COVENTRY, ENGLAND—According to a statement released by the University of Warwick, Joram Mayshar of the Hebrew University of Jerusalem, Omer Moav of the University of Warwick and Reichman University, and Luigi Pascali of Pompeu Fabra University and the Barcelona School of Economics claim that the production of cereal crops alone fueled the development of hierarchical societies. Unlike root crops, which can be kept in the ground, cereal crops must be harvested and stored, making them easier to access and tax, the researchers explained. It had been previously thought the growth of early hierarchies was driven by the availability of fertile land, but the study, which examined the level of hierarchical complexity in a society, the geographic distribution of wild relatives of domesticated plants, and land suitability for various crops, suggests that the most productive lands, where roots and tubers were grown in addition to cereals, did not experience the same political development as societies that relied solely on the growth of cereal crops, Pascali explained. “When it became possible to appropriate crops, a taxing elite emerged, and this led to the state,” Mayshar concluded. To read more about the role of taxation in the rise of empires, go to "Ancient Tax Time."