My current research centers around the
problem of how behavior can reliably be inferred from skeletal structure, with
special focus on the origin and evolution of human locomotion, hand 
function, and craniofacial biomechanics. My long-range goals include the recovery and
analysis of relevant fossils, and investigating the factors influencing bone
morphology during growth with the aim of improving our understanding of the
adaptive history of human evolution.
Problems of particular interest include the origins of bipedality and
how it changed in subsequent hominins, the abandonment of arboreality, the
evolution of limb proportions, the biomechanics and origin of tool use, and
craniofacial adaptations for diet in hominin evolution.
My main current research projects include
paleoanthropological fieldwork in Koobi Fora, Kenya, an investigation into the
relation between function and trabecular bone structure, an interdisciplinary
project investigating primate craniofacial biomechanics through finite element
modeling and strain gage analysis.
Paleontology
Fieldwork
New fossil discoveries form one of the foundations of our
understanding of human evolutionary history, as they provide raw data about the
past. I have been involved in field
research in
Supported by the National Science Foundation.
Trabecular Bone
Functional Morphology
Researchers continue to disagree over how to reconstruct
the locomotor behavior of fossil hominins mainly because some interpret apelike
features of the hominin skeleton as evidence of apelike behavior, while others
interpret the apelike features as primitive retentions with little or no
functional relevance. Because experimental data show that trabecular bone
structure (the spongy bone matrix within joints, as seen in this image) is
related to functional loading of joints, analysis of 3D trabecular structure
offers a new way of testing longstanding hypotheses about the evolution of
locomotor behavior in fossil hominins. Our current research investigates
specific details of the relationship between functional loading and trabecular
bone structure, and the structure in fossil hominins and comparative extant
species.
Supported by the National
Science Foundation.
Primate
Craniofacial Biomechanics
Although there is no doubt that aspects of skull shape
are structurally related to resisting the stresses from biting and chewing,
relatively little is known about these stresses in primates and humans. As part
of a collaborative research project, I am exploring the utility of Finite
Element Analysis (FEA), in conjunction with experimental data, in modeling
stresses and strains in the primate facial skeleton. This work will help us
test hypotheses about how the face and skull are strained during biting and
chewing, how variation in biomechanical factors (e.g., bone mechanical
properties, and muscle force, geometry, and timing) influence stresses, and how
specific aspects of bone structure (e.g., postorbital bar, degree of prognathism) influence stress distributions. FEA promises
to be a useful tool for examining the biomechanical significance of unique
features of fossil hominin skulls.
Supported by a HOMINID grant
from the National Science Foundation.