Has the relative bargaining power between men and women been shaped by our evolutionary history? Economist Paul Seabright explains how, in his book The War of the Sexes: How Conflict and Cooperation Have Shaped Men and Women from Prehistory to the Present (2012).
Millions of years ago our ancestors began to colonise what Seabright terms “a very risky evolutionary niche: the long childhood”. This needed more cooperation between the sexes in order to ensure the survival of the offspring, and sex became not merely reproduction but also a cooperative venture.
We all know the profound differences between male and female sex cells. Women’s are large, scarce and relatively expensive to make. Men’s are small, abundant and cheap to manufacture. Because of the relative scarcity of women’s eggs, and their costliness once fertilised, women have to be selective about the source of the sperm. A woman carries and nurtures the foetus in her body for over nine months. Once the baby is born, she has to feed and protect the child for a long time afterwards. She does not want to waste her opportunities on unsuitable men; they have to be screened out. So we have female selectivity on the one hand and male persistence on the other hand.
What were the large brains for?
From Charles Darwin onwards, sexual selection – for reproduction – has been seen as distinct from natural selection – for survival. Large brains are for perception, cooperation, reciprocity and the cognitive challenge of keeping track of mutual obligations. These are functions that might be thought of as for natural selection.
Long childhoods are related to large brains. Because a baby’s skull only just fitted through the mother’s pelvis, birth had to precede brain and body development. Consequently, complex social arrangements became necessary, for it was costly to feed and protect the child who was dependent for so long. Both mother and child needed meat and calories to support the growing brain. Foraging for this diet required more ambitious and cooperative hunting and gathering arrangements. The longer childhood, even in hunting-gatherer groups, meant greater female cooperation with men.
But the human brain has additional capabilities. The mind can produce works of art (music, painting, sophisticated stories) as well as complex language skills and wit and humour. These brain functions are not for survival and are therefore not thought of as part of natural selection. Many evolutionary biologists and evolutionary psychologists see these functions instead as being for sexual selection; that is, for reproduction. (For example, see: Geoffrey Miller’s book, The Mating Mind: how Sexual Choice Shaped the Evolution of Human Nature). Matching (or sexual pairing) based on creative courtship behaviour is, it is argued, a key part of sexual selection in human mental evolution.
“That the peacock can survive
How might this work? Complex human courtship behaviour can be viewed as part of the creative human mind, and arose for the same reason that male peacocks have such gorgeous tails – for mating purposes. That the peacock can survive and be healthy – despite its enormous rear end – indicates its good genes. In displaying its tail it signals its potential to be a fine mate.
Male and female brains
The differences between male and female hominid brains are very small and there are negligible sex differences in the “g-factor” underlying IQ test performance. This does not imply that sexual selection is irrelevant, but rather that both sexes are choosy – and that there is mutual mate choice. Brains are good indicators of nutritional state and general health: they represent 2 percent of body weight but consume over 25 percent of adult metabolic energy (60 percent in infancy).
This similarity between male and female hominid brains suggests that they faced equally sophisticated cognitive challenges throughout almost all of our evolutionary history. As Seabright argues:
“On this view, the subordinate and dependent condition of women that has characterised relatively recent centuries cannot have obtained for most of the time since we diverged from the chimpanzees and bonobos.”
How did bargaining power alter?
What happened to relative bargaining between males and females with the introduction of agricultural cultivation? The bargaining power of women was to weaken. Why was this the case? Danish economist Ester Boserup (1970) distinguished between two forms of soil cultivation to prepare the ground for planting in her book, Woman’s Role in Economic Development.
The first form is the labour-intensive shifting cultivation, which uses hand-held devices such as the hoe and the digging stick. The second form is the more capital-intensive plough cultivation, which requires upper-body strength to control the plough. Consequently, the latter form of cultivation gave men a comparative advantage relative to women and led to a division of labour in which men worked in the fields while women specialised in work in and around the home. This gender-based division of labour then gave rise to a culture which codified women’s place as being in the home.
Testable predictions of this theory are that cultures based on plough cultivation are characterised by less equal beliefs about gender roles. Some recent economic studies empirically test the hypothesis that different agricultural practices influenced the historical gender division of labour, and that they also contributed to the evolution and persistence of gender norms.
One example is the 2012 paper “On the Origins of Gender Roles: Women and the Plough” by Alesina, Giuliano and Nunn. The study shows that individuals, ethnicities and countries whose ancestors engaged in plough agriculture are characterised by greater gender inequality today, as well as by lower female participation in a range of activities outside the domestic sphere.
The codification or culture that a woman’s place is solely in the home has, since the middle of the 20th century, been losing force in many parts of the world. We are shifting to a post-industrial world in which the bargaining power of women is again changing. In many societies we are moving towards greater equality and cooperation between the sexes. Will we eventually see, everywhere on our planet, an equalisation in the bargaining power of men and women? Let us hope our descendants do not have to wait too much longer before finding out that this is indeed the case.
Alison Booth is Professor of Economics at the Australian National University and an ANU Public Policy Fellow. Her academic research is in labour and behavioural economics, and she is the author of The Jingera Trilogy.