For several years Jesse Ausubel and Cesare Marchetti have been pondering the growth of human empires through the lens of biological models. The International Journal of Anthropology has now published their paper, Quantitative Dynamics of Human Empires. The paper reports that the driving forces of empire, leading to expansion and saturation at 14 days of travel from the capital, can be reduced to testosterone and progesterone.
The paper has been published in black-and-white. Thanks to the journal editors for accepting a paper from scholars outside the discipline of anthropology. We also have a posted an enriched powerpoint-style version of the text and figures with the many maps and images in color. We recommend the color version.
Quantitative modeling of social systems shows a large component of automatic drives in the behaviour of individual humans and human society. Studies of the formation and breakdown of twenty diverse empires operating over almost three thousand years describe these processes with utmost clarity and paradigmatic simplicity. Taking territorial expansion as the basic parameter, we show that it can be represented in time by a single logistic equation in spite of the complicated sequences of events usually reported by historians. The driving forces of empire, leading to expansion and saturation at 14 days of travel from the capital, can be reduced to testosterone and progesterone.