Mother Nature: A History of Mothers, Infants, and Natural Selection

Read an Excerpt

The death of a child is the most awful occurrence parents can imagine. Fortunately for most of those reading this book, childhood death is a rarity. Unlike Nisa, they live in privileged regions of the globe, at least for the time being, and enjoy an unprecedented standard of living. Nine hundred and ninety-four of every thousand babies born in the United States survive infancy. Yet even though the odds of keeping infants alive have improved astronomically, the chances that a woman in a postindustrial society will die without descendants have not changed that much. In the Sacramento Valley of California, where I live, 40 percent of all grown women who died between 1890 and 1984 left no surviving offspring. But the reasons so many womenin the Kalahari and California populations died childless are quite different. In twentieth-century California, many of the women never married. Others could not, or consciously decided not to, have children, or else decided to give birth to only a few. Almost all infants born survived, so that the average number of children per woman (1.6) was close to the number actually born. The circumstances surrounding motherhood have never been more different. Yet, as I will show in this book, from contemporary countries in which women live in a state of ecological release, no longer constrained by having to forage enough food each day to stay alive and with a broad range of reproductive options, to other parts of the world where they are less fortunate, women are constantly making tradeoffs between subsistence and reproduction that are similar in outline.



Quality vs. Quantity

Depending on the marriage customs in the culture shebelongs to, a woman may or may not get to choose the father of her children or the time in her life when she first becomes pregnant. Depending on prevailing values, she may or may not treat her sons and daughters, her firstborn versus her last-born, exactly the same way.Yet, by and large, she will decide how much of herself, her time, energy, and love, she will invest in each child.The father has similar choices, although he may make quite different decisions. In the past, such decisions had a direct effect on both a mother's own survival and that of her children. Throughout most of human existence, to be an infant without a mother, or a child without older kin, was to suffer a life-threatening disadvantage. To have become the ancestress of any one of us today, a mother would have had to succeed in rearing at least one offspring to breeding age. In turn, that offspring would have had to produce surviving heirs. This is why quantity has rarely been the top priority for a mother. The well-being of her children and their quality of life, usually inseparable from her own, were primary. When fidelity to his mate means that a man's reproductive success is identical to his only wife's, he is more likely to share her preference for quality over quantity. Otherwise, and especially if he does not intend to invest in his offspring, a man may simply seek to breed with as many women, and hence sire as many offspring, as he can. It is from such ancestors that we inherit our maternal emotions and decision-making equipment. Underlying tensions between males striving for quantity and females for quality (a simplification I will clarify later) are as old as humanity.Yet this tension has risento the surface and become more conspicuous than ever in the ecological circumstances of a modern world in which women have unprecedented choices.

For example, when young women are given a choice between having children and improving their lot in life, most opt for the latter. At first glance, such a finding seems completely antithetical to predictions from evolutionary theory. In the crass coinage of my Darwinian worldview, success is measured in terms of "fitness," genetic representation in succeeding generations. Access to more resources should translate into people having more children, not fewer. Certainly there is massive documentation that throughout recorded history, quite a few men opted for more.

Kings, emperors, and despots--who had the power to do so--filled their seraglios with fertile women. Feudal lords insisted on droit de seigneur with virgins marrying within their domains, while some American presidents have used their office (literally, the oval one) to enjoy assignations. However, the emphasis on quantity that holds true for male potentates (and surely we don't call them that for nothing) does not hold true for mothers.

Around the world, there is a tendency for people who are better off to have a lower birthrate. This tendency is evident among peasant women in India as well as women in industrialized societies. Witness the declining birthrates in contemporary Japan, or the below replacement fertility that has long characterized modern France and Italy and is increasingly true in established populations in the United States. Wherever women have both control over their reproductive opportunities and a chance to better themselves, women opt for well-being and economic security over having more children. For many, leaving children every day while they work is a matter of survival, the only way mothers can support their families, or the only way they can secure a decent future for offspring. (A big difference between modern industrial societies and people who live by foraging is that children who must not only be fed but clothed and educated become more costly with age, not less.)

But survival does not explain all the choices. Third world peasants just making a skimpy living on small plots of land will trade the clean air and safer environment of the countryside for squalid urban shantytowns with their glimmer of economic opportunity, accepting the deaths of some children from respiratory or gastrointestinal infections in exchange for some prospect of a "better" life. Far more privileged women also may opt for self-realization over reproduction, forgoing motherhood to become artists, pilots, or scientists.

At first their choices appear counter to evolutionary expectations, until we recall that mothers evolved not to produce as many children as they could but to trade off quantity for quality, or to achieve a secure status, and in that way increase the chance that at least a few offspring will survive and prosper. This is why a closer look at what late-twentieth-century women are doing reveals behavior that is not so much "unnatural" as behavior that is in conflict with conventional expectations--all the myths and superstitions about what women are supposed to want.

So how did people in the Western world come to conceptualize female nature and "motherhood" the way we do?