Free The Best American Science and Nature Writing 2014 by Deborah Blum

and the gene networks and gene-expression cascades that they set off, “are surprisingly consistent—from monkeys to people, from five-year-old kids to adults, from Vancouver teenagers to sixty-year-olds living in Chicago.”
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    Cole’s work carries all kinds of implications—some weighty and practical, some heady and philosophical. It may, for instance, help explain the health problems that so often haunt the poor. Poverty savages the body. Hundreds of studies over the past few decades have tied low income to higher rates of asthma, flu, heart attacks, cancer, and everything in between. Poverty itself starts to look like a disease. Yet an empty wallet can’t make you sick. And we all know people who escape poverty’s dangers. So what is it about a life of poverty that makes us ill?
    Cole asked essentially this question in a 2008 study he conducted with Gregory Miller and Edith Chen, another social psychologist then at the University of British Columbia. The paper appeared in an odd forum:
Thorax
, a journal about medical problems in the chest. The researchers gathered and ran gene-expression profiles on thirty-one kids, ranging from nine to eighteen years old, who had asthma; sixteen were poor, fifteen well-off. As Cole expected, the group of well-off kids showed a healthy immune response, with elevated activity among genes that control pulmonary inflammation. The poorer kids showed busier inflammatory genes, sluggishness in the gene networks that control inflammation, and—in their health histories—more asthma attacks and other health problems. Poverty seemed to be mucking up their immune systems.
    Cole, Chen, and Miller, however, suspected something else was at work—something that often came with poverty but was not the same thing. So along with drawing the kids’ blood and gathering their socioeconomic information, they showed them films of ambiguous or awkward social situations, then asked them how threatening they found them.
    The poorer kids perceived more threat; the well-off perceived less. This difference in what psychologists call “cognitive framing” surprised no one. Many prior studies had shown that poverty and poor neighborhoods, understandably, tend to make people more sensitive to threats in ambiguous social situations. Chen in particular had spent years studying this sort of effect.
    But in this study, Chen, Cole, and Miller wanted to see if they could tease apart the effect of cognitive framing from the effects of income disparity. It turned out they could, because some of the kids in each income group broke type. A few of the poor kids saw very little menace in the ambiguous situations, and a few well-off kids saw a lot. When the researchers separated those perceptions from the socioeconomic scores and laid them over the gene-expression scores, they found that it was really the kids’ framing, not their income levels, that accounted for most of the difference in gene expression. To put it another way: when the researchers controlled for variations in threat perception, poverty’s influence almost vanished. The main thing driving screwy immune responses appeared to be not poverty, but whether the child saw the social world as scary.
    But where did
that
come from? Did the kids see the world as frightening because they had been taught to, or because they felt alone in facing it? The study design couldn’t answer that. But Cole believes isolation plays a key role. This notion gets startling support from a 2004 study of fifty-seven school-age children who were so badly abused that state social workers had removed them from their homes. The study, often just called “the Kaufman study,” after its author, the Yale psychiatrist Joan Kaufman, challenges a number of assumptions about what shapes responses to trauma or stress.
    The Kaufman study at first looks like a classic investigation into the so-called depression-risk gene—the