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|Tue, 03-03-2009 - 3:56am|
In a Helpless Baby, the Roots of Our Social Glue
By NATALIE ANGIER
Published: March 2, 2009
In seeking bipartisan support for his economic policies, President Obama has tried every tip on the standard hospitality crib sheet: beer and football, milk and cookies, Earth, Wind and Fire.
A baby may look helpless. It can’t walk, talk, think symbolically or overhaul the nation’s banking system. Yet as social emulsifiers go, nothing can beat a happily babbling baby. A baby is born knowing how to work the crowd. A toothless smile here, a musical squeal there, and even hard-nosed cynics grow soft in the head and weak in the knees.
In the view of the primatologist Sarah Blaffer Hrdy, the extraordinary social skills of an infant are at the heart of what makes us human. Through its ability to solicit and secure the attentive care not just of its mother but of many others in its sensory purview, a baby promotes many of the behaviors and emotions that we prize in ourselves and that often distinguish us from other animals, including a willingness to share, to cooperate with strangers, to relax one’s guard, uncurl one’s lip and widen one’s pronoun circle beyond the stifling confines of me, myself and mine.
As Dr. Hrdy argues in her latest book, “Mothers and Others: The Evolutionary Origins of Mutual Understanding,” which will be published by Harvard University Press in April, human babies are so outrageously dependent on their elders for such a long time that humanity would never have made it without a break from the great ape model of child-rearing. Chimpanzee and gorilla mothers are capable of rearing their offspring pretty much through their own powers, but human mothers are not.
Human beings evolved as cooperative breeders, says Dr. Hrdy, a reproductive strategy in which mothers are assisted by as-if mothers, or “allomothers,” individuals of either sex who help care for and feed the young. Most biologists would concur that humans have evolved the need for shared child care, but Dr. Hrdy takes it a step further, arguing that our status as cooperative breeders, rather than our exceptionally complex brains, helps explain many aspects of our temperament. Our relative pacifism, for example, or the expectation that we can fly from New York to Los Angeles without fear of personal dismemberment. Chimpanzees are pretty smart, but were you to board an airplane filled with chimpanzees, you “would be lucky to disembark with all 10 fingers and toes still attached,” Dr. Hrdy writes.
Our capacity to cooperate in groups, to empathize with others and to wonder what others are thinking and feeling — all these traits, Dr. Hrdy argues, probably arose in response to the selective pressures of being in a cooperatively breeding social group, and the need to trust and rely on others and be deemed trustworthy and reliable in turn. Babies became adorable and keen to make connections with every passing adult gaze. Mothers became willing to play pass the baby. Dr. Hrdy points out that mother chimpanzees and gorillas jealously hold on to their infants for the first six months or more of life. Other females may express real interest in the newborn, but the mother does not let go: you never know when one of those females will turn infanticidal, or be unwilling or unable to defend the young ape against an infanticidal male.
By contrast, human mothers in virtually every culture studied allow others to hold their babies from birth onward, to a greater or lesser extent depending on tradition. Among the !Kung foragers of the Kalahari, babies are held by a father, grandmother, older sibling or some other allomother maybe 25 percent of the time. Among the Efe foragers of Central Africa, babies spend 60 percent of their daylight hours being toted around by somebody other than their mother. In 87 percent of foraging societies, mothers sometimes suckle each other’s children, another remarkable display of social trust.
Dr. Hrdy wrote her book in part to counter what she sees as the reigning dogma among evolutionary scholars that humans evolved their extreme sociality and cooperative behavior to better compete with other humans. “I’m not comfortable accepting this idea that the origins of hypersociality can be found in warfare, or that in-group amity arose in the interest of out-group enmity,” she said in a telephone interview. Sure, humans have been notably violent and militaristic for the last 12,000 or so years, she said, when hunter-gatherers started settling down and defending territories, and populations started getting seriously dense. But before then? There weren’t enough people around to wage wars. By the latest estimates, the average population size during the hundreds of thousands of years of human evolution that preceded the Neolithic Age may have been around 2,000 breeding adults. “What would humans have been fighting over?” Dr. Hrdy said. “They were too busy trying to keep themselves and their children alive.”
Dr. Hrdy also argues that our human ancestors became emotionally modern long before the human brain had reached its current average volume of 1,300 cubic centimeters, which is about three times the size of a chimpanzee brain — in other words, that we became the nicest apes before becoming the smartest. You don’t need a bulging brain to evolve cooperative breeding. Many species of birds breed cooperatively, as do lions, rats, meerkats, wolves and marmosets, among others. But to become a cooperatively breeding ape, and to persuade a bunch of smart, hot-tempered, suspicious, politically cunning primates to start sharing child care and provisionings, now that took a novel evolutionary development, the advent of this thing called trust.
To explain the rise of cooperative breeding among our forebears, Dr. Hrdy synthesizes an array of new research in anthropology, genetics, infant development, comparative biology. She notes that recent research has overturned the longstanding insistence that humans are a patrilocal species, that is, with women moving away from their birth families to join their husbands. Instead, it seems that young mothers in many traditional societies have their own mothers and other female relatives close at hand, and who better to trust with baby care than your mom or your aunt? New studies have also shown the importance of postmenopausal women to gathering roots and tubers, the sort of unsexy foods that are difficult to disinter and lack the succulent status of, say, a freshly killed oryx, but that just may help feed the kids in hard times. Other anthropologists have made the startling discovery that children have entertainment value, and that among traditional cultures without television or Internet access, a bobble-headed baby is the best show in town.
However cooperative breeding got started, its impact on human evolution was profound. With helpers in the nest, women could give birth to offspring with ever longer childhoods — the better to build big brains and stout immune systems — and, paradoxically, at ever shrinking intervals. The average time between births for a chimpanzee mother is about six years; for a human mother, it’s two or three years. As a result of our combined braininess and fecundity, humans have managed to colonize the planet; exploit, marginalize or exterminate all competing forms of life; build a vast military-industrial complex all under the auspices of Bernard Madoff and with one yeti of a carbon footprint, and will somebody please hand me that baby before it’s too late. http://www.nytimes.com/2009/03/03/science/03angi.html?8dpc=&pagewanted=all