Charting Andean violence in space and time
This long-term project charts patterns in violence over time and space in the ancient Andes by compiling rates of cranial trauma from dozens of published studies by bioarchaeologists. Cranial trauma is the most common form of injury that can be associated with interpersonal violence in the Andes. Patterns in the growing body of research allow a scope of analysis far beyond the insights of any single study.
Currently, the dataset compiles information from over 115 studies and over 140 sites dating from the Archaic to Inca periods, and encompasses over 11,000 individuals (> 8500 adults). In the aggregate, this large sample shows very interesting patterns. Rates of cranial trauma vary a great deal over space and time, and range from zero to more than 60% of adults in Andean skeletal samples. Over time, there were dramatic peaks and lulls in the frequency of violence. Coastal and highland trajectories are quite distinct. Violent injury for men, women, and children was patterned in different ways.
Log odds of trauma through time for males (blue) and females (red). Image and analysis by Tom Snyder.
For example: males usually have higher trauma rates than females, but the rates correlate across studies, and they move in tandem over time. So, although males and females might not have been injured in the same kinds of situations, the processes affecting the two sexes appear related.
These patterns are explored in my book War, Spectacle, and Politics in the Ancient Andes (2022) and in a forthcoming article with Tom Snyder (PNAS, 2024). The version of the cranial trauma dataset used in the book is published here. An earlier version of the dataset was published with Tiffiny Tung (2013, J Archaeol Res). The dataset continues to grow as new bioarchaeology work comes out.