Near death experiences
(NDE) first came to public light in the 1970's with the publication
of Raymond Moody's book Life After Life. Patching together
elements from different accounts, Moody described an archetypal
typical near-death experience, while noting that most accounts
include only some elements in the described archetype. The archetype
NDE included elements such as a sensation of floating out of the
body, feelings of peace and joy, a life-review that occurs very
quickly or in some altered type of time, a passage through a tunnel,
an encounter with a being of light, and seeing deceased relatives.
A previous study on near-death experiences was published in the British medical journal The Lancet in 2001. The study interviewed 344 patients who had a close encounter with death, generally through cardiac arrest. 62 of those reported some kind of near-death experience. 15 reported an out-of-body experience, 19 reported moving through a tunnel, 18 reported observation of a celestial landscape, 20 reported meeting with deceased persons, and 35 reported positive emotions. More recently the AWARE study found some fascinating similar results, discussed here.
A previous study on near-death experiences was published in the British medical journal The Lancet in 2001. The study interviewed 344 patients who had a close encounter with death, generally through cardiac arrest. 62 of those reported some kind of near-death experience. 15 reported an out-of-body experience, 19 reported moving through a tunnel, 18 reported observation of a celestial landscape, 20 reported meeting with deceased persons, and 35 reported positive emotions. More recently the AWARE study found some fascinating similar results, discussed here.
Last Sunday night the
National Geographic television channel offered us a special on
near-death experiences, entitled “Return From the Dead.” It was
the silliest treatment of the topic I've ever seen on TV. It showed
a Belgian professor Stephen Laureys as he tried various attempts to
get insights about near-death experiences.
Laureys first attempt to
get an insight about near-death experiences was truly laughable. He
went to one of those fancy expensive centrifuge machines like they
use to train astronauts to handle high g-forces during rocket
launches. He went round and round in the machine, until he got a
little tunnel vision. This, Laureys insinuated, is something that
helps to explain the part of near-death experiences in which people
often report traveling through a tunnel.
Such an insinuation is
quite ridiculous for two reasons. First, the people who have
near-death experiences are not being subjected to anything like high
g-forces, so experiments with high g-forces tell us nothing about
near-death experiences. Second, having an experience in which you
seem to speed through a tunnel is a perceptual event very different
from tunnel vision. Tunnel vision is simply where your vision is
blocked or blurry except for a clear hole in the middle of your field of
view. Tunnel vision is an example of perceptual restriction, but
those who have near-death experiences rarely report such a thing.
Instead, they often report quite the opposite, an effect of floating
out of their bodies and having their visual perceptions enhanced, as
if they could see more clearly than ever before.
Laureys next attempt to
get an insight about near-death experiences was just as silly. He
consumed some hallucinogenic substances called magic mushrooms. Then
he had some trippy experience which he compared to the transcendental
flavor of a near-death experience. Does this do anything at all to
help explain near-death experiences? No, because people who have
near-death experiences are not people who have used hallucinogenic
drugs before having the near-death experience.
Laureys next attempt to
get an insight about near-death experiences was an exercise in
irrelevancy. He went into a sensory deprivation chamber which he said
caused him to hear some voices that weren't there. This tells us
nothing about near-death experiences, because such experiences are
not preceded by periods of conscious sensory deprivation. Also, the
type of hallucinations produced by such sensory deprivation chambers
(described in this Wired story) do not resemble near-death
experiences.
Laureys next attempt to
get an insight about near-death experiences was as goofy as his first
try. To try to help understand the component of near-death
experiences in which people report floating out of their bodies,
Laureys fooled around with some very elaborate high-tech virtual
reality setup that includes a plastic dummy arm. This somehow
produces some kind of perceptual anomaly that Laureys compares to
floating out of your body. Does this do anything at all to help
explain near-death experiences? Not at all. The first reason is that
Laureys is exaggerating like crazy, because the minor perceptual
weirdness he reports is something vastly different from an experience
in which someone reports floating above their body and viewing their
body from above. The second reason is that the people who have
near-death experiences do not have them under any conditions even
slightly comparable to the condition of being hooked up to some
elaborate virtual reality machine.
Laureys approach is as
silly as someone trying to explain ghosts by filling up a room with
steam blasts and then taking pictures of steam blasts that look a
little like ghosts. That would be batty, because people who report
seeing ghosts don't see them under any such “steam rich”
conditions. Similarly, no one reports out-of-body experiences under
any conditions like the high-tech virtual reality conditions Laureys
was playing around with.
At this point in the show
Laureys waxes triumphantly about all the “insights” he is gaining
into near-death experiences from his goofy excursions into the
irrelevant.
The show ended with kind of a
“mad scientist” moment, as we see some experiments in which subjects are walloped with
oxygen deprivation. The goal is clearly to try to show that
near-death experiences are caused by oxygen deprivation.
The oxygen-starved people
are then questioned. We have some cherry-picked clips of a handful
of people mentioning something that might be relevant to near-death
experiences. There was no clip of anyone reporting something like a
full-blown near-death experience, or even a clip of anyone reporting
two different aspects of a near-death experience, nor did the
narrator mention any such person. But one woman said it was kind of
like floating around. Does this do anything to support the idea that
near-death experiences may be caused by oxygen deprivation?
Not at all, when you
consider the suggestibility factor. Previous studies have shown that
people are astonishing suggestible to figures in white coats
conducting experiments. A classic example was the Milgram experiment
which showed that people would turn a knob that they thought was
producing an almost lethal dose of electricity to someone, as long as
there was an authority figure in a white coat telling them to “please
continue.” Now let's imagine a scientist who asks for volunteers
for an experiment on whether oxygen deprivation will cause something
like a near-death experience. This will create a kind of feeling in
the volunteer's mind that the scientist hopes or expects that the
volunteer will report something a little like some part of a
near-death experience. Even if the scientist makes no mention of
near-death experiences when asking for volunteers, but merely asks
for volunteers for an experiment on oxygen deprivation, it is all too
likely that some of the volunteers would realize or suspect that the
experiment is really about whether oxygen deprivation causes
near-death experiences. In fact, there may be a selection effect in
which the people who sign up for such experiments tend to be people
wanting to help debunk near-death experiences.
So even if leading
questions were not asked to the volunteers, it would be all too
possible that we would get some answers that are largely the result
of suggestibility or an “expectation effect” in which the
volunteer slants his answers to match what he thinks are the
expectations of the scientist. And if leading questions were
answered, there would be a near certainty of some response matching
what the scientist was looking for. Suppose a scientist deprives a
volunteer of oxygen, and then asks something like, “Was it kind of
like floating about?” Regardless of what they experienced, it will
then be likely that some of the volunteers will answer something,
“Yes, it was kind of like that.”
You can do your
own research similar to that shown at the end of
the National Geographic show. Get some volunteers, blindfold them,
and spin each of them around 30 times. Then give them a questionnaire
asking questions like this:
Did you experience any of
these?
__ A white light in front
of you?
__ A feeling of joy?
__ Recall of previous
experiences?
__ A sense of floating?
__ A kind of mystical
feeling?
__ A feeling like
traveling through a tunnel?
__ Seeing one of your
relatives?
Of course, your volunteers will sense that you really want them to check one of these boxes, so almost certainly you will find a few of the questionnaire items are checked off. But you will not be entitled to claim any insight about near-death experiences from such an experiment. You will have merely shown human suggestibility.
Given the practical impossibility of randomly selecting people and subjecting them to oxygen deprivation without warning (the only way to avoid suggestibility issues and bias issues), the soundest way to determine whether oxygen deprivation produces something like near-death experiences is to check the unsolicited accounts of people who suffered oxygen deprivation while flying, mountain climbing, or diving. Such accounts (which have been written for centuries) will provide no support for the claim that oxygen deprivation can explain near-death experiences.
This scientific paper reviews the effects of oxygen deprivation (called hypoxia) and makes no mention of any effects resembling that of a near-death experience. Far from reporting the type of ecstasy often reported in such experiences, the paper reports that there was no change in the reported feelings of subjects undergoing oxygen deprivation: "self-reported feelings did not differ between the hypoxic and normoxic sessions." So the insinuation of the National Geographic TV show that oxygen deprivation can explain near-death experiences is bunk.
Laureys once co-authored a good paper on near-death experiences, one finding that the memories from them are kind of "realer than real." But judging from Sunday's TV show, his current approach to the topic seems to be to engage in various types of irrelevant busy work, and claim that these provide "insights" into near-death experiences. Acting in a similar way, you might do some experiments involving illegal aliens from Mexico, and then claim that these provided insights on aliens in distant solar systems.
No comments:
Post a Comment