The Village Effect: How Face-to-Face Contact Can Make Us Healthier and Happier (22 page)

Randy Jirtle is a Duke University biologist who has demonstrated that cloned mice with exactly the same genome can develop fur coats of dramatically different colors, depending on what their mothers or their grandmothers ate before they were born. Even before they were conceived, their ancestors’ behavior mattered. We used to think that identical twins had exactly the same foundational material—the same eye color, the same height, even the same sense of humor and IQ scores. Yet according to
work such as Jirtle’s, we now know why identical twins might not develop the same physical and psychological traits. Despite sharing the same genome, diverging personal histories might produce diverging characteristics.

Sitting on top of the genome, the epigenome (the Greek prefix
epi
means “on”) transforms the way DNA is expressed without changing anything about the DNA itself. Traditional evolutionary mechanisms are slow. It would take many generations for a mutation that was perfectly adapted to global warming to thrive, for example. But epigenetic transformation is fast, allowing the genome to “respond to the environment without having to change its hardware,” Jirtle explains. If we think of the genome as the computer’s hardware, then “epigenetics is the software. It’s just so darn beautiful if you think about it.”
³⁹

It
is
beautiful, if only because we now have a way to understand how something as simple as holding an infant against your chest can transform the baby’s developing synapses. This close contact provides the baby with clues about whether it’s a safe and predictable world. But if something goes wrong and adversity interferes with the parent–child pas de deux, that rupture in human contact communicates to the vulnerable infant that its system should be on high alert. Epigenetics translates environmental threats into chemical signals that activate—or silence—the gene clusters that govern the baby’s metabolism and endocrine systems. These gene clusters tell the baby how to apportion its available calories or how to prepare itself to face danger. In other words, parenting influences how a baby’s genes are expressed. If that doesn’t make new parents more anxious than they already are, consider this: there’s evidence that a baby’s early warning systems are triggered in utero, based on chemical signals secreted by a stressed-out mom. And that pregnant mother’s brushes with anxiety or adversity can be passed on to the next generation.

THE DUTCH HUNGER WINTER

The Dutch Hunger Winter, from November 1944 to May 1945, occurred when a German food embargo combined with a particularly harsh winter. The disastrous result was that thirty thousand people starved to death in less than six months. The Dutch women who were pregnant at the time (and who survived) gave birth to unusually small babies. That wasn’t a big surprise. What was shocking was that the fetuses’ experiences of deprivation in utero—especially if the mothers faced famine during the first two trimesters of the pregnancy—led to high rates of diabetes, cardiovascular disease, and cancer when these babies, who are now in their sixties, grew up. Not only that, the children and even the grandchildren of women who had been exposed to famine in utero shared their mothers’ and grandmothers’ high-risk profile. They had very small babies themselves, with endocrine systems preset to secrete gobs of stress hormones. In other words, they inherited the effect of their grandmothers’ privations and could pass them on to their own offspring. These epigenetic effects could still be detected six decades after the famine.
⁴⁰
The fetuses’ hunger had stamped food insecurity onto their genes.

When it comes to deprivation, generational effects are also gender effects. Feast and famine patterns in northern Sweden from the 1800s, discerned by studying meticulously kept community health records, show that a grandmother’s diet could predict how long her granddaughters lived. Meanwhile, a grandfather’s prenatal or childhood brushes with food scarcity predicted the lifespan of his grandsons. If, after a shortage, food suddenly became plentiful and Grandpa could gorge to his heart’s content (especially during middle childhood, a slow growth period), his sons and grandsons were at much higher risk of dying of diabetes and heart disease. Perversely, lack of food during other chapters of the grandfather’s life conferred some protection from stress-related diseases on his heirs.
⁴¹
This was true of the Sardinian centenarians we met in
Chapter 2
. Along with their ancestors, they experienced well-timed lean periods that, combined with the lifelong TLC offered by their friends and family, allowed them to live long enough to blow out more than a hundred birthday candles.

WHAT’S LOVE GOT TO DO WITH IT?

The McGill University neuroscientist Michael Meaney was gesticulating in front of a PowerPoint slide at an international psychology conference in Toronto. The slide showed mother rats nursing several tiny purplish pups. Meaney pointed out how some of the dams were hunched over as they nursed their babies, rounding their backs to create a space for the little ones to latch on and move freely underneath. Other dams weren’t hunched. They remained flat-backed, their teeny-weeny violet-tinged pups hanging off their teats. Still other rat mothers were lying on top of their nursing babies, nearly suffocating them. Not all rat mothers are created equal, Meaney explained. By attentively watching mother rats and their pups during the first week of life, he and his research team also noticed that some mothers licked and groomed their newborns a lot, others less or not at all. The mothers that licked and groomed the most were the same ones who arched their bodies to accommodate the nursing pups.

As it happened, these more attentive dams ended up with pups that were better able to face the stresses of adult life. Solicitous nurturing during the first days and weeks of life meant fewer stress-related hormones circulating in the pups’ bloodstreams when they faced a scary event. They startled less easily. They were also more open to eating new foods. They were more adventurous in new terrain. They could navigate mazes and recognize objects better than pups of low-licking moms. And their enhanced memory and spatial skills were matched by synaptic changes in the hippocampus, an area of the brain specialized for memory. If the pups were female, their early experience
with responsive, attentive mothers seemed to make them more responsive mothers themselves.
⁴²

Rather than turning them into wimps, maternal TLC increased the pups’ resilience. What’s more, such responsive maternal care was transmitted to the next generation. When pups born of low-licking mothers were fostered by high-licking dams, they acted more like their adoptive mothers than their biological ones. Being on the receiving end of solicitous mothering in the first weeks of life transformed their responses to stress.

Like the descendants of the women who lived through the Dutch hunger winter, the offsprings’ DNA itself wasn’t changed by early experience. But the chemical coating surrounding their DNA was, and that altered layer determined how their genetic code would play out. According to Meaney’s research, subtle differences in maternal behavior could permanently change the way a baby’s genes are expressed. And that baby could pass on these environmentally tweaked traits to subsequent generations.

Though this research profoundly shifted the way many psychologists thought about child development, we’ve long known that nurturing-related brain changes are not limited to rodents. In the late 1950s, American research psychologist Harry Harlow separated rhesus monkeys from their mothers at birth and watched what happened when they were raised by their peers or with wire models he called surrogates. The surrogates were hollow metal forms that he had fitted with milk-filled baby bottles. They provided nourishment and a frame to cling to, but nothing else. Harlow soon discovered that without the affectionate give-and-take of early maternal contact, the monkeys couldn’t learn how to play or to interact in a normal way. They just sat there, engaging in repetitive, self-stimulating behaviors. As Deborah Blum writes in
Love at Goon Park
, instead of playing with other monkeys and trying new experiences on for size, the surrogate-raised infants clung to the bars of their cages for hours
and shrieked at passersby. “Others mauled themselves, biting their arms, ripping out fur.”
⁴³

More recently, studies by a former student of Harlow’s, Stephen Suomi, and his colleagues at the National Institute of Child Health, have shown that infant monkeys deprived of solicitous maternal care become impulsive and aggressive adults. Suomi and the team separated infant rhesus monkeys from their mothers and raised them with their peers; they had social contact but not motherly love. Nearly all of the monkeys who’d been separated from their mothers within the first six months of their lives exhibited weirdly exaggerated responses to stress as adults, including elevated levels of cortisol in their bloodstream and marked differences in the proteins that regulate neural cell growth and survival.
⁴⁴
When given the opportunity, these monkeys downed large quantities of alcohol—especially if they were male.
⁴⁵

Could a major disruption in face-to-face care be the catalyst that helps turn on the genes related to certain psychological disorders, such as attention and anxiety disorders, major depression, and alcoholism? If so, inheriting the genes for a disorder would mean you’d received the raw materials, but you’d need a double whammy of adversity to switch on the problem. Scientists called this the “two-hit” model. The first hit would be the loss of engaged parenting in infancy. The second hit would come much later, when these babies were older.

H
er name was Claudia Aristy and she may well have been headed for a life of inner-city poverty had she not found herself in Bellevue Hospital’s adolescent parenting group in New York. It was 1996; Aristy was just sixteen and she had recently arrived from the Dominican Republic. During a previous visit to New York she had fallen in love with a thirty-year-old man and become pregnant. “So I had come back to New York to live with my baby’s father,” Aristy told me as we chatted in Bellevue’s pediatric day clinic. “And my grandmother decided Bellevue was a safe place where I could get good medical care.”

A home-care worker who knew her way around the city, Claudia’s grandmother took the subway to the clinic with her granddaughter the first time. After that, Claudia was on her own. She admits now that she had a tough time. “Being in a different country and having to learn to navigate a different culture, a different language, and being far away from your family when you’re pregnant and you’re going through so many emotions—it’s really difficult,” she said. “And I was starting to wonder, what’s going to happen? Am I going to be a good parent? You want to show and prove to the world that even though you are pregnant and everybody considers it such a big mistake, that you’re going to be okay, you’re going to be a good mom.”

Now thirty-two, Claudia is employed as a bilingual parent educator by one of the hospital’s longstanding outreach programs that target New York’s low-income families. Claudia
had
faced difficulties. But, buttressed by the social support provided by Bellevue, she had made it past them; her son, Alejandro, was a thriving, guitar-playing teenager. Now her job is to connect with other parents to show them what it takes so that their kids will be able to make it too.

Banking on the deep trust most parents have in their kids’ doctors, in the late eighties a few pediatricians at Boston City Hospital asked themselves the following question: what would happen if pediatricians prescribed face-to-face interaction and a daily diet of reading to children with the same gravitas they applied to medical issues? The reasoning was that if some children lived in highly verbal, print-rich home environments while others did not, then promoting reading and giving out free books might help level the playing field a little. It would certainly do no harm. And it would be cheaper than previous early childhood stimulation programs.
¹
By incorporating books into vulnerable kids’ regular medical checkups there would be built-in continuity as the child grew. Besides, which doctor wouldn’t enjoy sharing the books they had read to their own children?

The group, which included pediatricians Robert Needlman, Barry Zuckerman, and Alan Mendelsohn, decided to test the idea empirically. They started by putting developmentally appropriate books into the hands of low-income parents at each child’s medical checkup, targeting clinics with a high number of vulnerable families. Along with encouraging parents to read to their children, the hope was that a growing collection of books at home might help narrow the gap between the five-year-olds who walked into kindergarten ready to learn to read, and the more than one-third who did not. It was a simple idea that took off. By the time I visited the program at Bellevue
on a balmy February day in 2012, there were twenty-eight thousand medical professionals, thousands of parent educators like Claudia Aristy, and innumerable volunteers working in more than five thousand pediatric clinics all over the United States. Together they had handed out 6.5 million new books to millions of preschoolers.