About Research
Dr. Spencer is a Research Associate with the Institute of Human Origins. His research focuses on the mechanics and evolution of the jaws and teeth in primates. Primates, including hominids, exhibit obvious diversity in the form of their skulls. Much of this diversity results from adaptation to the varying mechanical demands of differing diets. An understanding of the relationship between craniodental form and diet is therefore crucial to our inferences about feeding behavior in past species.

Dr. Spencer's work addresses these issues by developing and testing the biomechanical concepts that underlie interpretations of jaw function and evolution. Of particular interest is how skull shape influences the way chewing forces are generated and distributed within the jaws, and how the morphology of the jaws and teeth may be adapted to resisted the stresses that occur during feeding. This work utilizes a range of methodological approaches, including biomechanical modeling, comparative morphology, and experimental techniques.

Current work includes research into the form and function of tooth roots, studies of the influence of chewing muscle function on patterns of temporomandibular joint loading, and a collaborative project that seeks to test a range of biomechanical hypotheses through the development of a Finite Element model of the primate skull.

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Select Publications
Grine, F.E., Spencer, M.A., Demes, B., Smith, H.F., Strait, D.S., Constant, D.A. (in press)
Molar enamel thickness in the chacma baboon, Papio ursinus (Kerr 1792). American Journal of Physical Anthropology.

Spencer, M.A. (2003)
Tooth root form and function in platyrrhine seed eaters. American Journal of Physical Anthropology. 122: 325-335.

Spencer, M.A. and Ungar, P.S. (2000)
Craniofacial morphology, diet and incisor use in three Amerind populations. International Journal of Osteoarchaeology. 10: 229-241.

Spencer, M.A. (1999)
Constraints on masticatory system evolution in anthropoid primates. American Journal of Physical Anthropology. 108:483-506.

Spencer, M.A. (1998)
Force production in the primate masticatory system: electromyographic tests of biomechanical hypotheses. Journal of Human Evolution. 34:25-54.

Spencer, M.A. and Spencer, G.S. (1995)
Video based three-dimensional morphometrics. American Journal of Physical Anthropology. 96:443-453.

Spencer, M.A., and Demes, A.B. (1993)
Biomechanical analysis of masticatory system configuration in Neandertals and Inuits. American Journal of Physical Anthropology. 91:1-20.

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Contact: Mark A. Spencer

Related Links: Institute of Human Origins