Under the title “Is This the Silver Bullet?”, the winter 2008 issue of Stanford Social Innovation Review (SSIR) cites recent research showing that narrowing the gap between rich and poor appears to alleviate a wide range of social ills:

What do teenage births, early deaths, homicide, mental illness, underperforming students, packed prisons, and drug abuse have in common? All of them thrive in countries with large gaps between the rich and the poor, report two researchers in the November 2007 Social Science & Medicine.

What is the mechanism behind this? According to SSIR, “inequality exacts its costs by causing people to feel less socially secure and more physiologically stressed.” One result of a wide gap between rich and poor is decreased social mobility, and this can cause persons in less egalitarian countries to feel “deprived,” and can even lead to a shortened life span, compared to poorer but more egalitarian countries. Additionally, a large gap between rich and poor has significant detrimental effects on persons of all income levels — inequality has “a pollution effect” and affects everyone’s health — thus, it is actually advantageous to rich persons to reduce the income gap, to improve their own health and quality of life.

You probably won’t be surprised to know that the United States has one of the worst gaps between rich and poor of any industrialized nation. The policy implications of this study for the United States are significant. Want to improve children’s test scores? The conservatives tell us we must have rigorous testing, the liberals say we must have smaller class sizes, but the social epidemiologists tell us that research shows we should reduce income disparity. Want to reduce crime? The conservatives want fewer restrictions on gun ownership, the liberals want to fund more social programs, but the social epidemiologists tell us that research shows we should reduce income disparity.