Possession trance covaries with measures of social rigidity in the Ethnographic Atlas

Possession trance, an altered state of consciousness where a person believes an alien spirit resides in them, is often pathologized in Western medicine but has been linked by anthropologists to social marginalization in complex, rigid societies. This study analyzes cross-cultural data from the Ethnographic Atlas and two cultural phylogenies using gradient boosting, Bayesian hierarchical models, and phylogenetic comparative methods. Results support a correlation between possession trance and several proposed social factors, but no evidence for co-evolution between possession trance and those factors was found.

Study at a glance

Abstract

Possession trance is an altered state of consciousness resulting from spirit possession, belief in an alien entity residing in the self. Though treated as an individual psychopathological condition in Western medicine, cultural anthropology has long tied possession trance, and trance and possession phenomena in general, to marginalization by increasingly complex and inflexible social structures. This paper revisits these claims by analyzing cross-cultural data from the Ethnographic Atlas and two cultural phylogenies with the use of gradient boosting, Bayesian hierarchical generalized linear models, and phylogenetic comparative methods. The findings support a correlation between possession trance and many, though not all, social factors proposed in the literature. I do not find evidence for the co-evolution of possession trance and such factors.