Research on NDEs: Taylor excerpt #4

Greg Taylor writes: Throughout history, we find the same elements repeating again and again in the testimony of people who have had a brush with death. What could explain these commonalities? For skeptics, the heavenly visions of the NDE can be explained simply as a delusion: hallucinations brought on by the various physical and/or psychological burdens put on the brain by its imminent demise. But just as we saw with early scientific opinions regarding meteors, this seems to be more a way of trying to explain it away, rather than valid science. Veteran NDE researchers Dr. Bruce Greyson, Dr. Emily Williams Kelly and Dr. Edward Kelly analyzed the explanations put forward by skeptics and found that not only are none of them supported by any research evidence, but also that most are in fact contradicted by the evidence.

Bruce Greyson

In their 2009 paper “Explanatory Models for Near-Death Experiences,” the researchers systematically worked through the list of possible ‘solutions’ offered thus far, “paying special attention to how well they can account for the various features of NDEs.” These skeptical explanations can be separated into two groups – psychological-based theories, and those focusing on physiological factors. In the former category we find offerings such as the ‘expectation model’ (in which NDEs are products of the imagination, created to protect ourselves when facing threat of death, and which conform to personal or cultural expectations); depersonalization (feelings of detachment and removal from reality when facing threat of death); ‘the birth model’ (the suggestion that the tunnel, bright light and otherworldly realms of the NDE are memories of our birth experience, reproduced at death); and personality factors (susceptibility to hypnosis and dissociation, fantasy proneness, absorption, dream recall, etc.). Physiological-based explanations for NDEs include altered blood gas levels (lowered levels of oxygen, known as hypoxia or anoxia, or increased levels of carbon dioxide, known as hypercarbia); neurochemical theories (the release of endogenous endorphins, opioids or psychedelic-like chemicals such as ketamine or DMT during times of stress); neuroanatomical models (abnormal activity in parts of the brain, such as the limbic system and temporal lobes, brought on by stress and/or altered gas and chemical levels); and rapid eye movement intrusion (mentation typical of REM sleep intruding into waking consciousness).

But the researchers found that while many of these might seem like worthwhile candidates, the evidence did not support them. For instance, the birth model is contradicted by the fact that NDE accounts featuring ‘travel through a tunnel to another realm’ were just as common among those born by Caesarean section as with those born by normal vaginal delivery. Meanwhile, the expectation model is confounded by NDEs reported by children too young to have formed afterlife expectations, and also by NDEs in adults that often run sharply counter to the experiencer’s beliefs about death and the afterlife. Brain stimulation studies have not provided the support for neuroanatomical models that supporters claim, with experiences reported in such situations bearing little resemblance to NDEs. And the altered blood gas levels theory falls flat as well as NDEs sometimes occur in situations where there are no changes in blood gas levels. Furthermore, as other researchers have pointed out, “any acute alteration in cerebral physiology such as occurring in hypoxia, hypercarbia, metabolic, and drug induced disturbances and seizures leads to disorganized and compromised cerebral function [and] impaired attention,” but the NDEs reported by those who have suffered cardiac arrest “are clearly not confusional and in fact indicate heightened awareness, attention and consciousness at a time when consciousness and memory formation would not be expected to occur.”

“Almost all NDErs (near-death experiencers) report that their thinking processes were ‘faster and clearer than they ever have been before’,” Dr. Bruce Greyson notes, “despite their brain being impaired – for example, in cardiac arrest.” Indeed, one analysis of 653 NDE reports of cardiac and/or respiratory arrest patients for unprompted, spontaneous references to quality of conscious mentation during an NDE found that both figurative and abstract mentation were reported to be either preserved or markedly improved. 

Greg Taylor, “What is the Best Available Evidence for the Survival of Human Consciousness after Permanent Bodily Death?” An essay written for the Bigelow contest addressing this question. I am presenting excerpts without references, but this essay is available with footnotes and a bibliography at https://bigelowinstitute.org/contest_winners3.php.