Taphonomy - Research Methods in Human Skeletal Biology - page 237

tries to accurately deduce a cause by observing the result d through examination of the product
of a process, we attempt to replicate the process itself 3 ( Shipman, 1988; Houck, 1998 ).
The process of determining the cause of marks of unknown origin relies upon what Lewis
Binford referred to as an “argument of elimination,” a deductive process that assumes that all
possible causes have been recognized and considered, and that all but one of those possibil-
ities can be satisfactorily rejected ( Binford, 1981 :83). Such disciplined reasoning is imperative
in the study of processes related to the cause and manner of death and the disposition of
human remains in a medicolegal context. Since the reproduction of past events is critical
to forensic anthropology and other forms of skeletal biology research, an empirical paradigm
based on actualistic experiments, explained below, can provide analogues to help interpret
past processes.
Accurate interpretation of marks on bone requires the precise identification of not only the
actor (e.g., human, carnivore, rodent, wind), but also the effector (e.g., hammerstone, tooth,
abrasion). This procedure is potentially confounded by the fact that one actor may produce
numerous and varied effects, and further, the same effect may be the result of very different
processes ( Schrenk andMcGuire, 1988; Ubelaker and Adams, 1995 ). The potential for mimicry
of human activity by nonhuman agents is great, posing tremendous challenges in interpreting
skeletal material. Furthermore, bones in a naturally occurring deposition are likely to be
altered by numerous taphonomic agents. The “taphonomic signatures” of various agents
may intermingle, overlap, and obscure interpretation. Therefore, it is possible d indeed, pro-
bable d that the effects of multiple taphonomic agents will be superimposed upon one another
over time, concealing or even obliterating the taphonomic signature of other processes
( Andrews and Cook, 1985; Behrensmeyer et al., 1986 ; Schrenk and McGuire, 1988).
Weathering, trampling, abrasion, erosion, rodent and carnivore gnawing, or excavation
and laboratory procedures d even simple washing d can eradicate diagnostic evidence of
previous actors and effectors ( Behrensmeyer et al., 1986 ). In one actualistic study, three
minutes of trampling by humans in soft-soled shoes on a damp sand-and-gravel substrate
was sufficient to obscure the distinguishing characteristics of intentional cutmarks on bone
( Behrensmeyer et al., 1986 ). In a separate study, bones broken by humans to extract marrow
proved attractive to carnivores, creating an overlap in different classes of marks ( Blumen-
schine, 1988 ). In any naturally occurring skeletal assemblage, then, the distinction between
various types of marks on bone can be dubious, and reference samples resulting from unob-
served natural experiments are particularly problematic, because their ambiguous etiology
does not permit their use as reliable control collections.
To accurately and reliably identify marks on bone, researchers must gain experience with
reference collections produced by just one known actor and effector ( Blumenschine, 1988;
Pickering, 1989 ). Such investigation of past actions via examination of present systems can
be termed “ actualism ”( Micozzi, 1991; Gifford, 1992 ). Actualistic research methodology
can involve a range of approaches, including (1) ethnographic study of active practitioners
of specific behaviors, such as butchering, providing direct observation of cause and effect
relationships; (2) historical reconstruction, which can demonstrate cause and effect through
comparison of archival documentation and physical collections; (3) natural experiment, in
3 See Kroman and Symes (Chapter 8), this volume, for a discussion of how skeletal biologists also do this
with analysis of trauma.