I understand that during the Early Dynastic period there was the phenomenon of "hyperurbanism" in which, due to the usual cocktail of reasons, rural settlements were abandoned in favor of the rapidly swelling urban areas. I heard one time a jaw dropping 50% urbanization rate, which flies in the face of much of my experience with ancient demographics. But is this population shift "real" or does it only seem to be because of the central place that urban tel sites have in archaeological research?
It is 'real' in the sense that there is extensive data from archaeological surveys that study the settlement development over a longer time - in terms of settlement distribution, but also in terms of settlement size. Adams 'Heartland of Cities' has the data and the visualisations and is a very interesting read!
The development seems more pronounced around the city of Uruk than with other urban centres, particularly in the North, but it seems to be a general trend.