Robert D. Leonard

Basic incompatibilities between evolutionary and behavioral archaeology

Schiffer (1996) recently proposed that, despite some incompatibilities, considerable common ground exists between behavioral archaeology and evolutionary, or selectionist, archaeology. He concludes that there is no fundamental reason why the two approaches cannot work in concert to explain human behavioral change. There are, however, several important reasons why the two programs, at least as currently conceived, cannot work together in any thoroughly integrated fashion. Although both programs employ inference, behavioral archaeology conflates the distinct roles of configurational and immanent properties, searches for nomothetic answers to questions about human behavior, overlooks historical contingency when inferring and explaining the nature of past behavior, and in some cases seems to fall back on vitalism as the mechanism of change. Evolutionary archaeology employs immanent properties inferentially, explicitly acknowledges the importance of the historical contingencies of configurational properties, explains human behavior as being time- and spacebound, and calls upon selection and drift (transmission) as the mechanisms of change. Any attempt to integrate the two approaches must begin by addressing these basic differences.

Specialized ground stone production in the Casas Grandes region of northern Chihuahua, Mexico

Previous research has identified specialized production of prestige goods during the Medio period (A.D. 1200-1450) in the Casas Grandes region of northwestern Mexico and the American Southwest. We evaluate the organization of production of two functionally equivalent types of trough metates from Paquimé, Chihuahua, Mexico, using the standardization hypothesis, i.e., the premise that products produced by specialists have less variation than those manufactured by less-specialized producers. We find that the morphology of one of the metate types (Type 1A metates) is statistically more standardized than the other (Type 1B metates). We then compare the Paquimé metates to those manufactured by generalized producers from the Mimbres Valley region of New Mexico. We find that Mimbres through-trough metates and the Type 1B metates from Paquimé have a similar degree of morphological variation, but that the Type 1A Paquimé metates are morphologically more standardized, indicating that specialists produced them. We conclude that specialized production in the Casas Grandes region was not limited to prestige goods but was instead a fundamental organizing principle of the Medio period economic system, reflecting the presence of a well-established social hierarchy and exchange system.

Flaked Stone and Social Interaction in the Casas Grandes Region, Chihuahua, Mexico

This analysis usesflaked stone artifacts to gain insight into the social and economic structure of the Casas Grandes region, northern Chihuahua, Mexico. It begins by considering the intrasite variation in flaked stone reduction at Galeana, a large site near the modern town of Galeana. The analysis of debitage and cores from Galeana indicates that the assemblage is primarily the product of hard hammer, generalized reduction of locally available materials. Differences within the assemblage indicate the presence of spatially distinct reduction areas, with initial core reduction occurring in open areas, and then continuing in room blocks. We then compare the Galeana assemblage with the flaked stone assemblage from the site of Paquime" (Casas Grandes), Chihuahua. The analysis indicates that the reduction technique employed at both sites is similar, but that the PaquEme" assemblage is characterized by a greater proportion of cryptocrystaline silicates and obsidian than the Galeana assemblage. Furthermore, much of the raw material from Paquime" does not appear to be locally available. We conclude that the prehistoric inhabitants of Paquime" had greater access to cryptocrystaline silicates and obsidian acquired through trade than did the inhabitants of Galeana. This evidence indicates that the economic pattern evident at Paquime" did not extend to Galeana and supports the idea that Paquimes economic and political influence over other Casas Grandes sites was limited beyond a 30-km radius.

The Sample Size-Richness Relation: A Comment on Plog and Hegmon

Plog and Hegmon (1993) focus on my research (Leonard 1989) on Black Mesa, Arizona, faunal assemblages as part of a broader critique of the work of a number of researchers who consider the effects of sample size on assemblage richness values. I suggest that their critique is problematic for a number of reasons, primarily statistical, but also because they do not provide an alternative hypothesis for the observed pattern.

Models, Definitions, and Stylistic Variation: Comment on Ortman

Ortmans comments concerning the evolutionary archaeology model of style in his study of the textile metaphor in Mesa Verde pottery designs are based upon a misunderstanding of the assumptions of the neutral model of style. We clarify these assumptions and explain why Ortmans study is not a test of the model.

Theory, models, explanation, and the record: response to Kohler and Sebastian

We belive that most of Kohler and Sebastians concerns regarding our research are attribuable to differences in how we perceive the relation between theory, models, explanation, and the archaeological record. Other differences we attribute to misunderstandings of both our work and selectionist theory in general. We finaly conclude that differences in our opinions on these issues represent broader problems in our discipline

Characterizing Data Numerically: Descriptive Statistics

While visual representations of data are very useful, they are only a beginning point from which we may gain more information. Numerical characterizations allow a more formal means of both describing a distribution and comparing two or more distributions. Numerical description ultimately allows us to make the inferences we desire. These numerical characterizations are termed either statistics or parameters. Statistics are descriptions of the constructed characteristics of a sample, whereas parameters refer to the characteristics of a population. A population is a group of data defined in time and space. Do not confuse this use of the term population with its use in biology and physical anthropology. Statistical populations are not things. They are not people, or animals, or rocks, or pots. They are data. For example, the length of Folsom points manufactured during the Paleoindian occupation of the New World could be considered a population. The size of thimbles used in New York during the Historic period is another possible population. As you can see populations can vary in their scope from data about all of a class of objects ever in existence to data on a more limited subset of objects. We could even define a population at the scale of a site (e.g., the frequencies of each species of animals consumed at a site could be considered a population.) In contrast a sample is a subset of a population that does not contain all of the population’s members. For example, the animals reflected by bones recovered from a site