Three Faulty Studies on Near-Death Experiences

Several readers of this blog have left comments trying to get me to comment on a recent study claiming to offer a "neuroscientific model of near-death experiences." The paper is behind a paywall, and my policy is never to pay for neuroscience research behind a paywall. Given the very strong tendency of neuroscientists these days to produce poorly designed junk science studies using bad methods, this is good policy for anyone to follow. Making a serious misstatement, the abstract of the paper makes no mention of anything that should make us suspect the paper is worth paying $30 for, and it fails to mention any new experimental research. 

I can, however, make some comments on previous papers co-authored by the main author of the study (Charlotte Martial), papers that are publicly available.  Her  2020 paper "Near-Death Experience as a Probe to Explore (Disconnected) Consciousness" is one that very badly  mischaracterizes near-death experiences. She has a 3D chart in which a near-death experience is depicted as a state of the lowest wakefulness and the lowest connectedness. But contrary to such a description,  it has been massively reported by those having near-death experiences that they had a super-high state of wakefulness and a super-high state of connectedness, with the description "realer than real" sometimes used.  The study here backs up such claims. 

Martial clumsily tries to define wakefulness as being a state of eyes open, but that is not correct. You can be wide awake with your eyes closed. Often awaking in the middle of the night for an hour or more,  I routinely do some of my best thinking while lying awake in bed with my eyes closed, in a state of high wakefulness. Martial also makes some arbitrary definition of "connectedness" that seems to correspond to having regular sensory experience. The definition makes no sense in the context of near-death experiences, where people report a very high sense of connectedness that is different from regular sensory experiences.  

In her 2020 paper Martial makes the extremely inaccurate statement that "no empirical study has confirmed that NDEs include some real external events." To the contrary, very many accounts of near-death experiences have discussed people describing details of the real world (including real events) during out-of-body experiences, events and details they should not have been able to have known about during some state of what looked like unconsciousness or cardiac arrest occurring during their near-death experiences. Many such accounts are described in my post here. Many other such accounts can be read in my series of 31 posts you can read here, such as my post here. We may presume that whatever "model" of near-death experiences Martial has described in her new paper behind a paywall, it probably involves confusions and mischaracterizations and  misstatements similar to those in her 2020 paper "Near-Death Experience as a Probe to Explore (Disconnected) Consciousness," giving an additional reason not to spend thirty dollars to pay for a look at her latest "model." 

We have in her 2020 paper  vacuous skimpy hand-waving that ignores one of the central reasons why neuroscientists cannot explain near-death experiences that are rich in very vivid memories: the fact that such experiences often occur when the brain has electrically shut down, during the state of asystole that occurs within 15 or 20 seconds after the heart stops. Martial states, "Although memory theories have difficulties explaining NDEs and their resulting rich memory,  an answer can be provided by theories demonstrating the importance of the medial temporal lobe for memory encoding and retrieval." This is a strange statement indeed. Theories do not demonstrate things; facts and observations demonstrate things.  

No neuroscientist has any detailed credible theory of how a brain could do any such thing as memory encoding or memory retrieval, and there is no understanding of how any of the endless types of things humans learn and experience could ever be translated into brain states or synapse states. And if the brain were to do any memory encoding, it would require the normal electrical operation of the brain, which is often shut down while people are having near-death experiences, while brain waves (as measured by EEG devices) flatline.  So it is false to claim as Martial did that "an answer can be provided by theories demonstrating the importance of the medial temporal lobe for memory encoding and retrieval." Neuroscientists are at an utter loss to credibly explain how any brain could form a memory during everyday living, and trying to explain how an electrically inactive brain could form a memory would be harder than explaining how a jet without any fuel could fly between cities. Microscopic examination of human brain tissue has never found any trace of stored memories and never found any trace of learned human knowledge. 

The insinuation that the medial temporal lobe is necessary for memory is incompatible with the facts of epilepsy surgery outcomes. The  temporal lobe is often removed to treat severe epilepsy, without any damage to memory or cognition, as I discuss in my post here. A paper states, "The data do not confirm concerns that patients undergoing temporal lobe epilepsy surgery are likely to develop accelerated memory decline over the longer term." See the appendix of this post for a discussion of how the data discredits the claim that the medial temporal lobe is vital for memory.  

A 2018 paper co-authored by Martial had the misleading title "DMT Models the Near-Death Experience." The paper is critically discussed in my 2018 post here, where I find quite a few reasons for rejecting its validity. The study group sizes used were the usual way-too-small study group sizes used in neuroscience studies. There was one group of 3 subjects receiving 7 milligrams of DMT, another group of four subjects receiving 14 milligrams of DMT, and another group of five subjects receiving 20 milligrams. In a properly designed study of this type every study group would have consisted of at least 20 subjects.  

The amount of DMT given in the study was utterly unrealistic for any discussion of a natural release of DMT.  The question of DMT in the brain was clarified by David E. Nichols in a paper he authored in the Journal of Psychopharmocology. Speaking of DMT (also known as N,N-dimethyltryptamine) in the paper Nichols says, “It is clear that very minute concentrations of N,N-dimethyltryptamine have been detected in the brain, but they are not sufficient to produce psychoactive effects.” Addressing speculations that DMT is produced by the tiny pea-sized pineal gland in the brain, Nichols points out that the main purpose of the pineal gland is to produce melatonin, but the pineal gland only produces 30 micrograms of melatonin per day. But the pineal gland would need to produce about 20 milligrams of DMT (about 660 times more than 30 micrograms) to produce a mystical or hallucinatory experience. “The rational scientist will recognize that it is simply impossible for the pineal gland to accomplish such a heroic biochemical feat,” says Nichols. In the article in which he states that, it is noted that “DMT is rapidly broken down by monoamine oxidase (MAO) and there is no evidence that the drug can naturally accumulate within the brain.” Strassman attempted to detect DMT in the brains of 10 human corpses, but was not able to find any.

Given these facts, it is quite absurd to suggest that near-death experiences are being produced by DMT in the brain. We have about 100,000 times too little DMT in our bodies for DMT-produced experiences to appear. Web pages speculating that near-death experiences may be produced by DMT will typically tell us that DMT has been detected in rat brains, failing to tell us how much DMT was detected (merely trace levels 100,000 times too small to produce any remarkable mental experiences).

What Martial and her co-authors did in this paper is to give subjects an amount of DMT more than 1000 times greater than the human body could ever naturally produce.  This makes no sense from a standpoint of trying to naturally explain near-death experiences.  The paper's claim that the DMT "modeled" near-death experiences is not correct. In my post here I point out nine ways in which near-death experiences differ from the experiences reported by the people getting DMT. 

In order for us to judge how closely these DMT-induced experiences resembled near-death experiences, we would need to have first-hand accounts of the experiences from the people who had the experiences. It would have been very easy for a scientific study to have produced such accounts. Martial and her colleagues could have simply had each of his subjects write (or recite into a tape recorder) a 500-word or 1000-word account describing their experiences. Then those accounts could have been included verbatim as appendixes in the scientific paper. If that had been done, then we would be able to judge how closely the experiences resembled near-death experiences, not only by looking for points of similarity between DMT experiences and near-death experiences, but also by looking at things that happened during the DMT experiences that did not happen in the near-death experiences. But since Martial and her colleagues have not included any such accounts in their DMT paper, we have no way of accurately judging how closely the DMT experiences resemble near-death experiences. It could be that the DMT experiences were filled with all kinds of things that never happen in near-death experiences.

In fact, when we read previously published accounts of DMT experiences, such as those given here, we have reason to believe that DMT produces all kinds of weird stuff that doesn't show up in near-death experiences. The page includes all kind of random hallucinatory stuff such as someone seeing his house unbuilding itself, someone reporting that there were slinky toys everywhere, someone reporting his computer looking sad, someone reporting his friends melting, and someone being swallowed by a being like an octopus.

We can imagine what probably went on with this experiment:

(1)  Subjects were probably told that they would be involved in an experiment in which scientists would test the hypothesis that DMT trips produce experiences like near-death experiences.  This would have created a sense in the subjects that scientists were hoping that the subjects would report something like a near-death experience, so that the paper could publish a positive effect and get published. 

(2) After being given DMT, subjects were then asked a series of questions about their experience, with each question being an item on the Greyson Scale (listing features of near-death experiences). 

(3) Wishing to please the scientists that they were involved with, the subjects probably gave much higher percentages of "yes" answers than they would have given under a different questioning arrangement. 

When a study like this is done, it is vital that the researchers tell us exactly what the subjects were told about the experiment prior to the experiment being conducted.  We are told that the subjects were recruited. Were the subjects told that the experiment would be an attempt to see whether DMT use would produce reports like those given in near-death experiences? Such information might have produced a magnet effect, in which the people agreeing to participate would be more likely to be those hoping to help discredit near-death experiences, by reporting something like near-death experience effects after taking DMT. Such information might have also produced an expectation effect in which the subjects thought the experimenters were hoping to get reports like those of near-death experiences.    But the paper co-authored by Charlotte Martial does not tell us this vitally important information about what the subjects were told about the experiment before it was conducted. 

Lacking such information, we may presume that the subjects either were told that the experiment was one that would attempt to find whether those taking DMT would make reports like near-death experience reports, or that the subjects knew that such a thing was the goal of the experiment, even if they were not told that by the experimenters.  In academia research subjects are typically students in a particular department, and word gets around in a department about what type of experiments are being done, and what the experiments are hoping to find.  If the researchers had taken measures to make sure that the subjects were "blind" about the purpose of the experiment, that would have been a strong point in favor of linking DMT experiences and near-death experiences.  But since no such measures are reported in the paper, we can presume that they were not taken. 

Another study on near-death experiences co-authored by Martial takes a very different approach.  The paper is entitled "

EEG signature of near-death-like experiences during syncope-induced periods of unresponsiveness." 22 subjects were trained in some technique by which you can cause yourself to faint. The subjects were connected to EEG machines that read brain waves, and were then encouraged to cause themselves to faint, using the techniques they had been trained in. 

The paper fails to provide any good evidence that any of these subjects had a near-death experience.  We have no quotations from any of the subjects, nor any narrative describing what any subject experienced.  The reported average length of time the subjects fainted was only 16 seconds, that being an interval of time so short it should cause us to doubt that anyone of the subjects had something like a near-death experience. 

The subjects were asked questions corresponding to the items on the Greyson Scale, questions such as "Did scenes from your past come to you?" and "Did you see or feel surrounded by a brilliant light?" The responses do not indicate any strong effect of matching the characteristics of near-death experiences. 

The Greyson Scale questions are questions with three possible answers.  Below is the beginning of a Table 1 in Greyson's original paper listing questions corresponding to the scale.  For example, in response to question 8 ("Did you see or feel surrounded by a brilliant light"?) the choices are 2("Light clearly of mystical or other worldly origin"), 1 ("Unusually bright light") or 0 ("Neither.")

It is vital that any researcher asking subjects questions from the Greyson Scale (like the questions above) give us exact data on how high the numbers were in the answers given. But Martial failed to do that.  Her paper merely reports what fraction of the respondents answered either 1 or 2 to each of the questions corresponding to the Greyson Scale.    Failing to report the data that you collected (when it is extremely easy to do so) is a very bad defect in a research paper. 

The data that we get in the paper is below:

“Did time seem to speed up or slow down?" -- 22 out of 24 answered either 1 or 2. But the question asked does not exactly correspond to anything on the Greyson Scale, where the corresponding question is "Did time seem to speed up?"

"Were your thoughts speeded up?"  -- 10 out of 22 answered either 1 or 2. 

"Did scenes from your past come back to you?" -- 4 out of 22 answered either 1 or 2. 

“Did you suddenly seem to understand everything? -- 0 out of 22 answered either 1 or 2. 

Did you have a feeling of peace or pleasantness? -- 15 out of 22 answered either 1 or 2. 

Did you have a feeling of joy? -- 6 out of 22 answered either 1 or 2. 

Did you feel a sense of harmony or unity with the universe? -- 8 out of 22 answered either 1 or 2. 

Did you see, or feel surrounded by, a brilliant light? -- 2 out of 22 answered either 1 or 2. 

Were your senses more vivid than usual?  -- 11 out of 22 answered either 1 or 2. 

Did you seem to be aware of things going on elsewhere, as if by extra sensory perception? -- 0 out of 22 answered either 1 or 2. 

Did scenes from the future come to you ? -- 0 out of 22 answered either 1 or 2. 

Did you feel separated from your body?  -- 16 out of 22 answered either 1 or 2. 

Did you seem to enter some other, unearthly world? -- 4 out of 22 answered either 1 or 2.

Did you seem to encounter a mystical being or presence, or hear an unidentifiable voice? -- 2 out of 22 answered either 1 or 2.

Did you see deceased or religious spirits? --0 out of 22 answered either 1 or 2.

Did you come to a border or point of no return? -- 0 out of 22 answered either 1 or 2.

But did these "either 1 or 2" answers tend more to be the relatively weak "1" answer or the much stronger "2" answer? We will never know, because Martial has failed to tell us. We may presume with high confidence that the answers tended much more to be the weaker 1 answers than the stronger 2 answers, because if Martial had got lots of the stronger 2 answers, she almost certainly would have published those answers (that being much stronger evidence of the effect she was trying to show). 

There is no excuse for the defect of this paper's failure to provide the exact numbers for the data and the paper's use of ambiguity shrouding what the exact answers were.  No robust evidence has provided here of the creation of near-death experiences by voluntary procedures designed to produce fainting.  The paper has failed to document any of its subjects having a near-death experience. 

All that the paper documents is a minor tendency of respondents to give answers  above 0 when asked some of the Greyson Scale questions that can be answered as 0, 1 or 2.  That minor tendency can credibly be explained as an effect in which subjects tended to give answers that might be pleasing to scientists who they knew were hoping to get people describe something a little bit like a near-death experience. 

When a study like this is done, it is vital that the researchers tell us exactly what the subjects were told about the experiment prior to the experiment being conducted.  We are told that the subjects were volunteers. Were the subjects told that the experiment would be an attempt to see whether people fainting would produce reports like those given in near-death experiences? Such information might have produced a magnet effect, in which the people agreeing to participate would be more likely to be those hoping to help discredit near-death experiences, by reporting something like near-death experience effects after fainting. Such information might have also produced an expectation effect in which the subjects thought the experimenters were hoping to get reports like those of near-death experiences.    But the paper co-authored by Charlotte Martial does not tell us this vitally important information about what the subjects were told about the experiment before it was conducted. Its supplemental information document has only a generic template for an informed consent document, rather than the actual informed consent document the subjects signed. 

In both of the papers discussed above, it is claimed that 7 on the Greyson Scale is a threshold for a near-death experience.  The paper "DMT Models the Near-Death Experience" claims, " A total score higher or equal to 7 is considered the threshold for a NDE (Greyson, 1983)."  The paper "EEG signature of near-death-like experiences during syncope-induced periods of unresponsiveness" makes a similar claim, repeatedly claiming that any score of 7 or higher on Greyson Scale qualifies an experience as "NDE-like."  But in his paper introducing the Greyson Scale, Bruce Greyson never said that a score of 7 or higher qualified an experience as a near-death experience. 

Instead, Greyson stated that the average Greyson Score for near-death experiences he studied was 15 out of a maximum of 32. He stated the following:

"The criterion sample of NDE reporters had a mean score of 15.01 on the NDE Scale [Greyson Scale] out of a total possible 32 points; i.e., they acknowledged the definitive presence of about half the scale items. The cut-off point on the NDE Scale for the determination of a NDE may vary with the purpose of making such a determination. A cut-off point 1 SD below the mean should include 84 per cent of all positive cases, assuming a normal distribution of scores of those with NDEs. This criterion would require a score of 7 or higher to establish the presence of a NDE; in the criterion sample, 62 subjects (83.8 per cent) had NDE Scale scores of 7 or higher."

This is not equivalent to saying that anything with a Greyson Scale of 7 or higher qualifies as a near-death experience. 

Looking at the questions in Greyson's original paper introducing the Greyson Scale, it is easy to see how someone can give answers getting a score of 7, when describing experiences that are not at all like near-death experiences that include out-of-body experiences. Here are some examples:

Example 1:  Someone fires a bullet at you, and misses. You give an answer of 2 to Question 1 (asked about whether time seemed to speed up), because the experience was real quick, so you thought "Everything seemed to be happening all at once." You give an answer of 1 to Question 2, because this experience caused you to think faster than normal, with thoughts rapidly occurring. You give an answer of 2 to Question 5, because you experienced "incredible peace" after realizing the bullet missed you. You give an answer of 2 to Question 6, because you experienced "incredible joy" after realizing the bullet missed you.  So you have now already reached 7 on the Greyson Scale, even though the experience had no resemblance to near-death experiences as they are commonly reported. 

Example 2:  You take some drug that seems to give you a "rush" like the exhilaration reported when people inject heroin. You give an answer of 2 to Question 1, answering  "Everything seemed to be happening all at once,"  because that's an ambiguous phrase that someone might easily choose to describe a heroin rush. You give an answer of 1 to Question 2, because this experience caused you to think faster than normal, with thoughts rapidly occurring. You give an answer of 2 to Question 5, because you experienced "incredible peace" after getting the super-pleasant feeling of the heroin. You give an answer of 2 to Question 6, because you experienced "incredible joy" after realizing that you were going to be feeling super-good for quite a while.  So you have now already reached 7 on the Greyson Scale, even though the experience had no resemblance to near-death experiences as they are commonly reported. 

These examples help show that it is incorrect for scientific studies to be reporting Greyson Scale scores of 7 as evidence for near-death experiences.  Going forward,  we should follow these rules of evaluation when evaluating studies trying to experimentally reproduce near-death experiences:

(1) No such study should be taken seriously unless the authors report fully on exactly what the subjects were told about the experiment before it occurred. 

(2) The validity of any such study should be doubted if the subjects were told (or allowed to learn) that the study was some study attempting to experimentally produce near-death experiences, particularly if the subjects were largely neuroscience department students. Under such a case there is  too high a chance that the study will attract materialist volunteers eager to discredit near-death experiences (a thorn in the side of materialists) by reporting experiences sounding like near-death experiences, and too high a chance that subjects will report something like near-death experiences, to try to please researchers eager to get such reports. 

(3) No such study should be taken seriously unless it includes transcripts of interviews with the subjects, in which they described what they experienced after the experimental intervention designed to mimic a near-death experience. Such transcripts are vital to help determine whether a subject actually had an experience matching the answers he may have given when asked questions corresponding to the Greyson Scale. 

(4) Subjects should not be regarded as having had a near-death experience unless they either supply a narrative matching the typical narratives of near-death experiences, or give answers resulting in a score of at least 15 on the Greyson Scale, the average score of those reporting near-death experiences. There are too many ways for experiences unlike near-death experiences to result in Greyson Scale scores of merely 7.  

There is no substance in any neuroscientist attempt to explain out-of-body experiences or near-death experiences.  The attempts that have been made by neuroscientists to explain such phenomena have been largely characterized by dishonesty, misstatements, vacuous hand-waving and irrelevance. For a critical discussion of some of the attempts that have been made, see my post "There Is No Evidence of a Neural Explanation for Out-of-Body Experiences" which you can read here, and my post "Misleading Claims in Attempts to Naturally Explain Near-Death Experiences and Out-of-Body Experiences," which you can read here, and also my post "The Guardian's Misleading Story on Near-Death Experiences" which you can read here. For a discussion of 11 features of out-of-body experiences, none of which neuroscientists can explain, read my post here. 

Near-death experiences and out-of-body experiences provide some of the strongest evidence against claims that brains make minds and claims that brains store memories.  When such experiences occur during cardiac arrest when the brain shuts down electrically and flatlines, as they often do, such experiences (resulting in the most vivid and unforgettable of memories) demonstrate that memories can be created independently of brain action. 

Schematic depiction of an erring researcher of tomorrow

A better paper by Martial on this topic is the paper "

The Near-Death Experience Content (NDE-C) scale: Development and psychometric validation" where we get some good data from a survey of 403 people who claimed to have had a near-death experience. She has a scale mentioning features of near-death experiences, in which people can give a number between 0 and 4, with 0 meaning "not at all, none," 1 meaning "slightly," 2 meaning "moderately," 3 meaning "strongly" and 4 meaning "extremely, more than any other time in my life, and stronger than 3." The percentages giving the highest answer (4) are striking:

• 62% give the "extremely" answer (4) for "you had the impression of being outside of, or separated from your own body."
• 58% give the "extremely" answer (4) for "you had the sensation of leaving the earthly world or of entering a new dimension and/or environment."
• 56% give the "extremely" answer (4) for "you saw or felt surrounded by a bright light without any determined material origin."
• 35% give the "extremely" answer (4) for "your thoughts speeded up."

Three of these four percentages are higher than those reported by Greyson in a survey of 72 people. 

Appendix: Removal of one of the brain's temporal lobes to treat epilepsy was done thousands of times a year in the decades before the year 2003, and also in the past two decades. Reports of severe memory problems following removal of the temporal lobe are actually rare.  A 2003 scientific paper tells us how rare how such cases are:

"Davies and Weeks (1993) did report one case of postoperative amnesia in a series of 58 cases of unilateral temporal lobectomy, whereas Walczak et al. (1990) found one case of marked deterioration in memory from a preoperative normal state in their series of 100 patients who underwent such surgery. Rausch and Langfitt (1992) estimated that, on the basis of their series, 'the prevalence of patients at risk for postoperative amnesia who otherwise met criteria for surgery fell between one and four out of 218’ (p. 508), and Jones‐Gotman et al. (1993) noted that 'the base‐rate of post‐resection amnesia, were all patients operated on without prior screening with the amobarbital procedure, may be less than 1%, (p. 447).' "

The authors of the 2003 paper state, "We were able to locate nine definite cases of amnesia following unilateral temporal lobe surgery in the English‐language literature." This is not very worrying, given that (1) many thousands of operations of this type were done before the year 2003; (2) doctors or scientists often loosely use the term "amnesia" for any of a large variety of memory performance problems, and typically use such a term for cases that are something other than a severe loss of learned or episodic memories; (3) there are many reasons why a person may have memory problems, and a few people having memory problem after a particular operation does not show the operation caused such a memory problem. 

In fact, in Table 3 of the paper we are given the details of the impairments of these nine cases of claimed amnesia; and none of them sound like a case of loss of knowledge or episodic memories (with the possible exception of case 5, which is not well-described). We hear about what seem like rather minor memory performance shortfalls.  A 2009 study carefully testing "before and after" memory results for 82 patients who had surgery for temporal lobe epilepsy tells us this: "The main finding of this study is that, at variance from the picture emerging from short-term follow-up studies, longer-term memory outcome after TLE [temporal lobe epilepsy] surgery seems to be good, as after 2 years memory performance was equal to or better than baseline [before surgery] in most patients." A review of 911 surgical operations for epilepsy (looking for bad effects) mentions no case of amnesia or memory loss or memory deterioration. 

There is no robust evidence that surgical treatment for temporal lobe epilepsy causes loss of memories.

Postscript: A noteworthy new study "Out-of-body experiences: interpretations through the eyes of those who live them" gives us two cases similar to what I discussed above when I said that "very many accounts of near-death experiences have discussed people describing details of the real world (including real events) during out-of-body experiences, events and details they should not have been able to have known about during some state of what looked like unconsciousness or cardiac arrest occurring during their near-death experiences." We read this:

"Participant 5 described an out-of-body experience where she visited the hospital to see her aunt in the Intensive Care Unit (ICU). The following day, upon visiting the hospital in reality, she was deeply surprised to find that the hallway, the door, and the ICU where her aunt was located were exactly as she had seen during the OBE. Participant 10 reported that during her OBE, she visited a village in Scotland. As she flew in, she observed a bridge and a specific landscape, and upon 'landing' in the village, she noticed the village's name. Later, she confirmed on a map that both the river and the village existed."

The authors incorrectly state this:

"Given the complexity and subjective nature of OBEs, analyzing and explaining them within the scientific paradigm is an extremely complex task. It is not surprising, therefore, that the first publications on this phenomenon appeared in parapsychology journals (Alvarado, 1982; De Foe et al., 2013; Irwin, 2000)." 

To the contrary, out-of-body experiences were thoroughly documented in many publications much earlier than 1982, such as these books of Robert Crookall published around 1964 to 1970:

• Out-of-the-Body Experiences by Robert Crookall;
• More Astral Projections by the same author, containing some fascinating cases I discuss here;
• What Happens When You Die by the same author.

And out-of-body experiences were well-described in the 1968 book Out-of-the-Body Experiences by Celia Green, and also well-described in the 1975 best-selling book Life After Life written by Raymond Moody. Newspaper accounts of out-of-body experiences appeared in the early 20th century, as I document in my post here.