The Signaling and Inheritance of Cooperation: Artificial Cranial Modification among Altiplano Foragers

Summary

We report on the recent archaeological discovery of a 7000-year-old population of hunter-gatherer burials and discuss the key insights they offer into how hunter-gatherer societies may have maintained cooperative structure against evolutionary odds. Sixteen human burials interred at the site of Soro Mik'aya Patjxa in the Andean Altiplano of Peru consistently exhibit intentional artificial cranial modification (ACM)—the irreversible shaping of human crania during infancy. Our analysis of cranial form, burial context, and skeletal properties indicates that the ACM existed among a relatively egalitarian hunter-gatherer population and cannot be linked to hierarchical social structure. These observations in conjunction with fundamental properties of ACM—its unfakability, visibility, and vertical inheritance—suggest that ACM served as an honest visual index of an individual's enculturation including their understanding of moral codes that mitigated the inherent risks of non-kin cooperation. Groups that engaged in ACM would have enjoyed competitive advantages over those that did not, and offspring who received ACM from their parents would have inherited those group advantages. The entailed mechanism of kin and non-kin cooperation helps resolve the question of how a seemingly trivial form of human body modification persisted for more than seven millennia and radiated throughout South America.

This Resource is Part of the Following Collections

• Society for American Archaeology 82nd Annual Meeting, Vancouver, BC (2017)   •
• Archaeological Perspectives on the Evolution of Forager Cooperation

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Record Identifiers

Abstract Id(s): 13274