Beginning with anisogamy, the differences between the sexes have important consequences on social systems - Kitchen & Beehner (2007)
In the volume Kinship and Gender (2010), anthropologist Linda Stone writes that, “Today anthropologists generally agree that cases of true matriarchy do not exist in human society, and that they most probably never have.” If you start from the position that human cultural diversity is essentially unlimited, then this presents something of a puzzle. When looking across cultures, it’s clear that societies with patriarchal social institutions are very common, so why don’t we see comparable matriarchal institutions?
In a recent article for Quillette, I tried to explain why sex differences in lethal violence are found seemingly everywhere, with men consistently committing more lethal violence than women do. I will not rehash the entire argument here, but will simply note that this pattern is entirely predictable in light of classic sexual selection theory. Males produce small, relatively mobile gametes while females produce large, less mobile gametes. Female mammals engage in more parental care than males, while male mammals have a greater potential reproductive output – as they are not constrained by gestation and lactation time – and can thus benefit more from competing directly for mates. Much violent conflict between men can be explained as competition for mating opportunities, or competition for status and/or resources that may net them more mating opportunities.
These very basic sex differences in reproductive strategies have important implications for political systems. In anthropologist Martin King Whyte’s study on The Status of Women in Preindustrial Societies, he looked at sex differences in political participation across 93 nonindustrial societies of various subsistence types (hunter-gatherer, horticulturalist, pastoralist, agriculturalist) from all over the world. Whyte found that in 88% of societies, only men were political leaders, while in another 10% of societies some political leaders were women; however, men were more numerous and/or more powerful.
In only 2 societies (2%) were women coded as having roughly equal power in political leadership as men; the Bemba of southern Africa and the Saramacca, who are descendants of African slaves in South America. However, behavioral ecologist Bobbi S. Low notes in Why Sex Matters (2015) that among the Bemba, women “had power over women's affairs but had only informal influences on men's issues,” and among the Saramacca, while women “appeared to be able to make the same decisions as men,” they “held power less often.”
In describing the results of his study, Whyte noted that, “These findings fit the generalization accepted by most anthropologists that there are no known cultures in which women are generally dominant over men, whereas there are quite a few in which the reverse is true.”
Even within relatively egalitarian societies, men seem to be disproportionately represented among individuals participating in prestige activities. In The Lifeways of Hunter-Gatherers (1995), anthropologist Robert Kelly writes that, “...even the most egalitarian of foraging societies are not truly egalitarian because men, without the need to bear and breastfeed children, are in a better position than women to give away highly desired food and hence acquire prestige.” In Kinship and Gender (2010) Linda Stone cites the Vanatinai of New Guinea as an example of a gender equal society. Yet in her study on the Vanatinai, titled Fruit of the Motherland: Gender in an Egalitarian Society (1993), anthropologist Maria Alexandra Lepowsky writes that,
“…because of women’s specialization in childcare and in life-giving activities more generally, and because of men’s identification with the destructive powers of sorcery and killing…more men than women are highly active in ceremonial exchange and mortuary ritual and thus gain area-wide renown and influence.”
Note the theme here; women are more constrained by caregiving duties while men are more able, and/or more willing, to seek prestige. Not unexpectedly, in Whyte’s study he also found that in every society in his sample, women did more household work than men did.
While I think you can explain these cross-cultural sex differences in political participation in light of individual fitness interests, other scholars have sometimes attributed it to pressures related to intergroup competition throughout our evolutionary history. Primatologist Richard Wrangham and psychologist Joyce Benenson argue that, “male humans and chimpanzees were selected for effective use of male-male alliances as a result of their vulnerability to lethal intergroup violence.” It can be hard to separate individual fitness concerns from more group oriented pressures, as coalition formation can be in an individual male’s fitness interests. Among a chimpanzee population at Gombe National Park in Tanzania, participation in coalitionary aggression was found to increase a male’s reproductive success.
This connection is illustrated clearly in a paper fittingly titled, ‘Male chimpanzees exchange political support for mating opportunities’ (2007), which demonstrated that while the highest status male of the Kanyawara chimpanzee community at Kibale National Park in Uganda had the greatest reproductive success and monopolized access to females, he rewarded the males who supported him in conflicts by tolerating their mating efforts. We can see the connection here between adaptive strategies for pursuing status among males, as well sex-specific coalition formation in the face of strong competition (for direct mating access, status, or resources), whether intra- or intergroup. Frans de Waal makes the relevant point in his book Chimpanzee Politics (1982),
“The contrast between the sexes cannot be denied. Stated in the simplest terms, the one is protective and personally committed, the other is strategic and status oriented. The picture looks familiar? Am I allowing myself to be governed by my prejudices, or is this once again a striking similarity between chimpanzees and humans?”
Finally, I’d add that the main pressures I see related to male dominance in political participation are 1) high status males having greater access to mates, and greater access to other desirable resources, and thus being incentivized to seek more political power, and 2) the disproportionate caregiving burden that falls on women. In modern, industrialized contexts, as we see technology reducing domestic labor, high income families able to outsource caregiving duties to low-wage (often immigrant) labor, and the demographic transition changing traditional patterns of high-status males having greater reproductive success, it’s not surprising to see greater female participation in politics and prestige-occupations, and I would expect this to continue in the future. The one unanswered question I have is if male variance in reproduce success will increase due to greater numbers of males dropping out of the workforce and staying out of the labor and mating markets. In such a scenario you could still have a relatively small cohort of ambitious males dominating the political process and prestige occupations for a long time.
 Wrangham, R.W. & Benenson, J. 2017. Cooperative and Competitive Relationships Within Sexes. in Chimpanzees and Human Evolution (ed. by Muller, M. et al.) Cambridge: Harvard University Press.
 Gilby, I.C. et al. 2013. Fitness benefits of coalitionary aggression in male chimpanzees. Behavioral Ecology and Sociobiology
 Duffy, K.G. et al. 2007. Male chimpanzees exchange political support for mating opportunities Current Biology