Dr. Plummer's research focuses on reconstructing the behavior and ecology of extinct members of our biological family, the Hominidae. It includes a strong paleoecological component because paleoenvironmental information is integral to issues ranging from the origin of major morphological complexes (e.g. bipedalism), understanding adaptive shifts within and between hominid lineages (e.g. between hominids with gracile and robust chewing apparatuses) and elucidating the context of novel behaviors (e.g., the production of stone tools and the formation of the first archeological sites at ca. 2.6 million years ago).
           His fieldwork focuses on investigating archeological and paleontological occurrences in late Pliocene and Pleistocene sediments on the Homa Peninsula, southwestern Kenya. He is particularly interested in probing the adaptive significance of the earliest stone tool industry, known as the Oldowan. His on-going excavations at the ca. 2.0 million year old Oldowan site of Kanjera South, Kenya, have uncovered the largest assemblage of artifacts and archeological fauna from an Oldowan site outside of Olduvai Gorge, Tanzania. Manuscripts describing and interpreting the finds from Kanjera are currently in preparation.