Payson Sheets’ research focuses on how ancient societies in Mexico and Central America reacted to sudden massive stresses. Those stresses were explosive volcanic eruptions, droughts, and other major climate changes. Egalitarian societies, for example those in the Arenal area of Costa Rica, were strikingly resilient to the ten big explosive eruptions of Arenal Volcano. The competitive chiefdoms of Barriles in Panama were vulnerable to stress because of overpopulation and a landscape of hostility, and did not survive the relatively small eruption of Baru Volcano. Other complex societies in Mexico and the Maya area displayed varying degrees of vulnerability and resilience.
Training of graduate students in fieldwork, laboratory research, and writing articles and site reports is an important aspect of Sheets’ activities. Recent research has focused on the Ceren site in El Salvador, a village of Maya commoners buried and very well preserved by the eruption of Loma Caldera volcano in about AD 650. The most recent research seasons has focused on seed crop agriculture (maize, squash, beans, and chilies) and root crops (manioc and malanga) to the south of the village. A recent important discovery is of a sacbe, a Maya white roadway, which heads south of the village. Because he will be retiring soon, he is no longer accepting new graduate students.