High Income Inequality Helped Early Societies Spread, Study Finds

As political rhetoric surrounding "class warfare" heats up, a new study indicates that class stratification may help a society spread.

The unequal access to resources that comes with class stratification ultimately pushed societies to migrate, displacing more egalitarian cultures, according to a study from Stanford University. The study’s findings would indicate the U.S. itself has some expanding left to do; the total net worth of the bottom 60 percent of U.S. households is less than that of Forbes 400 richest Americans.

"The fact that unequal societies today vastly outnumber egalitarian societies may not be due to the replacement of the ethic of equality by a more selfish ethic, as originally thought by many researchers," said Deborah Rogers, the lead author of the study. "Instead, it appears that the stratified societies simply spread and took over, crowding out the egalitarian populations."

But even if stratification helped societies spread during the early era of civilization as the study suggests, rising income inequality could now be hindering economic growth, according to an International Monetary Fund study released earlier this month. If income inequality decreased by 10 percent, the duration of an expected period of economic growth would grow by 50 percent, according to the paper.

Americans may support a narrowing in the gap between classes, according to a recent poll by Daily Kos. The poll found that nearly three-quarters of Americans favor taxing households making more than $1 million at higher rate than middle class households. But when President Barack Obama proposed a rule along those lines earlier this month, he was met with accusations that he was stoking "class warfare."

And as the top 1 percent of America's earners control 40 percent of the wealth, according to Vanity Fair, the ranks of the American poor swelled to its highest level since the Census Bureau started keeping track in the 1950s.

A society's poor absorbs resource instability allowing the ruling class and the overall social structure to stay "in tact," according to the study. The stability allowed them to spread and outmaneuver more egalitarian societies, the study found.

"This is not just an academic exercise," Rogers said. "Inequalities in socioeconomic status are increasing sharply around the world. Understanding the causes and consequences of inequality and how to reduce it is one of the central challenges of our time."