IHDP's Deborah Rogers writes about inequality in PLoS ONE
Population Instability and Higher Migration Rates May Have Caused Stratified Societies to Spread Across the Globe
Why do most cultures have a class structure – rich, poor and middle class – instead of being egalitarian, with equal access to resources for everyone? According to a group of Stanford University researchers, including IHDP’s Deborah S. Rogers, it is the very inequality of that class structure that may have caused the spread of such societies and the displacement of more egalitarian cultures during the development of human civilization.Rogers and the others used a computer simulation to compare demographic stability and rates of migration for both egalitarian and unequal societies. They found that class differences in birth and death rates due to unequal access to resources has a destabilizing effect on the population, driving migration and the expansion of stratified societies. The paper, published online Wednesday, September 21 by the Public Library of Science in the journal PLoS ONE, is the first to demonstrate a specific mechanism by which stratified societies may have taken over most of the world.
Rogers and her colleagues determined that in egalitarian societies, where resources are shared equally among the entire population, the population is able to stabilize and thus has less incentive to migrate in search of resources. When resources were scarce, stratified societies were not only migrated more frequently, but were also better able to survive temporary shortages because the bulk of the deprivation was absorbed by the lower classes, leaving the ruling class – and the overall social structure – intact. Both factors caused stratified societies to migrate in search of additional resources more rapidly than egalitarian societies, helping to spread the culture of stratification.
“The fact that unequal societies vastly outnumber egalitarian societies today may not be due to the adoption by societies of an acquisitive and social-climbing ethic which leads to stratification, as originally thought by many researchers,” said cultural evolution specialist Deborah Rogers, lead author of the study. “Instead, it appears that the stratified societies simply spread and took over, crowding out the more egalitarian populations.”
“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.”
The authors of the report include Rogers, then a PhD student at Stanford and now a researcher at the International Human Dimensions Programme (IHDP), United Nations University, in Bonn, Germany; Marcus W. Feldman, director of the Morrison Institute for Population and Resource Studies at Stanford; and Omkar Deshpande, former PhD student in the Computer Science Department at Stanford. Funding for the study was provided by the National Science Foundation, the Morrison Institute for Population and Resource Studies, Stanford University, and the National Institutes of Health.
The article may be read at the PLoS ONE website, which is an on-line, freely-accessible open-access science journal: