goes with less discrimination - IE relatively less coercion of women by men) so I could see how there would be incentives to want to talk about mobile societies where historical arrangements were likely to be somewhat less horrible. An appeal to nature based on nomads is probably going to be a little more egalitarian and pleasant :-)
Agriculture didn't develop until ~8000 B.C. Prior to that point, there were no sedentary hunter-gatherers; mobility offered flexibility, and there was no reason at all to stay in one place. So if we're talking about human evolution, which took place almost entirely before that point, sedentary hunter-gatherers aren't an accurate model of the conditions that shaped our development. I resent the implication that I am making an appeal to nature. However egalitarian and pleasant our nomadic ancestors' lives may have been, I have no desire to imitate them. The best that evolutionary psychology can do is identify certain biological predilections; it cannot and should not attempt to justify them.

In additioned to teageegeepea's points, the Mbuti (who were in the original link I provided that was criticized for having no "nomadic foragers") have villages but no farming. Women help with the hunting and men help with the kids.

Despite being sedentary, anthropologists attribute their balanced sex roles to the fact that women traditionally build the huts, and have something kind of like property rights over them. They have a little bit of polygamy, but it is rare. (Also, they are sometimes treated horribly by political neighbors to the point of being hunted as food. It seems messed up to mention them as "examples for science" without also mentioning their actual interests as human beings.)

I resent the implication that I am making an appeal to nature. However egalitarian and pleasant our nomadic ancestors' lives may have been, I have no desire to imitate them. The best that evolutionary psychology can do is identify certain biological predilections; it cannot and should not attempt to justify them.

"Appeal to nature" is a named fallacy because is super super common, and I didn't even say you were committing it, I said "there would be incen... (read more)

They also engage in trade with nearby agricultural tribes for all kinds of stuff. And once you have stuff, you need a place to put it. And then you start to make a big deal about how it's your stuff and not anyone else's, and then you're not living in the kind of egalitarian forager band that defined the evolutionary environment. I'm resentful of smilies :D (Disclaimer: this is a self-deprecating joke about my own grumpiness.)
According to Jane Jacobs [http://www.overcomingbias.com/2010/04/trade-made-farms.html], cities preceded agriculture. In "Before the Dawn" Wade seems to agree with that theory, as there is evidence that people lived in settled areas for a surprisingly long time without becoming agriculturalists. I was surprised how late agriculture emerged in Japan [http://entitledtoanopinion.wordpress.com/2010/07/11/a-late-start-for-japan/]. A notable example of a group of sedentary hunter-gatherers that American readers may have heard about it middle school are the native americans of the northwest, who relied on the large amounts of available salmon nearby and had "potlatches" featuring the conspicuous destruction of expensive goods.
Jane Jacobs is an urban planner and an economist. While that does not mean that she is wrong, I am not terribly inclined to believe her theory in the absence of any sort of evidence; so far as I can tell, the only justification she offers is a thought experiment. Absent something convincing one way or the other, I'm inclined to consider which came first an open question. Wikipedia [http://en.wikipedia.org/wiki/J%C5%8Dmon_period] cites Japan as having some form of primitive agriculture contemporaneously with the earliest settlements, but its reliability is, as ever, uncertain. I'm not sure how fishing fits into all of this; it may be an important exception to the general trend. In any case, unless settlements preceded agriculture by more than a couple millenia (which Jacobs doesn't seem to claim), anatomically modern humans were still nomads for 95% of their history and nomadic foragers are still our best model of the evolutionary environment.
Jane Jacobs [http://en.wikipedia.org/wiki/Jane_Jacobs] was a writer and activist who did a lot to oppose urban renewal. I suppose you could argue that there were some sorts of urban planning she liked (mixed use, pedestrian-friendly) but on the whole, she supported bottom-up social networks.
My "Jane Jacobs" link was to Overcoming Bias, where it was suggested (by someone other than Jacobs) that sedentary communities preceded agriculture by up to 3000 years, which I suppose would fit your "couple millenia). Your Jomon link said that their pottery is evidence of sedentary living and described its origin as Mesolithic, or "Middle Stone Age" and preceding the Neolithic of agriculture. It also said they were hunter-gatherers and fishermen. It describes them as having "some of the highest densities known for foraging populations", though noting that Pacific Americans were similarly high. When humans left Africa they seem to have hugged the southeast coastline. We can expect that they had boats since they were able to reach Australia and the polynesian islands. So I think fishing was pretty important. Cavalli-Sforza writes of pre-Jomon Japan "A major source of food in those pre-agricultural times came from fishing, then as now, and this would have limited for ecological reasons the area of expansion to the coastline".

It's always puzzled me that evolutionary psychologists only seem interested in relating human social behavior to that of other apes, and therefore can only see the alternatives cited of monogamy or polygyny.

Looking more broadly at animal social systems, there are many other taxa that typically form strong pair bonds, with biparental care, complex social networks outside the pair, jealous mate-guarding males, occasional threesomes where the alpha shows varying degrees of tolerance for the beta, and numerous secret affairs by both sexes. It's called social ... (read more)

You: Me, citing Ryan and Jethá: While gorillas are polygynous and gibbons are monogamous, the other apes (which are, as has been pointed out, more closely related to humans) do not fit either description in the slightest. The problem isn't that evolutionary psychologists look at apes and use them as models of human behavior; the problem is that they look at apes and come up with implausible reasons why humans are different.
A bit off topic: What I'm really confused about is why Bonobos and Chims evolved so differently despite living in similar environments, being closley related and they aren't that isolated from each other either. Does anyone know of any interesting papers on this?
The best I can come up with is this article [http://mbe.oxfordjournals.org/cgi/content/abstract/22/2/297] identifying the timeframe of divergence; I too would be interested in scholarship on the evolutionary pressures responsible. The only factor I'm aware of is the Congo River, which divides the habitats of the two species and may have split their populations. (Neither can swim.)

You've got a good conversation going here. Thanks. Primatologist Richard Wranham has proposed that two related factors contributed to the diverging bonobo/chimp behavior: — far more plentiful food in the bonobo range than in the chimp range and, — chimps compete with gorillas for some of their food sources, while bonobos are isolated from gorillas (and chimps).

This hypothesis would seem to support our argument, in that we find that food supply was generally plentiful for prehistoric populations (with occasional crises), whereas for post-ag populations, food scarcity was a constant problem (as demonstrated by skeletal evidence).

Chris Ryan (co-author of Sex at Dawn)

Welcome to LessWrong! [http://lesswrong.com/lw/b9/welcome_to_less_wrong/] I hope you decide to stay a while.
Pedantic correction: his name is Richard Wrangham with a 'g'. The book is "Demonic Males: Apes and the Origin of Human Violence", co-authored with Dale Peterson. I have a post on it here [http://entitledtoanopinion.wordpress.com/2008/07/02/two-book-reviews/#more-206]. Wrangham has another book, "Catching Fire: How Cooking Made Us Human", which theorizes that the increased calories resulting from food (particularly meat) preparation allowed us to reduce our gut size and increase our brain size, along with introducing pair-bonding. He discusses it in this diavlog [http://bloggingheads.tv/diavlogs/19925].

I also saw the mention of Sex at Dawn in Savage Love and was intrigued. Great post, and I'm looking forward to reading the future ones. I wish I could vote this up more than once.

I'm wondering how this line of thinking would deal with studies that look at human behavior in many different cultures: I know that David Buss in particular has done some survey studies using cultures all over the world, suggesting that social norms don't have much to do with male/female differences in sexuality.

Wrongbot, I wanted to note a disparity between what you say here:

The most recent common ancestor [chimpanzees] share with humans lived somewhere between 3 million and 800,000 years ago.

and what that Wikipedia article on bonobos says twice:

The chimpanzee line split from the last common ancestor shared with humans approximately six to seven million years ago.

Yup, it looks like the consensus is around 6 million. I think I confused the human/chimpanzee split with the chimpanzee/bonobo split, which did seem to happen in that more recent timeframe. Thanks for pointing this out; I've edited my post to reflect the correct figure.

FYI, Dan Savage's podcast, Episode 194, has an interview with Christopher Ryan about the book and its relevance to modern humans.

In light of many of the negative comments and downvotes, I wanted to express thanks for this post, and I hope you continue the sequence.

I think people delude themselves as to how monogamous they actually are (monogamous-but-had-a-fling-once is NOT monogamous. Monogamous-except-that-three-month-period-we-were-broken-up is NOT monogamous. Generally, even monogamous-with-first-spouse,then-monogamous-with-the-new-spouse isn't considered ACTUAL monogamy. And certainly monogamous-by-circumstance shouldn't really count )

And furthermore, I suspect that the sort o... (read more)

even monogamous-with-first-spouse, then-monogamous-with-the-new-spouse isn't considered ACTUAL monogamy.

Considered? Who is the arbiter of such things?

Very well, perhaps that was a bit too strongly worded. Allow me to rephrase that as "there is debate as to whether serial-monogamy constitutes monogamy or is a different form of polyamory"
But is that disagreement about anything more than definitions?
I'm the arbiter of such things.
You shouldn't need group selection to explain that sort of thing. (And I'd be very, very suspicious if you did.) Kin selection [http://en.wikipedia.org/wiki/Kin_selection#Mechanisms] should be more than enough. For what it's worth, anthropologists generally consider relationships to be monogamous if they involve paired-living, long-term association, or joint parenting. Sexual fidelity is not a criterion.

While I agree the evidence is somewhat sparse, I think this is more of an issue of ease-of-reading versus rigor, and I think you've struck a reasonable balance.

I think the central thesis of this is, "The 'classic' view of ev-bio/psych that is modeled on the male earner, female caretaker family structure is probably wrong." If that's the case, your argument and evidence seem fairly solid. If you're going so far as to argue some other specific structure, then you're a bit short on evidence. There is an odd tendency to think that 1955 is the paradig... (read more)

As a rural sort, I'd like to make the point that the full moon is bright enough to read by, and to see some colours.

Townies think the night is dark because they're dazzled by street lights and cars and never have working night vision.

In the absence of artificial light, it only gets truly dark when you can't see the moon or sun.

And even where I grew up, there was always enough light in the sky that the galaxy was difficult to see. Go somewhere truly out of the way and it's like a shining belt all across the sky. That's what real human night vision is like.

From "Sense and Sensibility", by Jane Austen:

"[Sir John Middleton] had been to several families that morning, in hopes of procuring some addition to their number, but it was moonlight, and every body was full of engagements."

I suppose, since this got 5 upvotes, that it isn't just a random non-sequitur. But it looks like one to me.
It seems to be a response to: The point Arfle is making seems to me to be that there is plenty of light available in small villages at night; on nights close to the full moon at least. Personally, I'm not sure that light would be considered useful in successful infidelity anyway, wouldn't darker conditions be preferred?
Not if it's so dark that you can't walk around outside. Infidelity during the evening requires, at a minimum, that one of the people involved walk to the others residence without getting lost or injured.
Walking a short route that you know well is possible even in pitch black. I have, on a couple of occasions, had reason to test this myself, and certainly blind people have reason to test it very often. With starlight to silhouette certain landmarks the possible distance would be much increased, and need for familiarity decreased.
Indeed, it's possible to walk and even bike by starlight or less. I had a bad habit at RIT [http://en.wikipedia.org/wiki/RIT] of biking through the woods by the mess hall late at night; there is no illumination on the footpath and even the stars were hard to see. I could do it without injury because I did it so often.
arfle was illustrating the problem with generalizing about the experiences of our ancestors from our own experiences. (Or so I gather.) Any theory that assumes that the past couple centuries are like the human evolutionary environment in any way is deeply flawed. I (and Ryan and Jethá) would go further and say that the problem really applies to a timeframe closer to a hundred centuries than two, but the idea is the same.
Thanks, that sounds reasonable.
Who posts on LW and cherishes traditional 1950s establishment beliefs about human sexuality?
"Cherishing" those beliefs is quite distinct from holding those beliefs. Even pickup artists operate off of a framework that assumes a fundamental male-earner plus female-nurturer social structure, which is just wrong, since humans were typically tribal and had more extensive social networks than nuclear families. Whether or not people like that system does not relate to whether they think it is of historical/evolutionary significance.

In what sense could Malthus possibly be considered wrong?
I'm a bit confused here. Are you actually denying the theory of evolution in general?

I'm not generally a fan of evolutionary psychology, I'm somewhat uncertain about gender differences in libido (my priors massively favor such differences, but the evidence moves me away from them, leaving me confused), and I'm moderately optimistic about polyamory, but between bad writing style, blatantly stupid conclusions and incoherent argument I wish I could vote this down more than once.

Could you qualify those criticisms? What do you dislike about my writing style? Which conclusions are blatantly stupid? Which arguments do you find incoherent?

Personally, I found that there wasn't a sufficiently clear distinction between when an argument was part of the "standard model", when it was made in the book, and when it was your opinion.

Also, this sentence:

There are four major research areas supporting the standard narrative that Sex at Dawn identifies in Chapter 3 as underpinned by Flintstoned reasoning, which collectively lead to the conclusion that "Darwin says your mother's a whore." (Ryan and Jethá, 50)

... is very confusing, and trying to be witty doesn't help. Just look at the grammar:

A supports B that C identifies as underpinned by D, which leads to the conclusion that "E says F" (G).

I mean, what the fuck? Is the conclusion that "Darwin says your mother's a whore." or "your mother's a whore."?

I understood the sentence after three or four rereadings, but I certainly wouldn't put it in the hall of fame of "clear and concise writing".

Not my best work, I agree. I've edited the post to make that section clearer.

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