Artifact Scatters, Adaptive Diversity, and Southwestern Abandonment: The Upham Hypothesis Reconsidered

Abstract

Sites discovered by archaeological surveys are often recorded and interpreted in terms of site types. Problems with the taxon "limited activity site" are reviewed. Quantitative investigation of the nonassemblage characteristics (e.g., site size, artifact density, and artifact clustering) of thirty-four artifact scatters near Grasshopper Ruin in east-central Arizona shows that two subtypes--sherd and lithic scatters and lithic scatters--are formed in fundamentally different ways and, therefore, should not be combined analytically. Next, Upham's hypothesis of Southwestern abandonment, which uses regional percentages of limited activity sites as evidence, is critically examined. In view of the diverse formation processes of so-called limited activity sites and the nonsystemic factors that affect their regional relative frequencies, there appears to be no empirical support for Upham's model. Additional discussion focuses on several irresolvable empirical and conceptual problems with the adaptive diversity hypothesis.