 During the 1950s and 1960s, La Barre became absorbed in the study of altered states of consciousness precipitated by the ingestion of shamanistic plants from peyote and ayahuasca to magic mushrooms.Collaborating with Schultes and R. Gordon Wasson, La Barre conducted profoundly original investigations into the anthropology and archeology of altered states of consciousness.Convinced that the shamanism of Siberia was equivalent to the shamanic practices he had observed in the Americas, La Barre established a global theory of shamanism that supplanted that of Mircea Eliade.