There is a paradox at the heart of much of the new research on early adversity and child development: While the problems that accompany poverty may be best understood on the molecular level, the solutions are not. These days it often feels as though you need a Ph.D. in neurochemistry to understand the full scope of what’s going on in the lives of disadvantaged children. And yet the intricacies of that science—the precise mechanisms through which adrenal glands release glucocorticoids and immune cells send out cytokines—don’t tell us much about how best to help children in trouble. Perhaps someday there will be neurochemical cures for these neurochemical imbalances—a shot or a pill that will magically counter the effects of childhood adversity. But for now, the best tool we have to correct or compensate for those effects is an unwieldy one: the environment in which children spend their days.
When we hear the word environment, we often think first of a child’s physical environment. And adverse physical surroundings do play a role in children’s development, especially when they are literally toxic, as when children are exposed to lead in their drinking water or carbon monoxide in the air they breathe. But one of the most important findings of this new cohort of researchers is that for most children, the environmental factors that matter most have less to do with the buildings they live in than with the relationships they experience—the way the adults in their lives interact with them, especially in times of stress.
The first and most essential environment where children develop their emotional and psychological and cognitive capacities is the home—and, more specifically, the family. Beginning in infancy, children rely on responses from their parents to make sense of the world. Researchers at the Center on the Developing Child at Harvard University have labeled these “serve and return” interactions. Infants make a sound or look at an object—that’s the serve—and parents return the serve by sharing the child’s attention and responding to his babbles and cries with gestures, facial expressions, and speech: “Yes, that’s your doggy!” “Do you see the fan?” “Oh dear, are you sad?” These rudimentary interactions between parents and babies, which can often feel to parents nonsensical and repetitive, are for the infants full of valuable information about what the world is going to be like. More than any other experiences infants have, they trigger the development and strengthening of neural connections in the brain between the regions that control emotion, cognition, language, and memory.
A second crucial role parents play early on is as external regulators of their children’s stress, in both good ways and bad. Research has shown that when parents behave harshly or unpredictably—especially at moments when their children are upset—the children are less likely over time to develop the ability to manage strong emotions and more likely to respond ineffectively to stressful situations. By contrast, parents who are able to help their children handle stressful moments and calm themselves down after a tantrum or a scare often have a profoundly positive effect on the children’s long-term ability to manage stress. Infancy and early childhood are naturally full of crying jags and meltdowns, and each one is, for the child, a learning opportunity (even if that’s hard to believe, in the moment, for the child’s parents). When a child’s caregivers respond to her jangled emotions in a sensitive and measured way, she is more likely to learn that she herself has the capacity to manage and cope with her feelings, even intense and unpleasant ones. That understanding, which is not primarily an intellectual understanding but instead is etched deep into the child’s psyche, will prove immensely valuable when the next stressful situation comes along—or even in the face of a crisis years in the future.
Neuroscientists have over the past decade uncovered evidence, both in rodent and human studies, that parental caregiving, especially in moments of stress, affects children’s development not only on the level of hormones and brain chemicals, but even more deeply, on the level of gene expression. Researchers at McGill University have shown that specific parenting behaviors by mother rats change the way certain chemicals are affixed to certain sequences on a baby rat’s DNA, a process known as methylation. Warm and responsive parenting when a baby rat is stressed-out—in particular, a soothing maternal behavior called licking and grooming—creates methylation effects on the precise segment of the baby rat’s DNA that controls the way its hippocampus will process stress hormones in adulthood. And there are strong indications (though concrete evidence is still emerging) that the same methylation effects take place in human babies in response to corresponding human parenting behaviors. The McGill research validates what many parents (and former children, looking back on childhood) intuitively feel: Even small moments of parental attention can help nurture children’s development on a very deep level—burrowing all the way down, it turns out, to our essential genetic code.