Cultural transmission and correlational selection in Late Period projectile points from the Puna of Salta, Argentina (CE 900 - 1500)

Hernán Juan Muscio,María Varde

doi:10.2218/jls.2784

Abstract

This work proposes a methodology for documenting metric patterns of variation and trait correlation in Late Period (ca. CE 900-1500) projectile points from the Puna and pre-Puna of Salta, Argentina. In so doing, our main goal is to explain the patterns observed in terms of mechanisms of cultural evolution and selection over the design of the artefacts. We applied this methodology to assemblages of concave-based triangular projectile points from four archaeological sites whose chronologies are well established. As a result, we were able to document low degrees of variation, as well as high, positive, significant, Pearson co-variation and partial correlation coefficients between metrical traits. These results suggest a process of correlational selection that preserved an artefact design with a structure of highly integrated traits that maximised the edge-area in relation to the haft, turning these projectile points into very lethal weapons, even for potential use in interpersonal violence. This lends support to the hypothesis presented here, where replication of these projectile points occurred within a process of stabilizing cultural selection through biased transmission mechanisms that maintained the functional relations between the variables at the design scale, which in turn favoured the selection of artefacts suitable for effective weapons in a context where hunting was a strategy that optimized animal biomass acquisition, enhancing domestic herd viability.

Highlights

During the last 300 years before European contact, a particular type of lithic projectile point predominated in Northwest Argentina: concave-based triangular points (Figure 1)
Some of the obsidian in the assemblage is from sources located at more than two hundred kilometres from the sites, such as the Zapaleri and Ona sources (Figure 3). The use of these rocks shows a strong preference for high quality materials in the manufacture of this design of projectile points, even when these materials came from very distant sources
The overall variation shown by the distribution of the Coefficient of Variation (CV) around the Averaged Coefficient of Variation (ACV) indicates that when we consider the confidence intervals for each variable, the variation in the sample is not homogeneous

Summary

Introduction

During the last 300 years before European contact, a particular type of lithic projectile point predominated in Northwest Argentina: concave-based triangular points (Figure 1). These artefacts had bifacial or unifacial reduction and marginal retouch along the edges, and were made from fine-grained raw materials. This concave-based triangular design was found all over Northwest Argentina, from the mesothermal valleys to the high altitude Puna across the modern-day Provinces of Jujuy, Salta and Catamarca.

Methods

Results

Conclusion