Nobility and Stupidity: Modeling the Evolution of Class Endogamy
  Class endogamy is a phenomenon in which nobles only marry other nobles and commoners only marry other commoners. The origin of class endogamy, and of social stratification in general, is a major open question in archaeology. This paper implements a verbal model proposed by Marcus and Flannery as a class of agent-based computer models by generalizing and simplifying a mathematical model of marriage markets developed by Burdett and Coles. One force that can produce class endogamy occurs if agents are only willing to marry suitors having status no less than some fixed value below the status of their highest-status suitor, which they can learn. Another such force results if children inherit the average of their parents' statuses. In contrast, status achieved over an agent's lifetime can be viewed as noise, analogous to mutation in biological evolution. I propose that class endogamy may have resulted from the interaction of forces such as these, along with other factors such as ideology. Simulation results are presented, and potential areas for future research are sketched out. The validity of these models for any particular culture depends, of course, on whether these forces were actually operating in that society. 
Theodore C. Belding (University of Michigan Center for the Study of   Complex Systems)