  Numerous researchers from various disciplines have explored commonalities and
divergences in the evolution of complex social formations. Here, we explore
whether there is a 'characteristic' time-course for the evolution of social
complexity in a handful of different geographic areas. Data from the Seshat:
Global History Databank is shifted so that the overlapping time series can be
fitted to a single logistic regression model for all 23 geographic areas under
consideration. The resulting regression shows convincing out-of-sample
predictions and its period of extensive growth in social complexity can be
identified via bootstrapping as a time interval of roughly 2500 years. To
analyse the endogenous growth of social complexity, each time series is
restricted to a central time interval without major disruptions in cultural or
institutional continuity and both approaches result in a similar logistic
regression curve. Our results suggest that these different areas have indeed
experienced a similar course in the their evolution of social complexity, but
that this is a lengthy process involving both internal developments and
external influences.
