The most common human mating pattern is monogamy, the next most common polygyny (one husband, two or more wives), then polyandry (one wife, two or more husbands). Tibet had both polyandry and polygyny. I know of no society where group marriages (two or more of each) were common but examples have existed, such as the Oneida commune in 19th century New York and smaller groups in the 1960's and thereafter.
Under current U.S. law monogamy is the only form of marriage legally recognized but there are no longer legal bars to de facto polygamy; all three forms, although uncommon, exist. It is interesting to speculate on what forms polygamy might take in the future in modern developed societies and why.
Two features of modern technology make polygamy, in particular polyandry, more pracrical than in the past: reliable contraception and paternity testing. Men want to know whether a child is theirs. In the past, the only was to have had exclusive sexual access to the child's mother. Now all it takes is a reliable lab. A woman with several husbands could bear children by all of them, with each husband knowing which children are is. The selective use of contraception would make it possible to decide in advance which men would father children when.
One function of marriage is to produce and rear children, another is sexual pleasure. One woman is physically capable of satisfying several men and some women might enjoy doing so. Reliable contraception makes it more practical than in the past to delink sex from marriage entirely and, to a considerable extent, it has happened. But polygamy, by keeping sex within a small group, would reduce the risk of sexually transmitted diseases and might make better use of the emotional concomitants of intercourse. Modern technology provides ways in which parents can choose to raise the odds of producing a son; the result in some societies is a substantial m/f imbalance in the population.1 Polyandry would make it possible in such a society for the excess men to have wives and families.
In a modern society polygyny, historically more common, could provide a solution to a different problem. Back when legalized abortion and readily available contraception first became hot political issues, a major argument in favor of both was preventing the birth of unwanted children, meaning children born to unmarried mothers. Both legalized abortion and readily available contraception now exist in most developed societies. They have been accompanied by the opposite of the predicted effect, a sharp increase in the number of children born to single mothers.
One possible explanation2 is that, in a world where intercourse was likely to lead to pregnancy, most women were unwilling to sleep with a man unless he was prepared to offer support to any resulting offspring, typically by being engaged or married to her. Breaking that link meant that women who did not want children and did enjoy sex were willing to engage in it without such a guarantee, sharply worsening the bargaining position of women who wanted sex, children, and support. Some of those who could not find husbands chose to produce children without them. Polygyny would offer some of them the more attractive alternative of a husband who wanted children. For such men it provides more sexual variety than monogamy, more emotional security and less medical risk than promiscuity. Also more children.
So far I have been looking at marriage primarily from the standpoint of sex and children. It is also an institution for the production of household services and the sharing of income. In one traditional form of monogamy there was a fairly sharp division of labor, with the wife running the household and the husband working outside it to bring in income. The combination of low rates of infant mortality, meaning that a family that wants to end up with two children need only produce two, and modern technology — washers and dryers, dishwashers, microwave ovens, food bought already prepared — has converted household production from a full time to a part time job, save for a few years when a child requires full time parental attention. The usual modern response is for both partners to earn income outside of the household, possibly with one of them, usually the wife, taking some years off for child rearing. An alternative, possibly superior, would be a family of three or more, with one member specializing in running the household and caring for the children.
In most past societies, children grew up with multiple siblings. With the lower birth rates of modern developed societies, most have zero, one, or at most two. A large family might be a better environment for acquiring social skills. If so, pooling the children of two or three women in a single family might be a plus.3
All of this is mostly speculation. Over the years I have occasionally encountered people who were part of polygamous families of one sort or another but have never done much research into how or why they were organized. There is a literature, largely online, on polyamory, but what I have seen of it deals more with structuring the emotional relationships than with organizing production, child rearing, and associated activities.
Comments welcome, especially from those with first hand experience.
Evidence
Research on the effect of polygamy on wives and children has produced little useful evidence for polygamy in a modern, developed society. Most was done in Subsaharan Africa, the one part of the world where polygamy (specifically polygyny) is common.4 Those societies are much poorer than ours, different in other ways as well.
A second problem is that, since we have no controlled experiments, it is hard to tell whether observed correlations between polygyny and outcomes for children represent an effect of marital structure on children’s outcomes or an effect of some third variable on both. An article on Côte d’Ivoire, for example, finds that children of polygynous parents get less education than children of monogamous parents. It also finds that monogamous parents are richer and better educated, which seems an adequate explanation of why their children get more education.
A third problem is that authors may start with an opinion about polygamy, positive or negative. The clearest negative example I came across was an article which ended by citing biblical passages critical of polygamy. In the other direction there was a critical summary of the literature pretty clearly intended to show that it was not clear that polygamy had a bad effect on children.
For the effect of various forms of non-monogamous child rearing in our society there is a good deal of anecdotal evidence online from the now-adult children, some of whom are happy with the outcome, some not,5 but I could find nothing better than that.
Science Fiction
Polygyny provides a solution to a situation with more women than men, polyandry to one with more men than women. Both situations have existed in the past, the latter in some countries at present. What if you had both?
That possibility occurred to me after reading a discussion online of the high m/f ratio in engineering schools.6 Imagine a future society with well defined marital niches. Male star ship crew, facing voyages several years long, want to marry women who can go with them. Women modified to underwater life want husbands similarly modified. More men than women want to voyage to the stars, more women than men to the sea floor. The situation is stabilized by polyandry for the former, polygyny for the latter.
That is science fiction but one can imagine something similar in our society in the immediate future. For any individual man, only a minority of women are suitable mates.7 Going back to the case of engineering schools, suppose someone suitable for that profession very much prefers a mate with similar talents — and there are not enough of them. Polyandry could sove the problem. Some people want children, some don’t. If more women than men want children, polygyny would let all of them have both children and husbands. Repeat, with suitable applications of your imagination, for other sorts of men and women who might prefer a matching mate.
If, for the reasons sketched in the first part of this essay, modern conditions make both polygyny and polyandry more practical than in the past, we may be getting more of both.
The Elephant in the Room
I have so far ignored what some readers may consider the crucial issue: sexual jealousy. Most men don’t want the woman they sleep with to sleep with other men, most women similarly. If that preference is hard wired it creates a barrier, although not an absolute bar, against any form of polygamy.
If, on the other hand, male sexual jealousy exists at present as a mechanism for reliable paternity, female as a mechanism to reduce the risk that paternal resources will be diverted to another woman’s children, reliable paternity testing and enforceable contracts for support may make both unnecessary.
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The old way of doing so was selective infanticide, the improved modern version selective abortion. Technologies are now becoming available, although not yet entirely reliable, for selective conception.
Akerlof and Yellin, "New Mothers, Not Married: Technology shock, the demise of shotgun marriage, and the increase in out-of-wedlock births" The Brookings Review, Fall 1996 Vol. 14 No. 4, Pages 18-21.
Also see George A. Akerlof, Janet L. Yellin, J. L., & Michael L. Katz, "An Analysis of Out-of-Wedlock Childbearing in the United States," 111 Q. J. Econ. 277 (1996)
For a classic description of life in a large family, see Cheaper by the Dozen. For an attractive modern picture of a large (monogamous) family, follow Anna Krupitsky on Facebook.
Some also among Israeli Bedouins.
Online links to accounts by children:
https://www.reddit.com/r/AskReddit/comments/ivbcrl/comment/g5r6bpu/
https://www.reddit.com/r/AskReddit/comments/ivbcrl/children_of_poly_relationships_what_was_it_like/?rdt=53524
https://medium.com/heart-affairs/when-kids-are-raised-in-a-polygamous-household-c7f36cc83344
The marital prospects, from the woman’s side: “The odds are good but the goods are odd.”
In my case, someone I could discuss ideas with without feeling as though I needed a translator.
In some of the poorest parts of India, brothers share a wife[1]. One brother stays home with the woman, working in agriculture for a year or so, while the other moves to a larger city thousands of miles away to work as a manual laborer where pay is better. Then the brothers switch places.
After reading your post, I realized this arrangement also ensures that if the woman becomes pregnant, they know fairly reliably who the father is. The physical distance also ensures that there is no sexual jealousy.
I learned this from someone who had moved to the city from such an arrangement. He said this practice essentially ensures that the woman (who is often married at the young age of 14 or older) does not have affairs. It is seen as preferable to be intimate with a husband's sibling than with someone outside the family. Additionally, others in the village know the woman is "protected," so they are less likely to pursue her. Secondly, children are taken care off even if the father knows they are not his, because after all they are still his own blood (through brother). Grandparents too have no reason to discriminate against grandkids.
[1] This is not a common practice because my source for this is anecdotal information but confirmed by occasional news article throwing light on these sort of things.
1) Do you think that the decline in monogamy and rise of polygamy is to do with changes in technology, or to government interference in marriage law? Since the 1970s, divorce courts have ruled consistently against men even when a woman violates her marital vows, such as by committing adultery. Adultery is essentially a form of fraud and theft -- a reneging on a contract where the one owes chastity to the other. Typically, there was some punishment, even perhaps physical punishment, for women who committed adultery. The result is that government has essentially made marriage, in the traditional sense, illegal. It is illegal for a woman to take a vow of chastity in the USA which is legally enforceable. I am not advocating or denying this system of traditional marriage. Here is a substack article I wrote about it: https://romanviolin.substack.com/p/marriage-is-illegal?https://substack.com/home/post/p-143174733?r=1dzuvw&utm_campaign=post&utm_medium=web
2) The other major factor you are missing is the fact that reproduction, biologically, is much more difficult for women than for men. A man who wants to have hundreds of children, theoretically, can. A woman simply cannot have very many children, and by the time the number gets up to three, four, five, and more the household work does become a full time job. The check to female reproduction is biological. The check to male reproduction is social. The hard part is finding a wife, but after consummation the woman does most of the work (biologically)! In a sense, men have many more children to "give" than women do. If every man was allowed to repopulate at his preferred rate, he would produce an entire village full of children.
Thus, the result of normalizing and legalizing polygamy is not likely to be a greater increase in overall sexual satisfaction. The result is likely to be that a small number of men marry all the women, and that most men are pushed out of the sexual marketplace entirely. This has already happened to a considerable degree.
3) In a polygamous society there is no "we" -- the male and female unit -- which produces children and "owns" the family. Under monogamy, both the man and the woman did all the work -- biological, economical, social and otherwise. Under polygamy, is the "we" all the parental members of the family? Let us say there is a polygamous relationship with two men and three women. Will each man be the 1/2 property owner of all the children produced by his wives (regardless of paternity), or will he fully own only his children and have no fatherhood role toward the rest? Will his income than be docked according to which children are his? Then multiple children who are siblings will have different socioeconomic statuses despite living in the same house depending on who their father is. Additionally, is it to be expected that men and women care for all children produced by the family and not prefer their own children? I think that the preference for one's own children is pretty inborn into us as well, especially into women.
At a certain point, polygamously, doesn't the "we" just become all of society? Why can't a million people just sign a contract saying we all are married polygamously now, and these children are all our children, owned jointly? Then, we will designate some institution to take some of everyone's income and this institution will be responsible for raising all the children. Indeed, we are halfway there already -- to full sexual socialism.
I hope these comments provide food for thought. Always an interesting read, Mr. Friedman.