Near-death experiences a trick of the brain, researchers find
Psychologists find the phenomenon is the result of a reaction in the brain rather than a glimpse of the afterlife.
Near-death experiences are not paranormal but triggered by a change in normal brain function, according to researchers.
Psychologists who reviewed a range of phenomena such as out-of-body experiences, visions of tunnels of light or encounters with dead relatives, say they are tricks of the mind rather than a glimpse of the afterlife.
Researchers at the University of Edinburgh and Cambridge University say that most of the experiences can be explained by a reaction in the brain prompted by a traumatic, though sometimes harmless, event.
Caroline Watt, of the University of Edinburgh's School of Philosophy, Psychology and Language Sciences, said: "Some of the studies we examined show that many of the people experiencing a near-death experience were not actually in danger of dying, although most thought they were.
"The scientific evidence suggests that all aspects of the near-death experience have a biological basis."
The researchers say that many common near-death experiences could be caused by the brain's attempt to make sense of unusual sensations and perceptions occurring during a traumatic event.
Out-of-body experiences, for example, may happen when there is a breakdown in the brain's multi-sensory processes, and visions of tunnels and bright lights could stem from a breakdown in the brain's visual system caused by oxygen deprivation.
The new study also points to the effects of noradrenaline, a hormone released by the mid-brain which, when triggered, may evoke positive emotions, hallucinations and other features of the near-death experience.
Approximately 3% of the US population say they have had a near-death experience, according to a Gallup poll.
Near-death experiences are reported across cultures and can be found in literature dating back to ancient Greece.