For thousands of years, scholars have been theorizing about why human groups structure themselves the way they do, allowing more power and freedom to certain individuals and less to others. This article takes an evolutionist approach to that question, using a variety of mathematical models to predict changes in social organization throughout the evolutionary history of humanity and its ancestors, accounting for changes in brain size and global human populations. The authors validate their models using data from the ethnographic record. In general, they find that tendency towards hierarchy decreases with bigger brain size but increases with global population growth.

This article explores the relationship between language structure and social environment, positing that linguistic factors such as morphological complexity are associated with demographic/socio-historical factors such as number of speakers, geographic spread, and degree of language contact. Data support such an association. The authors further propose a Linguistic Niche Hypothesis suggesting that “the level of morphological specialization is a product of languages adapting to the learning constraints and the unique communicative needs of the speaker population” (7).

This article examines the evolution of games, particularly the way the complexity of games is affected by political organization, demographics, social differentiation, and religious differentiation.

The author builds upon previous research (Winkelman 1998) to further elucidate the cross-cultural predictors of institutionalized human sacrifice. The author considers a range of ecological factors and political variables, particularly geopolitical dynamics and intra- and inter-group relations. Other factors were explored, including social complexity and social structures. The author identifies the lack of an effective superordinate political authority as a main determinant in similar behaviors contemporarily (e.g. suicide bombers, beheadings, public brutality in civil war).

This article uses a Darwinian approach, predicting that hierarchies persist and increase in social evolution because they increase fitness for individuals at higher levels within the hierarchy who choose to further social assymetry and benefit their fitness at the expense of the greater group. Polygyny is used as the indicator of fitness. Correlations tested support the hypothesis.

This article reviews literature on social evolution, urbanization, and their interrelationships before empirically examining the relationship between settlement size and organizational complexity. An index of social development composed of three indicators is introduced, critiqued, and compared to other classification systems.

It is suggested that the degree of political complexity is more strongly related to degree of social differentiation than to size and concentration of population.

This study examines socio-economic predictors of political complexity. Findings suggest that class stratification is the most significant predictor of political complexity.

This chapter examines the presence of oaths and autonomic ordeals in relation to various socioeconomic variables. Several hypotheses are presented, all are supported.

This study investigates the relationship between societal complexity and familial complexity. Results suggest that the relationship is somewhat curvilinear; that is, in simpler societies more societal complexity is associated with a larger familial system, but the most developed societies have smaller familial systems. The demographic, economic, and politcal correlates of maximum family size are discussed.