(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.
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.
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.)
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.
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.
(Ryan and Jethá, 231, referring to research by Kilgallon and Simmons)
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.
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.
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)
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.)
"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)
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'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)
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:
and what that Wikipedia article on bonobos says twice:
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)
Considered? Who is the arbiter of such things?
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."
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.
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:
... is very confusing, and trying to be witty doesn't help. Just look at the grammar:
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".