He received his bachelor's degree from Washington & Jefferson College, and his Ph.D from the University of the Witwatersrand, South Africa in 1984.
His research focuses on the hominin fossil record, during the Pliocene and early Pleistocene and the reconstruction of phylogenetic relationships through dental morphology.
Among his most important works, has been the analysis of dental microwear in order to reconstruct early hominin dietary habits.
Together with his former graduate student, David Strait, he has also published influential studies of early hominin phylogenetic relationships.
He has also authored the widely used anatomical textbook, Regional Human Anatomy: a Laboratory Workbook for Use With Models And Prosections (McGraw-Hill College, ISBN 0-07-243888-6).