Complexity and possession: Gender and social structure in the variability of shamanic traits.

Singh deploys cultural evolution to explain recurrent features of shamanistic trance forms, but fails to substantively address important distinctions between these forms. Possession trance (vs. trance without possession) is disproportionately female-dominated and found in complex societies. The effects of cultural conditions on shamanism thus extend beyond its presence or absence and are vital for modeling its professionalization and spread.