Explaining corrugated pottery in the American Southwest: an evolutionary approach

Abstract

Corrugated pottery is a unique utility ware made by leaving construction coils unobliterated, and manipulating these exposed coils to produce a rough exterior surface. Ancestral Puebloan populations in the American Southwest made this pottery in various forms between AD 650 and 1450. Although archaeologists have tried to explain corrugation for over 100 years, none of these explanations has proven satisfactory. I employ an evolutionary approach in an attempt to explain the rise and fall of corrugated pottery.Using analyses of ancient pottery, experiments with modern replicas, and syntheses of published data, I document that corrugation developed gradually from plain ware through a series of innovations in the size of coils and how they were applied and manipulated. Initially, corrugation appeared in the southern Mogollon region as wide, filleted, and unindented bands on jar necks, and spread north into the Anasazi areas of the Colorado Plateau. The development of overlapped and indented neck bands during the ninth and tenth centuries ultimately led to the use of these techniques over the entire exterior surface during the eleventh century producing full-body, indented corrugation. Full-body corrugation spread rapidly across a large area of the Colorado Plateau, and remained dominant until the fifteenth century when a return to plain pottery occurred. The development of corrugation coincided with an increase in the use of these vessels to cook food.Although most of the innovations appeared first as decorative elaborations, some also affected the cost and performance of the vessels. The use of narrower and overlapped coils increased the time required to form a vessel over the earlier plain vessels. However, the extension of the textured surface to the upper body and basal parts of vessels significantly improved control over cooking and the use-life of vessels respectively.Explanations of corrugation emphasize how the environment with which corrugated pottery interacted changed through time, and how these changes affected innovation rates, and the selection or drift of particular corrugation variants. In formulating explanations, I address four problems: the advent of neck banding, experimentation with neck banding, the rapid adoption of full-body corrugation, and the return to plain-surfaced pottery.