A long-standing debate in the field of cultural evolution has revolved around the question of how and why human societies become more hierarchical. Some theorize that material changes to a society’s resources or subsistence strategies lead it to become more hierarchical; others believe that hierarchy is the cause rather than the result of these changes. Many see the answer as being somewhere on the spectrum between these two extremes. In order to test these theories, a group of researchers from the Max Planck Institute for the Science of Human History and the University of Auckland examined 155 Austronesian societies, the results of which are published in PNAS.