'The WEIRDest People in the World' gets polygyny wrong
Anthropologist Joseph Henrich has a new book out, The WEIRDest People in the World: How the West Became Psychological Peculiar and Particularly Prosperous. I have previously written a number of articles touching favorably on his work, in relation to monogamy, leadership, and cultural evolution, though I have also contested his, in my view, overemphasis on cultural group selection as an explanation for the social structure of the Ilahita Arapesh horticulturalists of New Guinea. I have not yet finished Henrich’s latest work, however it contains a section discussing polygyny (Chapter 8, pgs 256-263) that I believe is sufficiently flawed and misleading to warrant detailed criticism.
One thing I have always appreciated about Henrich’s work is his focus on the importance of culture for understanding human behavior, and much of what I have read in his new book thus far follows that tradition, such as his rich description of the social norms characteristic of societies with patrilineal clans (pgs. 104-115). I was surprised, however, to see that his account of polygyny is a very simple evolutionary psychology model. He argues both men and women have an “evolved psychological push to polygynous marriage” (pg 259), yet the evidence he provides points to the severe limitations of this argument, and in some ways severely undercuts it.
Henrich writes that, “In the most comprehensive study, 90 percent of hunter-gatherer populations around the globe had some degree of polygynous marriage, while just 10 percent had only monogamous marriage.” However, this manner of dichotomizing full monogamy and any degree of polygyny is a highly debatable way of conceptualizing this, and stems from the coding decisions made by anthropologist George Murdock back when he created the Ethnographic Atlas and the Standard Cross-Cultural Sample [the EA and the SCCS are large datasets consisting of geographically and culturally diverse societies of multiple subsistence types coded on numerous variables]. Murdock and anthropologist Suzanne Wilson coded societies with less than 20% of marriages being polygynous as ‘limited polygyny’, yet they could have just as easily coded these societies as being ‘mostly monogamous’, in which case it would be clear most societies are mostly monogamous, and Henrich’s account would likely have to be framed quite differently.
Cross-cultural codes for the SCCS, from Murdock & Wilson (1972).
Indeed as Henrich notes, “Of the societies with polygyny, about 14 percent of men and 22 percent of women were polygynously married.” Meaning the majority of marriages across ‘societies with polygyny’ are in fact monogamous. If, then, the data shows that monogamy is the most common form of marriage cross-culturally, by a wide margin, why should these data be framed as humans having an “evolved psychological push to polygynous marriage,” rather than an ‘evolved psychological push to monogamous marriage’?
Of course, different researchers can prioritize different domains, and if polygynous marriage is extant across cultures, despite usually not being the most common form of marriage, then the ‘puzzle of polygynous marriage’ remains. Accepting this, is an ‘evolved psychological push to polygynous marriage’ the best explanation for the existence of polygyny cross culturally?
Henrich writes that, “The best move for a particular woman in a hunter-gatherer society might be to become the second wife of a great hunter instead of being the first wife of a poor hunter; this helps guarantee that children get both excellent genes and a steady supply of meat (a valuable source of nutrition).” While this may be true in some contexts, one of the papers Henrich cites actually demonstrates that this is an insufficient and often poor explanation for polygyny cross-culturally.
One paper Henrich cites on the prevalence of polygyny is Frank Marlowe’s 2003 paper ‘The Mating System of Foragers in the Standard Cross-Cultural Sample’. Marlowe found among hunter-gatherer societies in the SCCS “The percentage of polygynous women is higher where gathering contributes more to the diet (r= .477, p= .008, n= 30) and lower where fishing contributes more to the diet (r= –.550, p= .002, n=30), which is where males contribute the most.” This may seem puzzling until you realize what the mechanisms supporting polygyny tend to actually be. Marlowe found that, “Among foragers as well, there is a higher percentage of polygynous women where female marriages are arranged (r= .502, p= .009, n= 26). Assault frequency is also correlated with percentage of polygynous women (r= .672, p= .001, n= 22).” This is consistent with other work noting the ubiquity of arranged marriages across hunter-gatherer societies, as well as a recent replication from 2018 demonstrating the association between polygyny and assault frequency, as well as polygyny and arranged marriages, across societies in the SCCS.
As Marlowe himself summed it up in his 2003 paper cited by Henrich, “Among all 186 societies in the SCCS, there is greater polygyny where female marriages are arranged but not where male marriages are arranged (Marlowe, n.d.), suggesting that marriage arrangement is a form of male coercion and a way parents can benefit by supplying the most influential males with brides.”
Henrich does discuss arranged marriages and their coercive elements in other contexts, writing that among societies with patrilineal clans, “Norms about arranged marriages empower patriarchs to strategically use their daughters’ marriages to nourish their clan’s network of alliances and relationships.” (pg 107), and there is a strange disconnect when he notes among the Wathaurung of Australia that, “Men arranged marriages for their daughters or sisters, often when they were children or even infants. As in most hunter-gatherer societies, men could marry polygamously, with prestigious hunters and great warriors sometimes accumulating five or even six wives, leaving lesser men with no wives and few prospects.” (pg 60). This makes it quite odd that he never seems to connect arranged marriages to the practice of polygyny cross-culturally when this association is directly noted in one of the key papers he cites and clearly prevalent in the ethnography he discusses.
Henrich assumes polygynous marriages reflect an ‘evolved psychological’ bias on the part of both sexes towards such marriages, but as mentioned above polygynous marriages cross-culturally can often be a coercive arrangement where powerful males arrange such marriages for themselves or their kin (as Henrich noted among patrilineal clans, without making the connection to polygyny). From the male perspective, they can also be motivated by economic concerns just as much or even more than sex or companionship, as I discussed in detail here. As I noted in that piece, anthropologists Charles Hart and Arnold Piling write that among the Tiwi hunter-gatherers of Australia,
The most concrete symbol of Tiwi success was the possession of surplus food, for this not only permitted its possessor to make gifts to others and throw large parties for which he picked up the check, but also gave him lots of leisure time to devote to social and political life. Since a man required a large number of women in his work force if he was to build up a surplus of food, in the final analysis it was control of women that was the most tangible index of power and influence. Women were the main currency of the influence struggle, the main “trumps” in the endless bridge game.
Notably Tiwi practices of polygynous marriages could not possibly be attributed to any ‘evolved psychological push’ on the part of women towards such marriages, as they, like the Wathaurung, practiced infant bestowal, where young girls would be promised in marriage arrangements orchestrated by their male kin, often before they were even born—a not altogether uncommon form of marriage arrangement across some hunter-gatherer societies. They also had strong social norms requiring every woman to be married, and as a consequence practiced compulsory widow remarriage.
Consistent with the economic incentive for polygyny, among the Asmat hunter-gatherers of New Guinea, at marriage a man would gain access to the highly valued sago patches that his wives inherited through their matrilines. His wives would provide the labor necessary to process the sago enabling him to throw feasts and gain status, similar to the Tiwi example where female labor is a path to increasing male status. Anthropologist Bruce Knauft goes into detail on the coercive and economic dimensions of Asmat marriage practices, writing that,
Polygyny and control of female labor in sago production were a significant dimension of male status differentiation, and in cases of polygynous marriage, second wives "may be little more than drudges" unless they were sisters to the first wife (Eyde 1967:194; cf. Trenkenschuh 1982a:46). Wife-beating was assessed by Eyde (1967:192) to have been quite common among central Asmat, and he says, "only where a wife-beating becomes near-murder, or actually results in murder, will her brothers intervene." He documents four cases that came to his attention in which men in fact murdered their wives. Unmarried women could be beaten by their fathers or brothers for promiscuity (ibid. :220).
Even beyond more coercive arrangements and economic motives, polygyny can be highly influenced by cultural norms in other ways, such as through sororal polygyny (where co-wives are sisters). Among the Dobe Ju/'Hoansi hunter-gatherers of the Kalahari, anthropologist Richard Lee found a relatively small percentage of polygyny, as well as a polyandrous union “In a sample of 131 married men in 1968, 122 (93 percent) were living monogamously, 7 (5 percent) were living polygamously (6 with 2 wives, 1 with 3), and 2 men (2 percent) were living in a polyandrous union, sharing 1 woman.” And of these, “Three of the 7 cases were sororal polygyny, while in 4, the co-wives were unrelated.” Among the Kaska hunter-gatherers of British Colombia, marriages were generally arranged, monogamy was the norm, and polygyny and polyandry co-existed in relation to economic needs, with polygyny always being sororal. Anthropologist John Honigmann notes that,
Monogamous families were most common. Few men could afford to support as many as two wives and the children they produced. Polygyny was sororal in type. Even a widower had trouble securing permission to marry a woman other than his deceased's wife's sister, parents-in-law showing particular possessiveness about a man renowned as a hunter. To bring an unrelated woman into the family constituted a signal for the first wife to quit her husband and go home. No bride service attended marriage to a subsequent wife. Polyandry appears to have been restricted to old men who were unable to hunt sufficiently to support their families.
Note further that here it is the parents-in-law in particular preferring a good hunter, consistent with the common cross-cultural practice of ‘bride service’ across many hunter-gatherer societies, where the husband or prospective husband provides goods and services to their in-laws for a period of months or years at the start of marriage (or sometimes longer). As the Kaska practiced bride service for the first marriage, but not for second wives, this preference for sisters if polygyny occurred makes even more sense, as they were coming from the same household, where the man was likely already providing for his in-laws (notably the Dobe Ju/'Hoansi also practiced bride service). This makes a great deal of sense when you think of how marriages are often an economic arrangement between families across many traditional societies, rather than projecting the modern WEIRD norm and assuming such marriages are the result of autonomous individuals engaging in free choices. Henrich himself actually gives a great description related to this in the chapter on ‘WEIRD Families’, writing that,
In pre-Christian Europe, as in much of the world until recently, marriage customs had evolved culturally to empower and expand large kin-based organizations or networks. Marital bonds establish economic and social ties between kin-groups that foster trade, cooperation, and security. To sustain such ties, long-term marital exchanges are necessary…In patrilineal societies, senior males—the patriarchs—administer these ongoing spousal exchanges and thus use the marriage of their sisters, daughters, nieces, and granddaughters to cement relations with other kin-groups and nourish important alliances. Arranged marriages thus represent a key source of patriarchal power (pg 167) [emphasis added].
It’s unfortunate he doesn’t connect this pattern to the practice of polygyny, and instead offers a simplistic free choice model in the polygyny chapter.
These social institutions demonstrate the importance of considering cultural norms (and other dimensions of socioecology) for understanding both polygyny and monogamy, as well as other cross-cultural practices, as Henrich has effectively argued previously and in other parts of his new book.
For more on polygyny cross-culturally, see my piece for Areo Magazine ‘How Coercive is Polygyny?’