Figure 1.

Sub-transitions of the major transition from small- to large-scale human societies, with the major triggers for subsequent changes indicated, as well as crude estimates of the timing of these transitions. Solving the collective action problems inherent in large-scale agriculture may or may not have involved coercion depending on the society (e.g. over management of irrigation [5–7]). However, the surpluses provided by agriculture eventually led to hierarchal institutions that were prone to collapse and be reformed [8], culminating in the first states ca 4 kya.