Joseph Henrich, the evolutionary psychologist who testified against polygamy at the Canadian polygamy trial has a new paper out on the topic. I’ve engaged with his statements on the topic before, so I was curious what he had to say in peer review. It isn’t so much different from what he had to say on as a witness in court, and I have some of the same sorts of problems with it.
See whether you can spot them. From the press release:
“Our goal was to understand why monogamous marriage has become standard in most developed nations in recent centuries, when most recorded cultures have practiced polygyny,” says UBC Prof. Joseph Henrich, a cultural anthropologist, referring to the form of polygamy that permits multiple wives, which continues to be practiced in some parts of Africa, Asia, the Middle East and North America.
“The emergence of monogamous marriage is also puzzling for some as the very people who most benefit from polygyny – wealthy, powerful men – were best positioned to reject it,” says Henrich, lead author of the study that is published today in the journal Philosophical Transactions of the Royal Society. “Our findings suggest that that institutionalized monogamous marriage provides greater net benefits for society at large by reducing social problems that are inherent in polygynous societies.”
Considered the most comprehensive study of polygamy and the institution of marriage, the study finds significantly higher levels rape, kidnapping, murder, assault, robbery and fraud in polygynous cultures. According to Henrich and his research team, which included Profs. Robert Boyd (UCLA) and Peter Richerson (UC Davis), these crimes are caused primarily by pools of unmarried men, which result when other men take multiple wives.
“The scarcity of marriageable women in polygamous cultures increases competition among men for the remaining unmarried women,” says Henrich, adding that polygamy was outlawed in 1963 in Nepal, 1955 in India (partially), 1953 in China and 1880 in Japan. The greater competition increases the likelihood men in polygamous communities will resort to criminal behavior to gain resources and women, he says.
According to Henrich, monogamy’s main cultural evolutionary advantage over polygyny is the more egalitarian distribution of women, which reduces male competition and social problems. By shifting male efforts from seeking wives to paternal investment, institutionalized monogamy increases long-term planning, economic productivity, savings and child investment, the study finds. Monogamy’s institutionalization has been assisted by its incorporation by religions, such as Christianity.
Monogamous marriage also results in significant improvements in child welfare, including lower rates of child neglect, abuse, accidental death, homicide and intra-household conflict, the study finds. These benefits result from greater levels of parental investment, smaller households and increased direct “blood relatedness” in monogamous family households, says Henrich, who served as an expert witness for British Columbia’s Supreme Court case involving the polygamous community of Bountiful, B.C.
Monogamous marriage has largely preceded democracy and voting rights for women in the nations where it has been institutionalized, says Henrich, the Canadian Research Chair in Culture, Cognition and Evolution in UBC’s Depts. of Psychology and Economics. By decreasing competition for younger and younger brides, monogamous marriage increases the age of first marriage for females, decreases the spousal age gap and elevates female influence in household decisions which decreases total fertility and increases gender equality.
Unlike many press releases, there is a copy of the paper itself attached. Kudos to Henrich and/or his institution for that. I also have to agree with Henrich and his coauthors that the evils of polygyny that he lists are evil and are common to many polygynous cultures. I’m not certain, however, that the evidence presented by this paper supports monogamy as an adaptive solution to those evils.
The press release does a good job of describing the social ills reviewed within the paper. Those social ills are, in fact, lessened in monogamous societies. However, they are also lessened in societies that don’t view women as property to be acquired solely for the purpose of producing children. When you compare monogamous cultures to each other, instead of simply comparing monogamous to polygynous cultures, those cultures that treat women as autonomous adults do better on many if not all of those measures.
That’s not a problem for this paper, of course, until you understand that the cultures from which the vast majority of his data come also score very, very low on the idea that women are autonomous beings instead of purchaseable baby machines. Suddenly we are faced with a competing theory of a practice that may have made one culture more successful than another. Was it monogamy or female agency that swept the world (to the extent that there was true cultural competition instead of the genocide of global colonialism)?
Given that, is monogamy (in its various forms) an adaptive cultural construct in itself? Or it is largely a tag-along, an idea that has had close association with another idea that we already know is adaptive? This paper draws the first conclusion, even though it doesn’t present the evidence to distinguish between the two.
For most of us, this distinction will be trivial. We’ve been enculturated to serial monogamy, and it’s a fully workable system for most people. It’s even more workable given the fact that our social institutions are set up to support it. Beyond that, building romantic and sexual relationships that meet our cultural expectations for such relationships is complicated. A minority of people have the resources for managing relationships that contain more than one partner at a time.
That minority still exists, however. Not every autonomous adult is best suited to monogamy. And that’s when it becomes important to sort the causes from the effects of various forms of culturally recognized relationships. If we determine that one type of relationship is clearly superior and deserving of official support, we place additional burdens on those who build other types of relationships.
Of course, we could simply say that this is just one paper. It answers one question. On the other hand, Henrich has not restricted himself to this one paper. Both here and in his testimony in the polygamy trial, he has argued strongly against providing any support to nonmonogamous relationships. His behavior is adding to the marginalization of polygamists. Going by his testimony, going by this paper, his research is insufficient to support his behavior.
Henrich, J., Boyd, R., & Richerson, P. (2012). The puzzle of monogamous marriage Philosophical Transactions of the Royal Society B: Biological Sciences, 367 (1589), 657-669 DOI: 10.1098/rstb.2011.0290
Photo by firemedic58. Used under a Creative Commons license.