Ethnomedical specialists and their supernatural theories of disease

Religious healing specialists such as shamans often use magic. Evolutionary theories that seek to explain why laypersons find these specialists convincing focus on the origins of magical cognition and belief in the supernatural. In two studies, we reframe the problem by investigating relationships among ethnomedical specialists, who possess extensive theories of disease that can often appear “supernatural,” and religious healing specialists. In study 1, we coded and analyzed cross-cultural descriptions of ethnomedical specialists in 47 cultures, finding 24% were also religious leaders and 74% used supernatural theories of disease. We identified correlates of the use of supernatural concepts among ethnomedical specialists; incentives and disincentives to patronize ethnomedical specialists; and distinct clusters of ethnomedical specialists that we label prestigious teachers, feared diviners, and efficacious healers. In study 2, we interviewed 84 Maasai pastoralists and their traditional religious and non-religious healing specialists. We found that laypersons relied on medicinal services based on combinations of efficacy, religious identity, and interpersonal trust. Further, laypersons and specialists largely used abstract concepts that were not conspicuously supernatural to describe how local medicines work. We conclude that religious healers in traditional societies often fulfill a practical and specialized service to local clients, and argue that supernatural theories of disease often reflect abstract cognition about rare phenomena whose causes are unobservable (e.g., infection, mental illness) instead of a separate “religious” style of thinking.