Mothers and Others: The Evolutionary Origins of Mutual Understanding (Belknap Press) Hardcover – April 30, 2009

This book should be read by anyone with an interest in human evolution but especially by those with an interest in human uniqueness. Dr. Hrdy writes beautifully, is vigorous in her attention to empirical evidence, but she is also willing to speculate about the conditions that fostered uniquely human traits. Among the most obvious of these traits are our extended lifespans, prolonged childhoods, big brains, perspective taking (mind reading) or intersubjectivity, language use, cumulative culture, mutual understanding, norm formation and enforcement, altruistic punishment, and moral judgment. The list could of course go on but what concerns Professor Hrdy more than these individual traits is describing the conditions or preconditions fostering these co-evolving traits. As she notes, the most common explanation for our pro-social traits is group competition but, as she argues, such competition is common among other primates, especially the Great Apes, and the question becomes "why us and not them?" She does not discount completely the role of group competition but argues that by far the most important reason that humans display their uniquely pro-social suite of traits is that "novel [child] rearing conditions among a line of early hominins meant that youngsters grew up depending on a wider range of caretakers than just their mothers, and this dependence produced selection pressures that favored individuals who were better able at decoding the mental states of others, and figuring out who would better help and who would hurt" (p 66).Hrdy argues that cooperation more than competition accounts for our unique traits, although the two are hardly incompatible.

Dr Hrdy speculates that within the genus Homo, Homo erectus may well have exhibited cooperative breeding--that is, groupmates or alloparents other than mothers tended to children, including nonkin--and that they may have been emotionally modern. By 1.8 million years ago Homo erectus was almost as large and as large brained as Homo sapiens, and, although male australopithecines were twice as large as females, males and females among Homo erectus were only slightly more dimorphic than Homo sapiens. Whatever the precise date for the emergence of cooperative breeding within our line, humans, unlike any of the Great Apes, have cooperative breeding and this fact Dr Hrdy maintains is the precondition that made the remarkable human suite of traits possible.

In these brief comments I have stressed the speculative features of Dr. Hrdy's argument because they are both the most novel and interesting elements. Let me stress in conclusion, however, that the author attends scrupulously to data and evidence, so even if one is less convinced than I am about the theoretical claims she makes, the book will instruct the reader on every page, especially if it is read slowly.

Brad Lowell Stone

"Mothers and Others" is a worthy successor to Hrdy's 1999 "Mother Nature," which provided a sociobiologist's analysis of the relationship between mothers and children. This book examines cooperative childcare or in the human species. This adaptation in humans is unique among great apes, although corporative breeding occurs elsewhere in the animal kingdom.

Hrdy sticks fairly close to her thesis, that humans are unique in the way we employ "alloparents," that is, other caregivers in the nurture of our children, and especially in the vast variety of arrangements that seem to work. In descending order, the most important relationships are the mother's mother, sisters, and daughters. Among the important males are of course the father, but also to a surprising degree other men who might be the father, and brothers.

One of the most unique thing about human beings is the variety of relationships. In other species, if a father is useful in raising children, he is pretty generally useful, such as the father fish which let their mouths be used as a nursery. In people, however, the rules vary from culture to culture and even family to family. It is a matter of, whatever works.

The take-home truth is that human babies are tremendously expensive to raise. They take forever to mature. In the days before we became civilized they were highly vulnerable to predators and to starvation. The child had a vastly superior chance of survival if more than one person was responsible for taking care of him. Cooperation was also a superior use of resources: one person could watch two or three kids, giving other mothers the freedom to cultivate crops or gather food.

Continuing a theme from her first book, Hrdy emphasizes that building relationships is a two-way street, and that evolution has obviously favorite children who are good at building relationships. They know how to be cute, how to babble, how to look deeply into a caregiver his eyes, how to be demanding, coy, or whatever it takes to seduce other humans into taking care of them. And in doing this, they become quite Hrdy calls "emotionally modern." Children become good at reading the intentions of other people, a characteristic at which humans are vastly better than our ape cousins.

Hrdy repeats findings that one reads elsewhere about the timeframe in which human beings developed. It boils down to this. A few million years of slow evolution through the Pliocene after we parted company with the chimpanzees. Then, with the emergence of homo erectus at the beginning of the Pleistocene, about 1.8 million years ago, more rapid development of this emotional modernity. Of course, there is little fossil evidence - mostly speculation. However, the fossil record does show the beginnings of tool use, the use of fire, and gradually increasing brain size evidence. Then, only 200,000 years ago or so, homo sapiens emerged, as did language, modern brain sizes, the modern races of man, and the spread of mankind out of Africa.

Hrdy gently dispatches the notion of a primordial patriarchy. Since their mothers kin were so useful in raising her children, matriarchal societies were more likely than patriarchal, although here as always we are an amazingly versatile species. She offers a now common argument that patriarchy probably became a dominant social form after the advent of agriculture, when men needed to band together to into armies to defend what they had amassed, at which point paternity became an issue because there was property worth inheriting.

Most of Hrdy's examples are taken from well studied groups of primitive humans in Africa and the Amazon. They offer the most probable models of human society as it existed tens and hundreds of thousands of years ago. She asks some interesting questions. Infants today are certain to get enough calories to survive regardless of the society in which they live. However, she asks, is it not quite likely that they did not get the emotional support that they need to develop into fully socialized human adults? Is our society changing, perhaps degenerating, as children are raised in environments in which they have less emotional security than their ancestors?

Both of Hrdy's books should be required reading well outside the field of sociobiology. They throw a bracing dash of cold water on the highflown theories of political scientists, religious advocates, educators, feminists and others who purport to have discovered great truths about how to socialize and educate the human animal.

Mothers and Others: The Evolutionary Origins of Mutual Understanding (Belknap Press) Hrdy's book is the most exciting and revolutionary book I have read on the subject of human evolution. Her main thesis is that prior to Homo erectus our ancestors developed a facility for infant and child care by many group members, allowing the mother to attend to other tasks and, over time, infants to evolve larger brains and childhood into a longer, richer learning period. This thesis is well backed by extensive studies regarding apes, primates, other mammals, and human hunting and gathering societies.

This is a very important piece of work that expands and clarifies Hrdys line of reasoning in her first book, Mother Nature. She presents such a huge amount of research into the socioemotional and evolutionary underpinnings of empathy and nurturing behavior that it is sometimes a little hard to view the forest behind all the trees. Although this is definitely not a book geared towards the novice it is well written and a must-read for everyone working in the field of anthropology. Btw, the photos are gems in their own right.