There are many who believe that near death experiences (“NDE”) provide evidence of the existence of a spirit-soul and that those who have these close encounters with death have glimpsed another realm. Over at Brain Blogger, Jennifer Gibson discusses some recent studies of NDEs in a post titled “Light at the End of the Tunnel or Too Much Carbon Dioxide?” She notes some common features of NDEs:
Most share the same description: accelerated thought processes, peacefulness, joy, and encounters with mystical entities or deceased persons. NDEs have features associated with the phenomenon of dissociation — a psychiatric disorder in which a person’s identity becomes disconnected from bodily sensation. However, most people who report NDEs do not have a pathological mechanism contributing to the psychiatric condition.
It appears that these experiences may be triggered by high carbon dioxide levels in the brain, which in turn has marked effects on conscious functioning:
NDEs were more common in patients with higher levels of carbon dioxide on admission to the hospital. The connection with carbon dioxide suggests that NDEs might be associated with changes in the acid-base equilibrium of the brain. Previous studies have proved that changes in the brain’s equilibrium can trigger visions of bright lights and out-of-body experiences. Inhaled carbon dioxide has been studied as a psychotherapeutic agent and caused NDE-like experiences.
Gibson concludes by suggesting that NDEs may be manifestations of the supernatural:
Many believe that NDEs are proof that humans are more than just a collection of cells and neural processes and that humans have a soul or level of consciousness that is separate from the physical body. But, have the researchers in the current study debunked that theory in explaining NDEs with scientific details?
The studies that Gibson reports may not answer this question, but in a comprehensive survey of NDE studies titled “The Near Death Experience,” Glenn Roberts and John Owen observe that the specifics of NDEs often correspond to a person’s particular religious beliefs:
Schoerer (1985) presented two historical accounts of core NDEs in American Indians where the dominant imagery is of moccasins, snakes, eagles, bows, and arrows. [Asian] Indians have NDEs in which they are characteristically sent back to live because of a seeming bureaucratic mistake having been made in the after-life, and many encounter Yamraj, the Hindu king of the dead, and the Yamdoots, his messengers.
In one large and systematic cross-cultural study of 442 Americans and 435 Asian Indians who had NDEs, 140 people reported seeing religious figures; “where these [figures] were specifically identified, they were always named according to a person’s religious beliefs; no Hindu reported seeing Jesus, and no Christian reported seeing a Hindu deity.”
A person’s previously held religious beliefs, in other words, pattern the nature of the NDE, a fact which prompted Roberts and Owen to observe:
This supports the view of many authors that, whereas the central features the NDE are universally present [due to pan-human biological and neural systems], the specific imagery and interpretation is determined by the cultural expectations and beliefs of the individual.
Thus, a Muslim who has a near death experience might see Muhammad; a Buddhist may see Siddhartha; a Christian might see Jesus or an angel; a Hindu may see Krishna or Vishnu; a Lakota might see Thunderbirds, and so on. This patterning strongly suggests that NDEs are a matter of consciousness and not metaphysics.