Quantitative historical analysis uncovers a single dimension of complexity that structures global variation in human social organization.

Do human societies from around the world exhibit similarities in the way that they are structured, and show commonalities in the ways that they have evolved? These are long-standing questions that have proven difficult to answer. To test between competing hypotheses, we constructed a massive repository of historical and archaeological information known as "Seshat: Global History Databank." We systematically coded data on 414 societies from 30 regions around the world spanning the last 10,000 years. We were able to capture information on 51 variables reflecting nine characteristics of human societies, such as social scale, economy, features of governance, and information systems. Our analyses revealed that these different characteristics show strong relationships with each other and that a single principal component captures around three-quarters of the observed variation. Furthermore, we found that different characteristics of social complexity are highly predictable across different world regions. These results suggest that key aspects of social organization are functionally related and do indeed coevolve in predictable ways. Our findings highlight the power of the sciences and humanities working together to rigorously test hypotheses about general rules that may have shaped human history.

Progress, decline, and the public uptake of climate science.

Previous research has sought to explain public perception of climate change science in terms of individuals' "prior commitment" to such ideological stances as just-world belief, system justification, and liberalism/conservatism. One type of prior commitment that has received little formal attention in the literature is narratives of the moral trajectory of society. A theory of climate science uptake based on beliefs in societal progress or decline is more easily portable to non-Western settings; in a case study of global warming attitudes in the Marshall Islands, trajectory narratives indeed account for public belief, concern, blame, and response more aptly than existing theories, and accord well with qualitative analysis of Marshallese climate change discourse. In Western settings, progress/decline narratives may explain much of the variation in climate change attitudes previously accounted for by other ideological variables, promising a more penetrating explanation for the divergence of climate change attitudes within and between societies.