According to the classic academic narrative of political evolution, post-ice age complexity — defined as increasing levels of social hierarchy — evolved slowly but surely, with mechanical predictability. First came egalitarian bands of closely-related people; then came larger but still-egalitarian tribes, with only informal leadership; these clustered into chiefdoms, with hereditary leaders; chiefdoms united into states, with bureaucracies and administrative offices.
To some scholars, however, this narrative is deterministic. They say that political evolution doesn’t proceed neatly from lower to higher complexity, but proceeds in bursts. To them, tribes, chiefdoms and states all represent distinct evolutionary trajectories rather than stages of a single progression. The critics also say that the tendency of societies to move from higher to lower complexity has been underestimated.
Here is the article's abstract:
There is disagreement about whether human political evolution has proceeded through a sequence of incremental increases in complexity, or whether larger, non-sequential increases have occurred. The extent to which societies have decreased in complexity is also unclear. These debates have continued largely in the absence of rigorous, quantitative tests. We evaluated six competing models of political evolution in Austronesian-speaking societies using phylogenetic methods. Here we show that in the best-fitting model political complexity rises and falls in a sequence of small steps. This is closely followed by another model in which increases are sequential but decreases can be either sequential or in bigger drops. The results indicate that large, non-sequential jumps in political complexity have not occurred during the evolutionary history of these societies. This suggests that, despite the numerous contingent pathways of human history, there are regularities in cultural evolution that can be detected using computational phylogenetic methods.
In short, the article argues (as shown in the following diagram) that political complexity evolves slowly through a series of stages (e.g., from simple chiefdom to complex chiefdom to state), but can fall apart much more rapidly and dramatically (e.g., in addition to reversing the process described above, a collapsing society could go directly from state to simple chiefdom).
While this is more speculation than evidence based conclusion, translating these findings into a panarchy framework highlights some interesting possibilities. Specifically, it seems that some of the transitions (e.g., from simple to complex chiefdom) would most likely be the product of adaptive cycle processes. Others, however (e.g., from complex chiefdom to state), seem intuitively to involve the emergence of processes operating at a larger scale (similar to the problem of going from nation-state to global governance). In other words, to involve the emergence of a new and separate adaptive cycle that operates at a larger scale. If this is the case, this would also make sense of the asymmetric nature of the process whereby development occurs in a path (with each level in the controlling panarchy necessary for the emergence of the next) but collapse can be more dramatic (as processes of cross-scale interaction cascade down through the panarchical levels).