Craniofacial Feminization, Social Tolerance, and the Origins of Behavioral Modernity

Bibliographic Collection: 
Publication Type: Journal Article
Authors: Cieri, R.; Churchill, S.; Franciscus, R.; Tan, J.; Hare, B.
Year of Publication: 2014
Journal: Current Anthropology
Volume: 55
Start Page: 419
Issue: 4
Pagination: 419-443
Date Published: 08/2014
Publication Language: eng

The past 200,000 years of human cultural evolution have witnessed the persistent establishment of behaviors involving innovation, planning depth, and abstract and symbolic thought, or what has been called “behavioral modernity.” Demographic models based on increased human population density from the late Pleistocene onward have been increasingly invoked to understand the emergence of behavioral modernity. However, high levels of social tolerance, as seen among living humans, are a necessary prerequisite to life at higher population densities and to the kinds of cooperative cultural behaviors essential to these demographic models. Here we provide data on craniofacial feminization (reduction in average brow ridge projection and shortening of the upper facial skeleton) in Homo sapiens from the Middle Pleistocene to recent times. We argue that temporal changes in human craniofacial morphology reflect reductions in average androgen reactivity (lower levels of adult circulating testosterone or reduced androgen receptor densities), which in turn reflect the evolution of enhanced social tolerance since the Middle Pleistocene.

DOI: 10.1086/677209