Biological and Cognitive Underpinnings of Religious Fundamentalism

Religious fundamentalism involves firm adherence to a set of beliefs held to convey unassailable truths, and although earlier lesion work had implicated the ventromedial prefrontal cortex (vmPFC) in representing religious belief, the cognitive route by which prefrontal damage produces such rigidity remained unclear. Administering a validated religious fundamentalism scale to 119 veterans with penetrating traumatic brain injury and 30 healthy combat controls, the authors tested whether vmPFC damage increases fundamentalism and whether cognitive flexibility and trait openness mediate that relationship. Patients with predominantly vmPFC lesions did report higher fundamentalism than patients whose lesions spared the prefrontal cortex, but it was the extent of dorsolateral prefrontal (dlPFC) damage that influenced fundamentalism indirectly, by diminishing cognitive flexibility and openness. The study reframes fundamentalist belief as arising in part from general cognitive capacities supported by the dlPFC, indicating that a diverse and adaptable religious commitment depends on the ability to revise beliefs rather than on any dedicated religious faculty.