Gregory is a specialist in the anthropology of Lowland South America while engaging with theoretical frameworks that enable cross-regional comparison and dialogue with other social sciences.

Based on long-term fieldwork in Amazonian Ecuador, he investigates the collective and personal experiences of managing witchcraft, the conditions of transformation of an esoteric Amerindian tradition, and the various uses of writing along a neo-colonial frontier.

As part of the first topic, he explores how people living in village communities of relatively recent creation deal with uncertainty related to witchcraft at a time of increasing reliance on state-derived institutions and market exchanges. Within the second topic, Grégory analyses the tension between a shamanism understood as an esoteric mode of action at the service of the defensive and offensive interests of a person, and a shamanism understood as the possession of a fixed corpus of cosmological knowledge characteristic of an ethnic group and at the service of the common good. Concerning the third topic, Grégory investigates how different institutions shape writing as a technique to transmit knowledge and as a technique to establish power. He focuses on the diverse textual ideologies that underpin the creation and uses of magical grimoires, bureaucratic documents, cultural compilations and various kinds of autobiographic writing.

Gregory engages in inclusive collaboration at each step of the research process. As part of collaborative work, he participated in documenting the Jivaroan Shuar oral traditions in the Andean foothill and Amazonian forest of south-eastern Ecuador.

His contribution to the project “Justice, Morality, and the State in Amazonia” compares the different regimes of justice which coexist among Aénts chicham people (Shuar and Shiwiar).