The recent interest in the psychopharmacological underpinnings of religious experi- ences has led to both the laboratory characterizations of drug-induced mystical events and psychobiological models of religious experiences rooted in evolution and fitness. Our examination of this literature suggests that these theories may be congruent only within more modern religious and cultural settings and are not generalizable to all historical beliefs, as would be expected from an evolutionarily conserved biological mechanism. The strong influence of culture on the subjective effects of drugs as well as religious thoughts argues against the concept of a common pathway in the brain uniquely responsible for these experiences. Rather, the role of personal beliefs, expectations and experiences may interject bias into the interpretation of psychoactive drug action as a reflection of biologically based religious thought. Thus, psychobiological research proposing specific brain mechanisms should consider anthropological and historical data to address alternative explanations to the “fitness” of religious thought. A psychobiological model of the religious experience based on the concept of cognitive unbinding seems to accommodate these data better than that of a specific brain locus of religion. Keywords Psychobiology; religiousness; religious experience