Can phylogenetic methods from evolutionary biology inform us about how societies evolve?

This coming lab-meeting (Wednesday 27 October), I was thinking that we should discuss if and how methods from evolutionary biology can elucidate problems studied by political scientists: the rise and fall of societies. There is an interesting article published in Nature, where the authors used phylogenetic methods to investigate if societies evolved towards more complexity (or not). The study was performed on a set of societies in South-East Asia and in the Pacific.  

Evolutionary biologist and community ecologist Jared Diamond has an interesting perspective about the study. Read both the comment by Diamond and the original article so that we can have an interesting discussion on Wednesday. Time and place as usual: "Darwin" at 10.15. Below is the abstract and title of the original paper:

Rise and fall of political complexity in island South-East Asia and the Pacific  

Thomas E. Currie,Simon J. Greenhill, Russell D. Gray, Toshikazu Hasegawa & Ruth Mace 

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.