By Maia Szalavitz
Inequality is at an all-time high in America. Since the 2008 crash, recent IRS figures show, the wealth of the top 1 percent grew 31 percent while the rest of American incomes grew by less than 1 percent. But although it might appear that income disparities affect only the poor and have primarily an economic impact, dozens of studies now link extreme inequality with poor health and shorter lives, across the entire socioeconomic spectrum.
Overall, the United States has among the largest social and economic inequalities of any rich country. Japan and the Scandinavian countries have the smallest. The more equal countries also have the longest life expectancies — and the richest American men only have the life expectancy of an average Japanese man, which is 4.5 years longer than the U.S. average, according to Sir Michael Marmot, a leading researcher on inequality and professor of epidemiology at University College London. He notes that residents of affluent suburban Maryland live, on average, 17 years longer than people in inner city Washington, D.C.
Marmot's own research focuses on the UK, where a national healthcare system provides all socioeconomic classes with quality care. He has compared low- and high- ranking British civil servants over the course of their lives on a variety of health measures, ranging from cancer to obesity to alcohol addiction. For virtually all conditions except breast and prostate cancer (it is not clear why these are exceptions), Marmot found that those at the bottom are at dramatically greater risk, with overall mortality up to three times higher, depending on the specific condition. Increased levels of unhealthy behavior among the less-affluent — like smoking — did not account for all of the differences. Also, even the lowest-ranked civil servants in Marmot's research were employed, meaning that those on bottom rungs weren't impoverished, simply less well-off.
The reason for the differences, say Marmot, Stanford neuroscientist Robert Sapolsky, Rockefeller University's Bruce McEwen and a growing number of their peers, is found instead in the stress system, which in primates seems fine-tuned to rank and hierarchy — not absolute poverty, but relative social position.
"For the poor, more inequality means more anger at what they don't have and more cognitive load from the worry about how to keep up," Sapolsky says. "For the wealthy, it's more fear about the menace of the have-nots and more effort put into walling themselves off from them. For everyone, there's less social support — by definition, the more widely-spread and unequal a hierarchy, the fewer peers one has, and true social support requires the symmetry of peers."
In the baboons Sapolsky has studied, low status is linked to high levels of the stress hormone cortisol, which can compromise the immune system. Low-ranked baboons, like lower-status humans, have a weakened response to infectious diseases and an increased risk for cardiovascular disease and most cancers. In nonhuman primates, however, those illnesses occur without being able to smoke, drink, binge on junk food or take other drugs in an attempt to manage the stress.
Rank-related social stress, like stress from bullying, is also more damaging to health than other types of stress. While "executive stress" linked to having control over others was once seen as a cause of heart attacks, it's actually the guy being humiliated and berated by the boss, or the kid being taunted by his classmates, who is at greatest risk.
Ongoing social rejection can be toxic to the brain. Studies show that for our ancestors, being cast out of the tribe was a literal death sentence, while other types of stressors, like facing predators, were typically more survivable. Current research on childhood bullying shows an impact years later in increased rates of depression, reduced employment and even higher crime.
But baboon research also makes the case that health effects of status stress are not inevitable. Not all baboon troupes are alike. Similar to human cultural variations, there are variances in leadership styles, in stability of the hierarchy and in how much punishment the ones at the top dish out. In one group studied by Sapolsky, when an epidemic killed off the toughest top-ranked males, health and stress hormone differences related to rank disappeared, as the new leadership didn't do much bullying and restricting of access to food and females.
Inequality is unhealthy, it seems — and better health for all results from reducing it in social species. While it's unrealistic and dangerous to try to completely eliminate economic disparities — as past attempts have clearly shown — Scandinavian countries demonstrate that reducing it can be done while maintaining a vibrant and productive economy. Because status stress changes our hormones and immune systems, greater fairness benefits everyone in ways that go far beyond basic economics.
(Maia Szalavitz is a Reuters columnist. Opinions are her own.)