In this study, the authors draw from intensity theory and combine previous research from the fields of behavioral ecology, economics, and social evolution to analyze drivers in the emergence and persistence of inequality across the world. They propose that environmental heterogeneity and circumscription (the difficulty of moving and establishing oneself in a new environment relative to remaining in the current one) play a significant role in the stratification of societies. Their results indicate that situations arise from various environmental conditions and levels of circumscription that may result in an individual giving up autonomy for material gain, thus favoring inequality.

In this study, the authors draw from intensity theory and combine previous research from the fields of behavioral ecology, economics, and social evolution to analyze drivers in the emergence and persistence of inequality across the world. They propose that environmental heterogeneity and circumscription (the difficulty of moving and establishing oneself in a new environment relative to remaining in the current one) play a significant role in the stratification of societies. Their results indicate that situations arise from various environmental conditions and levels of circumscription that may result in an individual giving up autonomy for material gain, thus favoring inequality.

In this study, the authors draw from intensity theory and combine previous research from the fields of behavioral ecology, economics, and social evolution to analyze drivers in the emergence and persistence of inequality across the world. They propose that environmental heterogeneity and circumscription (the difficulty of moving and establishing oneself in a new environment relative to remaining in the current one) play a significant role in the stratification of societies. Their results indicate that situations arise from various environmental conditions and levels of circumscription that may result in an individual giving up autonomy for material gain, thus favoring inequality.

In this study, the authors draw from intensity theory and combine previous research from the fields of behavioral ecology, economics, and social evolution to analyze drivers in the emergence and persistence of inequality across the world. They propose that environmental heterogeneity and circumscription (the difficulty of moving and establishing oneself in a new environment relative to remaining in the current one) play a significant role in the stratification of societies. Their results indicate that situations arise from various environmental conditions and levels of circumscription that may result in an individual giving up autonomy for material gain, thus favoring inequality.

In this study, the authors draw from intensity theory and combine previous research from the fields of behavioral ecology, economics, and social evolution to analyze drivers in the emergence and persistence of inequality across the world. They propose that environmental heterogeneity and circumscription (the difficulty of moving and establishing oneself in a new environment relative to remaining in the current one) play a significant role in the stratification of societies. Their results indicate that situations arise from various environmental conditions and levels of circumscription that may result in an individual giving up autonomy for material gain, thus favoring inequality.

In this study, the authors draw from intensity theory and combine previous research from the fields of behavioral ecology, economics, and social evolution to analyze drivers in the emergence and persistence of inequality across the world. They propose that environmental heterogeneity and circumscription (the difficulty of moving and establishing oneself in a new environment relative to remaining in the current one) play a significant role in the stratification of societies. Their results indicate that situations arise from various environmental conditions and levels of circumscription that may result in an individual giving up autonomy for material gain, thus favoring inequality.

In this study, the authors draw from intensity theory and combine previous research from the fields of behavioral ecology, economics, and social evolution to analyze drivers in the emergence and persistence of inequality across the world. They propose that environmental heterogeneity and circumscription (the difficulty of moving and establishing oneself in a new environment relative to remaining in the current one) play a significant role in the stratification of societies. Their results indicate that situations arise from various environmental conditions and levels of circumscription that may result in an individual giving up autonomy for material gain, thus favoring inequality.

In "The Urban Revolution" (1950), V. Gordan Childe hypothesized ten traits of civilization: urban centers, occupational specialization, monumental buildings, taxation by and/or tribute to elite, isolation of ruling group(s), writing, art, long-distance trade, social solidarity reinforced through common ideologies, and state formation. The author of this study analyzes these traits, and in particular, the presence of written language, with data from two different databases, one ethnographic and one archaeological. He finds that written language is highly correlated with the other traits of civilization as hypothesized by V. Gordan Childe.

In "The Urban Revolution" (1950), V. Gordan Childe hypothesized ten traits of civilization: urban centers, occupational specialization, monumental buildings, taxation by and/or tribute to elite, isolation of ruling group(s), writing, art, long-distance trade, social solidarity reinforced through common ideologies, and state formation. The author of this study analyzes these traits, and in particular, the presence of written language, with data from two different databases, one ethnographic and one archaeological. He finds that written language is highly correlated with the other traits of civilization as hypothesized by V. Gordan Childe.

The authors investigate the relationship between linguistic diversity and various environmental and spatial variables associated with biodiversity. Most of these variables predict linguistic diversity variably across different continents, and more so within Africa and extended Asia (Asia, the Pacific, and Australia) than within Europe and the Americas. This divide is theorized to be a result of differences in demography and impact of colonialism between the two global regions. However, two environmental factors, landscape roughness and density of river systems, are found to be significant predictors across all global regions. The authors suggest that, as in processes of speciation, rough terrain and watercourses both create physical barriers between which languages can develop in isolation while, in the case of river junctions, also providing transportation routes whereby hybrid languages can occasionally manifest.