The especially early emergence of Neolithic walled towns in the Jianghan Plain is widely used as an indicator of social complexity. In recent decades, research on walled towns has focused on their role in the origin of Chinese civilization and in the formation of early states in China. Several models have been suggested to explain the emergence of walled towns: inter-regional conflicts between the Central Plain and the Jianghan Plain, intra-regional conflicts among walled towns in the Jianghan Plain, and control of flooding in the Neolithic period. The trajectories of developing social complexity of these earliest walled towns and the relationships that existed among them have not previously been systematically investigated from the perspective of demographic distributions. The full-coverage systematic regional survey presented here included two of the earliest walled towns in the Jianghan Plain: Taojiahu and Xiaocheng. It was designed to illuminate their social trajectories and by extension those of their counterparts elsewhere in the Jianghan Plain and areas adjacent to it.

The regional survey revealed spatial and temporal variations in the settlement patterns of an area of 58 km2 from 3900 BCE to 600 CE. Population distribution patterns were documented for each period in this time span to investigate the dynamic forces behind social and settlement changes. Different approaches to understanding the emergence of early walled towns were evaluated through the analysis of population distribution and its relationships to environmental variables.

The conclusions of the research include the following. First, the emergence of the Taojiahu and Xiaocheng walled towns was a process of the in situ population increase from initial small communities rather than pulling together people spread throughout the landscape in different communities. Second, throughout their histories, Taojiahu and Xiaocheng contained the vast majority of the population of their territories; there was little or no hinterland population or settlement hierarchy around them. Third, economic activities and the development of economic interdependence involving both subsistence and non-subsistence products were of particular importance at Taojiahu and Xiaocheng. Fourth, Xiaocheng might have served as an economic outpost of Taojiahu focused on the production of rice and other goods.