In addition to different dynamics in different bundles of trajectories (competition and prestige or wealth differentiation are strongly developed in some, cooperation in others), a few commonalities crosscut multiple bundles. Complexification almost always occurs in conditions of demographic growth, although the population levels vary enormously. Residential density regularly plays an important role in shaping interaction patterns related to productive differentiation, integration of local economies, and wealth accumulation on the one hand or attenuated interaction, and ritual and prestige differentiation, on the other. Such forces operate in the same way in all parts of the world, overriding supposedly typical cultural patterns.

Challenging typological definitions and unilineal evolution, this chapter advocates for a comparative methodology centered on understanding variation in trajectories of complexification. It underscores the limitations of “dichotomania” and the need for richer conceptual and linguistic tools to characterize societal variation.

The ways in which human interaction was restructured during complexification in fifty-seven natural experiments from around the world, is characterized in twenty-one variables in the domains of interaction, demography, and political economy. Examination of the data in this way reveals an enormous range of variation among early complex societies on all counts.

A comparison of trajectories (i.e., of how things change through time in complexification) is pursued graphically by aligning trajectories in time according to their points of initial regional integration and of maximal differentiation. Some of these patterns of change “rhyme” in time and signal bundles of trajectories in which similar changes can be seen as responses to similar forces.

Rigorous collection, reporting, and analysis of household artifact assemblage data in future research would make it possible to characterize differentiation of all kinds with greater confidence. The lack of regional-scale settlement research in some regions leaves demographic estimates lacking good support. The richness of ethnographic information for some places has undermined the archaeological research needed to say how organization developed before the “ethnographic present.”

Primary archaeological knowledge is produced through intensive regional specialization – the antithesis of broad comparative analysis, which demands critical and consistent expert evaluation of information across multiple areas. The availability and quality of data from different regions are spotty, requiring new and more robust analytical approaches for complete reanalysis of primary data for comparative purposes.

Distinguishing between wealth, prestige, productive, and ritual differentiation proves especially enlightening in ferreting out the dynamics underlying different bundles of trajectories in which social complexity emerges in different ways and takes different forms. Ideas previously posed as contradictory accounts of the universal origin of social complexity are seen to be complementary accounts of different bundles.

As economies become more complicated with increasing interdependence tied to exchange and specialization, inequality appears as an outcome of dispersed versus concentrated flows and accumulations of value that affect differences in well-being, power, and institutional formations. We look at the complicated institutional arrangements that favor or limit inequality, perhaps the most important of which is the development of institutional property and how it allowed control over production and distribution. The theoretical and empirical breadth of inequality is vast. For this comparative effort, we formulate an approach that can analyze inequalities in wealth and property from widely different social formations, including the segmentary societies of Pare, Tanzania, and Zuni in the American Southwest, chiefdoms in the Scandinavian Bronze Age (BA), and advanced states and empires such as Rome and the Inca. Within this broad spectrum, differences in the control of wealth, prestige, ranking and/or ascribed rank are intertwined but not necessarily overlapping. Our approach focusses on how access to and control over material wealth is distributed in our sample.