One of the more useful comparative and integrative concepts in Maya ceramic studies is that of the ceramic “sphere.” The sphere concept was originally developed and elaborated to permit correlation of ceramic complexes into horizons, in order to resolve questions of priority and contemporaneity (Willey, Culbert, and Adams 1967: 306). Its definition emphasized typological similarities and dissimilarities between ceramic complexes: a ceramic sphere “exists when two or more complexes share a majority of their most common types” and “makes possible the recognition of two degrees of content similarity: high... and little or no. . .” (ibid.). It follows, then, that the content of a ceramic sphere “is the sum total of all the types and modes of its member complexes. The diagnostic content of the sphere consists of those elements shared by all or some of the complexes upon which decisions about membership in a sphere are based” (Willey, Culbert, and Adams 1967: 307; basically, these “elements” constitute the “horizon markers”). The idea was that information on the total number of “elements” and the proportions of those that are shared, partially shared, and unique would be useful for studying the development and spread of ceramic traditions. Further, variations in spheres’ areal extent could reveal the direction and intensity of culture contacts.
In contrast to its originally intended use, as a building block for defining horizons, the sphere concept has proven to be informative in and of itself. Spheres and their cultural inferences have been operationalized most effectively by Joseph Ball (1976) in his summary discussion of the pottery of Barton Ramie in the Belize River Valley in west-central Belize. Sphere identifications begin with recognition of diagnostic versus nondiagnostic (or general) ceramic types in the complexes in question. Diagnostic types are abundant and widely shared among the ceramic complexes that constitute a sphere, and a given type can be part of the content or affiliation of more than one sphere (Ball 1976: 324). Consequently “[Cjeramic spheres essentially are quantitatively rather than qualitatively defined”; in other words, spheres are defined not by the mere presence of a particular type but by its abundant, shared presence in numerous complexes (ibid.). Thus it is not ceramic types or groups that have a sphere affiliation, but rather entire complexes. Finally, it is important to remember that ceramic spheres are “spatiotemporally dynamic rather than static constructs. . . . [they] should be expected to move, expand, and/or contract over the course of their existence” (ibid.).
Using what he called a “more or less arbitrary standard of judgment,” Ball (1976: 323) created three categories of sphere membership (or exclusion) into which a given complex can be placed:
1. “Definite, full sphere membership” means that a complex has roughly 60 percent or greater content similarity (via either typological identification or the equivalent) between two complexes. It means that “a significant proportion of locally produced or imported, domestic utilitarian pottery (such as would include water-carrying and storage vessels, dry storage vessels, everyday service vessels for food preparation and presentation, and so on) as well as, or in contrast to, more specialized and rarer fine and/or ceremonial wares was common to the compared complexes.”
2. “Peripheral sphere membership or exclusion” can occur when there is roughly 40-50 percent content similarity between two complexes. In this ambiguous situation, decisions about sphere membership depend on the subjective judgment of the analyst.
3. “Definite exclusion from a sphere” occurs if there is roughly 40 percent or less content similarity. As Ball notes, this circumstance demands careful attention, because it may reflect a variety of possible cultural situations, including importation of luxury, funerary, ceremonial, or specialized utilitarian pottery; reciprocal exchange; foreign intrusion; common derivation from an earlier shared tradition; and so forth.
The 1965 Guatemala City Maya ceramic conference participants identified, with very limited data, characteristics of southern lowland Terminal Classic pottery in terms of spheres, and many of their observations are still useful today. In particular, the conferees noted that the period reflected loss of the widespread “ceramic unity” evident in the preceding Late Classic period, particularly in its Tepeu ceramic sphere, and this gave way to
Three separate spheres of limited areal extent. ... A striking characteristic of all of the spheres is the drastic reduction or total disappearance of the tradition of polychrome painting. . . [and] a high degree of local differentiation after the disappearance of polychomes. . . . [This] ‘ceramic disruption’
. . . correlates. . . with the breakdown of the stela cult, monumental construction. . . [and] loss of cultural cohesiveness (Willey, Culbert, and Adams 1967: 311).
World History
