Rome was not built in one day: Underlying biological and cognitive factors responsible for the emergence of agriculture and ultrasociality.

Agriculture represented a major transition in human evolution, but the appearance of ultrasociality must have included previous steps. We argue that ultrasociality would not have suddenly emerged with agriculture, but rather developed from pre-existing cognitive and social mechanisms. Discussions must include necessary depth about the historical origins of human ultrasociality, and agriculture's aftereffects on large-scale social organization.

Cooperation and emergence: the missing elements of the Darwin machine.

The authors present a compelling argument for a science of intentional change by unifying evolutionary psychology (EP) with the standard social science model; however, since its inception, traditional EP models have not held up well to empirical scrutiny. The authors address the importance of cooperation in individuals and social systems, but the Darwin machine they propose does not adequately stress fundamental aspects of evolutionary processes.

The evolution and development of human social systems requires more than parasite-stress avoidance explanation.

Fincher & Thornhill (F&T) present a model of in-group assortative sociality resulting from differing levels of parasite-stress in differing geographical locations in the United States and the world. Their model, while compelling, overlooks some important issues, such as mutualistic associations with parasites that are beneficial to humans and how some religious practices increase parasite risk.