Sarah Hrdy is an American anthropologist who has devoted much of her career to studying parental care in primates, and she has ruffled quite a few feathers along the way. In her one of her first books, The Langurs of Abu: Female and Male Strategies of Reproduction (1977), she described the langurs as practicing infanticide. That description led one (male) colleague to snipe,
“Sarah Hrdy’s monkeys are deranged.”
Hrdy had seen male langurs attack and kill infants sired by rivals, so that they could induce estrus in the females and then mate with them. Female langurs had their own defenses against marauding males. When a male took over a troop, pregnant females would fake being in estrus and let him mate with them. The male would then believe himself to be the father of her offspring and protect them accordingly.
In her next book, “The Woman That Never Evolved“ (1981), Hrdy argued that female primates had developed many strategies for coping with dominant males, including forming alliances with other females. She also maintained that Darwin’s belief in sexually passive females stemmed from relatively new social mores that most primates, including some humans, did not abide by. Hrdy also described polyandry, the practice of mating with more than one male, as advantageous to females and their young. Most or all of the males that had mated with a given female were likely to believe that the resultant offspring was theirs.
Cooperative Breeding and Parental Care
1999’s “Mother Nature” was a synthesis of her earlier work, and it also described why humans developed infanticide and polyandry in the first place. Hrdy views humans as cooperative breeders who need a village to raise a child.
Throughout history, humans have used allomothers to help with parental care. Despite the name, an allomother can be male or female, and they are usually a relative of the mother who helps her raise a child. Women need allomothers to successfully rear children, and Hrdy also argues that the lack of allomothers in modern human societies has caused such problems as child abandonment. If a mother feels overwhelmed and helpless, she may well decide to abandon her child— or worse. In an interview, Hrdy described the case of a woman who had drowned her five small children in a bathtub. Hrdy argued that probably would not have happened if the young mother had had some kind of support.
The Limits of Maternal Love
Hrdy also maintains that the so-called maternal instinct doesn’t exist. A female primate’s capacity for parental care depends largely on her access to resources like food, shelter and a supportive mate.
Women do indeed bond with their infants, and those bonds can have a biological basis, like certain hormones. Those bonds, however, can be overridden by the wrong set of circumstances.
Contrary to what many people believe, maternal love is conditional, and that’s especially true with humans. Human women are virtually the only female primates that commit infanticide, which is generally the province of males in other primate species.
Furthermore, infanticide is not as rare as people want to believe. Hrdy describes times and places in which infanticide was extremely common. A village in Bolivia was plagued by both war and extreme poverty during the 1930s, and practically all the women in it killed their newborn children. Far from being heartless or insane, these women recognized they did not have the resources to give good parental care to their children. Hrdy reported that, after their situation had improved, many of the women went on to have children who they treated very well.
Extended Families Versus Nuclear Families
2009 saw the publication of “Mothers and Others: The Evolutionary Origins of Mutual Understanding“, in which Hrdy returns to the topic of allomothers or alloparents. She argues that the development of extended families had a profound influence on human evolution.
Cooperative breeding helped make it possible for families to successfully rear children that took two decades to reach maturity. Hrdy argues that human beings are supposed to live in extended family groups and that the nuclear family is an aberration that does not provide sufficient support for its members. Consider what often happens if one parent in such a family dies or is incapacitated. In an extended family, the surviving adults would help both the children and their parent(s). An extended family shares the duties of parental care, thus reducing the odds of any one adult becoming overwhelmed.
Unlike Hrdy, most psychologists and authors on books about parental care take the nuclear family for granted, a stance she disagrees with.
One of Hrdy’s colleagues, Hillard Kaplan, calculated that a human child needs 13 million calories of nutrition during the first 18 or 20 years of its life. That is far more than a single woman or couple could provide on their own, so humans must have evolved to be part of extended families.
The assumption of the nuclear family’s primacy
Hrdy points out that the assumption of the nuclear family’s primacy has affected research. Most research done on families simply compares married couples to single parents, rather than comparing either one to an extended family. Researchers have also not compared the various types of extended families to each other. That means there is so far no way of determining which familial arrangements might be optimal for raising children: parents working with grandparents, siblings raising children together, or some other arrangement. Determining which arrangements would be most beneficial for parents and children would only help society in the long run.