For the past several years, Miller and colleagues have studied the relationship between stress and physical health, and how self-control translates one into the other. For people who manage unlikely feats of upward mobility, how does that affect their bodies? On Monday the research team released findings that build out the picture of just how detrimental that rise can be. In Proceedings of the National Academy of Sciences, Miller and Tianyi Yu, Edith Chen, and Gene Brody build on their body of existing research showing that self-control among disadvantaged youth is associated with poorer physical health—higher blood pressures, more body fat, and higher levels of the stress hormone cortisol—compared to peers who are more impetuous (and, then, less upwardly mobile).

“We're talking about kids where the family is likely to be on multiple forms of government assistance, often single-parent caregivers with a high-school diploma or less,” Miller explained to me. “Those kids—who come from really, really challenging backgrounds but nonetheless do well in terms of psychosocial outcomes—by their early 20s have cells that look quite aged relative to their chronological age.”

The effect is related to the idea that chronic stress breaks down every bodily process and induces or at least catalyzes unknowably many diseases. The current case, a familiar one, opens with 496 black teenagers in rural Georgia, most from working-poor families. They are kids who begin with the panoply of disadvantages, related to race, geography, class—kids who, demographically, don’t do as well by traditional academic standards as others across the country, have more problems with mental and physical health, and have more contact with the juvenile justice system.

But there were outliers in that population, a subset of kids who despite the “odds being stacked against them,” as the researchers put it, excelled in school, exemplified mental health, didn't engage in criminal behavior or substance abuse, et cetera. “There's this group of kids that everybody is really excited about,” Miller said. “They beat the odds, and that's absolutely fantastic.”

As a psychologist, Miller brings an interest in the mindset that may have facilitated that success, and at what cost it was enacted. Though none of that excitement is meant to detract from the basic point that these odds ought ideally not to exist. Instead playing fields are so far from level that they make for effective experimental grounds, a study in psychosocial mediators of health requiring no laboratory-induced circumstances.

Meanwhile, the disadvantaged people who are not in the outlier super-conscientious group don't end up in those higher-pressure “successful” situations, and their bodies don't suffer for it. They are apparently spared the physical consequences of upward mobility. “What we're finding,” said Miller, “is that there seems to be a cost to self-control and/or to the successes that it enables.”