New findings provide quantitative criteria for classifying social organizations in human history, together with potential explanatory variables that can be empirically measured for anthropology, history and archaeology, according to a study published September 3, 2024 in the open-access journal PLOS Complex Systems by Kenji Itao and Kunihiko Kaneko from the University of Tokyo, Japan and Copenhagen University, Denmark (Kaneko) and the RIKEN Center for Brain Science, Japan (Itao).