"There is a theoretical debate...over the evolutionary status of human polyandry and whether it is truly an adaptation....We argue that marriage (or pair-bonding) is the adaptation."
Starkweather & Hames, "A Survey of Non-Classical Polyandry" (Human Nature 23:12, June 2012)
Humans are an effectively polygynous species; that is, the reproductive fitness variance of males exceeds the reproductive fitness variance of females. However, our degree of polygyny is not particularly high among primates; we have significant adaptations for pair bonding and monogamy. Daly & Wilson say (Homicide, p. 143) that "we are the products of a mild but sustained polygynous competition."
What about polyandry? Marriage relationships between a single female and multiple males has been understood to be extremely rare among humans, both based on anthropological evidence and for sound biological reasons; Daly & Wilson cite the classical source, Murdock's Ethnographic Atlas, for the proposition that "a tiny minority [of human societies] practice polyandrous marriage." Starkweather et al. mention that for the 1967 sample Daly & Wilson are citing, only seven societies are identified as practicing polyandry out of 1,167 societies in the sample. A tiny minority, indeed!
A popular blank-slatey denial of both polygyny and monogamy adaptations (and, some argue, the adaptation of pair bonding in general) has emerged in recent years, known as Sex At Dawn. I have not deigned to read this book, but I am informed and on that basis believe that its authors argue that humans are basically happy love monkeys cruelly forced into the strictures of monogamy by agricultural patriarchy.
As a happy love monkey, I am, emotionally, extremely sympathetic to this ludicrous line of hogwash. Yes, human males are much bigger than human females, we mate face-to-face, males invest heavily in their children and exhibit violent sexual jealousy, and basically the picture is one of monogamy shading into polygyny - but what about our huge penises, huh? What could they be but beautiful twat squeegees? And what about the fact that cuckolding is the second most common heterosexual interest in pornography, after (the unquestionably adaptive characteristic) youth?
What theory truly accounts for all the facts about humans and their mating systems? This theory must not be a blank slate, must not be happy love monkeys (no adaptations after bonobos? really?) and must not be pure virtuous monogamous/polygynous females (else why the twat squeegees?). It must account for pair bonding, but also for occasional extrapair matings - for complicated but biologically sensible intrasexual and intersexual competition.
There is no reason that a polyandrous society might not fall within the realm of possibilities of such a theory - given the right environmental or population constraints and the right social institutions. Indeed, in the article quoted at the beginning of this post, Starkweather and Hames find 53 societies that practice polyandry outside the classical societies surveyed by Murdock. While still a "tiny minority" of human societies, polyandry is a sensible model for the tiny minority of societies experiencing certain constraints.
What is the single biggest determinant of a society going polyandrous? It is, say Starkweather and Hames, a male-skewed operational sex ratio. That is, when there are way more males than females in a society, polyandry is a likely solution to that problem. This is true whether the operational sex ratio is temporarily skewed (by an unusual war), or permanently so (by, say, the practice of whale hunting). Temporary polyandry follows temporarily skewed sex ratios; stable polyandry follows stably-skewed sex ratios. There is evidence that the overall operational sex ratio in the Western world and China has become mildly male-skewed in recent decades; even this relatively mild skew has had measurable, culture-dependent effects.
Do we know of any communities that have massively male-skewed sex ratios?
Yeah, that would be us.
Who are "we"? We might identify as rationalist nerds. Many of us have IQs a couple-few standard devs above average, and many of us enjoy some form of Autistic Spectrum Disorder. Many of us read LessWrong, or are at least aware of LessWrong enough to pretend not to read LessWrong. Many of us pass through Senior House or East Campus at MIT; others, through Blacker House or Ricketts House at CalTech. We are particularly likely to chew nicotine gum despite never having smoked cigarettes (which only scratches the surface of our drug use).
To some limping extent, we form a semi-endogamous community. How sex-skewed are we? Taking LessWrong as a sample of whatever we are, according to the 2011 survey, we are 89% male. An operational sex ratio of 204 males to 100 females, as found in Netsilik children, is considered extremely high, and is highly determinative of polyandry. Our LessWrong operational sex ratio would be 1056 males per 100 females.
This is gender skewing beyond what would be expected based on mere IQ; in the Scottish sample, there were 203 girls and 277 boys in the 140 band of the IQ test, for a skewed-but-not-ludicrous operational sex ratio of 136 boys per 100 girls. Whatever we are, we are not selecting in merely for intelligence, but likely also for other factors that are heavily dependent on sex.
As someone who lettered in both math team and cheerleading, polyandry has been a reality of my dating life since I was 16. (I am Presently in a Monogamous Relationship Okay.) Polyamory was already a buzzword at MIT in the mid-1990s, but my girlfriends and I didn't need anyone to tell us that we could have whoever we wanted PLUS whoever else we wanted, PLUS set all the rules, and if anybody didn't like it, they were mean, jealous crybabies. This is pretty much totally unfair, and I guess our emotional response to this unfairness was something like, "well, patriarchy sucked, payback's a bitch."
However, despite the unfairness, it is not at all clear that the polyandrous polyamorous system in place in many elite bohemian communities is undesirable for the males involved. Indeed, many males in this system actively seek to promote it; this comment from Eliezer Yudkowsky is one of my favorite examples:
The following is a public service announcement to all women who naturally like at least some shy nerds.
If you are (1) polyamorous and (2) able to directly ask men you find attractive to sleep with you (instead of doing the sheep dance where you freeze motionless and wait for them to approach) - or if you can hack yourself to be like that without too much effort - it is vastly easier than you imagine to acquire an entire harem of high-status and/or handsome nerds.
(For some but not all nerds, this may require that you be reasonably attractive. Most nerd girls I know are reasonably attractive and think they are not. So if you think that you're overweight and hideous and yet oddly enough nerds spend a lot of time talking to you at nerd parties, this means you are pretty.)
This concludes the public service announcement.
In addition to the high male-skewed operational sex ratio, we have many things going for us as a community in terms of determinants of successful polyandry. For one thing, our males, I offer, seem to experience less sexual jealousy than average human males. Whether this is mostly a result of their biological characteristics, or mostly a result of cultural norms against jealousy, it does seem to be effective in suppressing most open expression of hostile jealousy.
Also, we are generally socially broken and pathologically interested in a lot of other things besides social monkey crap. (I mean this as a very high compliment.) We are still monkeys, but we are able to get a lot of our happiness, status, and belonging from sources other than a monogamous pair bond. Since we have often failed to develop healthy social instincts, we are not hampered by these instincts as much as the regular monkeys seem to be.
However, the reason I wrote this is to caution against a stupid, blank-slatey ideal of natural polyamory, and to challenge the community to think harder and create institutions that can make polyandry work and solve its inherent problems.
The 53 societies Starkweather et al. identified as polyandrous were identified as such based on a marriage-like institution: rights and obligations toward each other and toward any children of the union, along with some degree of limitation of sexual access to others outside the union. Right now, it doesn't look to me like nerd polyamory has almost any institutions or expectations by the community about partners' rights and duties toward each other. Any kind of right or duty is looked at askance; each relationship group is expected to hammer out its own institutions from scratch.
It's amazing that this is controversial, but I argue that relationship norms are part of our cultural package, and we rely on them both to be secure and to feel secure in our relationships. It's demonstrably not stupid to think that polyandry could be part of our relationship norms; but it is, I think, stupid to think we don't need any norms or institutions at all.
While we do seem to be low on male sexual jealousy, humans as a species tend to exhibit violent male sexual jealousy; wife-killing is the least culturally variable portion of homicides, and violent sexual jealousy is a frequent motive in male-male homicides as well (see, e.g., Daly & Wilson, Homicide, "The Logic of Same-Sex Conflict"). This represents only the visible tail of jealous violence. While discouragement of jealousy is probably awesome as a sexual norm, I suspect that the outright DENIAL of the existence of jealousy may be harmful. We haven't had a community murder yet that we know of, but what are we doing to make sure it never happens? And what can we do to prevent not just the expression of jealousy, but the painful experience of jealousy? How can we avoid ending up like those people on Proles Behaving Badly?
There are two related problems that may be exacerbated by polyamory: low-status male celibacy and sliminess. While polyandry probably does a better job of managing male intrasexual conflict over females than monogamy in a sex-skewed community, those unfortunate males in the lowest status quadrant are frequently left partnerless; even a Zipgirl membership is a status good when there are 1056 males for every 100 females, and our community is not somehow magically invulnerable to hypergamy. Sliminess is the problem of guys (not just low-status guys) sliming all over women when there aren't clear boundaries preventing such sliminess. I am certain this is a problem in monogamous communities, but I suspect it is even more of a problem when even the "taken" girls are not really "taken." We have not solved this problem as a community, and if anything, it makes us less attractive to much-needed women. Sexual attraction is not egalitarian, and our norms must reflect this. Can we be fair without being egalitarian? Can we make our women happy without making our low-status men miserable? I have rarely seen an acknowledgement that these problems even exist (except from the Men's Rights folks, with whom we have some overlap, like it or not), let alone proposals for how to deal with the problems.
A solution to our skewed sex ratio, perhaps even more powerful than polyandry, is chosen bisexuality (what some call sexuality hacking). Can some men who feel heterosexual but want to be bisexual increase their sexual response to other men? How can they go about doing that? Not much has been written on this. While male sexuality is no doubt less plastic than female sexuality, evidence of highly bisexual societies like the ancient Greeks imply that male sexuality has possibilities unrealized in our present world. Can our community tap these possibilities?