A major problem in studying the Intuitive System is that we don't have conscious access to the things that go on in this layer of the mind. When a research participant reports what he or she is thinking about, we have argued, they are generally providing the output of their Narrative System. Narratives are filtered through language, and incorporate beliefs, intentions, and cognitive maps of the world that may not accurately reflect what's truly happening at the immediate level of perception, experience, and behavior -- a set of processes that we call collectively the Intuitive System. Indeed, as I described in one of last year's blog posts, the very structure of the brain systems involved in creating narratives tends toward abstraction, generalization, and summarizing, all of which necessarily obscure details about a person's immediate experience. The primacy of narratives in every commonly used measure of people's experiences is a significant methodological challenge for Two Minds Theory, which proposes that the outputs of the Narrative System come second, after the Intuitive System has already produced behavior. How can we understand the Intuitive System outside of people's narratives?
We have already proposed two solutions to this problem that are suitable for everyday research applications: the use of sensor data and the use of biological measures. Sensors can provide data on behaviors like activity or sleep, or on environmental factors like light or noise. Biological measures can describe body processes that go on outside of consciousness, and are particularly useful when used in everyday life to describe biomarkers that change over time -- for instance, heart rate variability tracking or continuous blood glucose monitoring. In this post, I will argue for a very different and non-routine source of data about the Intuitive System: the near-death experience.
Near-death experiences (NDE) are well documented in the medical and psychological literature. NDE have been reported across cultures and throughout history, but are becoming more common because modern resuscitation techniques and technologies have allowed more people to give a report after medical experiences that they would not have survived a few decades ago. In one prospective study, about 11% of people who experienced cardiac arrest also had an NDE. Although every person's experience is different and not all features are present for all experiencers, NDE have certain commonalities that do not seem to be related to the medical features of the case, the person's demographic characteristics, or the person's prior religious beliefs (or lack thereof). These include:
- A bright light or encounter with a "being of light"
- A heightened sense of awareness, meaning, or understanding; this is sometimes expressed as being in a place where all knowledge exists
- An encounter with spiritual beings who may be seen as religious figures (e.g., angels), may be recognized as deceased relatives, or may not be recognized
- A feeling that the flow of time changed in some way, becoming faster or slower
- A feeling of harmony, peace, pleasantness, or joy*
- Extra-sensory abilities, such as seeing one's own body from above, hearing things in a distant location, or ability to move one's point of perception by thought alone
- A sense of a border, a gateway to another domain, or a "point of no return" where a decision is made to go back to the physical world
* Although the vast majority of NDE are described as broader, richer, deeper, or more satisfying than ordinary life, a small number of people report frightening NDE. These occasionally involve hellish imagery, or a sense of nonexistence or void. Certain NDE seem to involve exactly the same experiences as the more common positive NDE, except that the person interprets them as terrifying. Dr. Alexander's detailed report (see below) includes both "underworld" and "heaven" imagery.
Although NDE are not well understood, some common explanations for why they occur involve cerebral hypoxia, experiences of losing or regaining consciousness, or psychological compensation -- essentially a made-up story to deflect a fear of death. All of these explanations seem implausible. Some of the evidence comes from prospective studies of people with cardiac arrest. NDE occurrence or non-occurrence is not correlated with the duration of cardiac arrest or unconsciousness, and may in fact be inversely related to oxygen levels in the brain during a heart attack which runs counter to the hypoxia theory. Fear of death before the heart attack is not associated with greater likelihood of having a NDE.
Furthermore, a recent study on end-of-life dreams and visions among nursing home residents found a high prevalence of imagery similar to those in the classic cardiac-arrest NDE: meeting living or deceased family members, religious figures, a sense of traveling somewhere, and a sense of meaning that was especially based on past meaningful experiences. Cancer, delirium, and pain were the most common problems in this sample, and only 15% had a diagnosis of heart failure. The researchers also found that end-of-life dreams and visions became more frequent as the moment of death approached, and that positive interactions with deceased loved ones in particular became more frequent. These findings are not readily attributable to hypoxia, as only 17% of participants had shortness of breath.
In some celebrated instances such as the 1991 case of singer Pam Reynolds, or the report by neurosurgeon Dr. Eben Alexander in his 2012 book Proof of Heaven, the NDE could be more accurately described as a "death experience" because it was accompanied by medically-verified cessation of all higher brain functions, which is our best-available definition of clinical death. In Reynolds' case, all of the blood in her head was drained in order to repair an aneurysm, while her core body temperature was lowered to 60 degrees to ready her for surgery. In Alexander's case, the shutdown of brain functions happened more organically over several days due to bacterial meningitis. In both cases medical instruments showed a complete absence of higher brain activity, and in Alexander's there weren't even any automatic neural firings from the brain stem. These patients' breathing and heartbeat were sustained through completely mechanical means without any accompanying brain activity, facts that were verified through continuous monitoring by sophisticated medical technology. Each of these patients then experienced an amazing recovery, and reported having experienced a richly detailed NDE during the time that they were clinically brain-dead.
In general, then, the simplest explanation for NDE seems to be that they are veridical reports of people's actual experiences rather than physiological glitches or wishful thinking. What those experiences actually mean is of course open to interpretation. From a TMT perspective, how can NDE tell us anything about the functioning of brain systems, if they occur when people's brains aren't working? Even NDE skeptics agree that the higher brain areas shut down soonest -- the ones connected to language and reason, including the prefrontal cortex, or what we have referred to as the Narrative System. The body automatically preserves brain function from the outside inward, saving until last the reptile-brain functions in the medulla oblongata that regulate breathing and circulation. So when people report an NDE, they are expressing in words what it was like to experience a brain that was temporarily without the capacity for words. In some rare cases like Reynolds's or Alexander's even the Intuitive System may be shut down, but in simpler cases of cardiac arrest the lower-brain systems are likely still at least partly active. So the NDE under the most stringent assumptions takes us a person's experience down into the Intuitive System (under more expansive assumptions it leads us below and beyond the Intuitive System into a purely spiritual realm).
What's truly remarkable about NDE is that while people are experiencing restricted brain function, their subjective experience is almost always one of expanded awareness (a paradox noted by philosopher Bernardo Kastrup). In fact, people have reported similarly expanded consciousness during a variety of other life-threatening mental states such as psychedelic drug intoxication, suffocation, or g-force induced blackouts among fighter jet pilots. For NDE survivors, the experience understandably can be hard to put into words. Some common themes, however, include feeling more connected and at peace with the universe, as well as retaining at least a mildly enhanced sense of awareness in daily life. These experiences reinforce some of what we know already about the Intuitive System: that it arrives at decisions outside of language, that it multi-tasks effectively, and that it is in some ways larger or more expansive than the "sparseness" of conscious thought.
What the NDE adds to our understanding is an idea that the Intuitive System perceives connections to the world and other people that may be invisible to our conscious minds. The positive sensations and feeling of knowledge associated with NDE also highlight the unspoken wisdom of the Intuitive System, a set of processes most often denigrated for its tendency toward heuristics, biases, and snap judgments. Rather than being deficient compared to conscious thought, the Intuitive System may be wise in ways that we don't appreciate. The Intuitive System is located in brain areas that evolved earlier than the Narrative System; the overwhelmingly positive and expansive features of most NDE suggest that this system may convey a type of knowledge and experience that we have largely forgotten in our over-reliance on conscious thought.
Furthermore, a recent study on end-of-life dreams and visions among nursing home residents found a high prevalence of imagery similar to those in the classic cardiac-arrest NDE: meeting living or deceased family members, religious figures, a sense of traveling somewhere, and a sense of meaning that was especially based on past meaningful experiences. Cancer, delirium, and pain were the most common problems in this sample, and only 15% had a diagnosis of heart failure. The researchers also found that end-of-life dreams and visions became more frequent as the moment of death approached, and that positive interactions with deceased loved ones in particular became more frequent. These findings are not readily attributable to hypoxia, as only 17% of participants had shortness of breath.
In some celebrated instances such as the 1991 case of singer Pam Reynolds, or the report by neurosurgeon Dr. Eben Alexander in his 2012 book Proof of Heaven, the NDE could be more accurately described as a "death experience" because it was accompanied by medically-verified cessation of all higher brain functions, which is our best-available definition of clinical death. In Reynolds' case, all of the blood in her head was drained in order to repair an aneurysm, while her core body temperature was lowered to 60 degrees to ready her for surgery. In Alexander's case, the shutdown of brain functions happened more organically over several days due to bacterial meningitis. In both cases medical instruments showed a complete absence of higher brain activity, and in Alexander's there weren't even any automatic neural firings from the brain stem. These patients' breathing and heartbeat were sustained through completely mechanical means without any accompanying brain activity, facts that were verified through continuous monitoring by sophisticated medical technology. Each of these patients then experienced an amazing recovery, and reported having experienced a richly detailed NDE during the time that they were clinically brain-dead.
In general, then, the simplest explanation for NDE seems to be that they are veridical reports of people's actual experiences rather than physiological glitches or wishful thinking. What those experiences actually mean is of course open to interpretation. From a TMT perspective, how can NDE tell us anything about the functioning of brain systems, if they occur when people's brains aren't working? Even NDE skeptics agree that the higher brain areas shut down soonest -- the ones connected to language and reason, including the prefrontal cortex, or what we have referred to as the Narrative System. The body automatically preserves brain function from the outside inward, saving until last the reptile-brain functions in the medulla oblongata that regulate breathing and circulation. So when people report an NDE, they are expressing in words what it was like to experience a brain that was temporarily without the capacity for words. In some rare cases like Reynolds's or Alexander's even the Intuitive System may be shut down, but in simpler cases of cardiac arrest the lower-brain systems are likely still at least partly active. So the NDE under the most stringent assumptions takes us a person's experience down into the Intuitive System (under more expansive assumptions it leads us below and beyond the Intuitive System into a purely spiritual realm).
What's truly remarkable about NDE is that while people are experiencing restricted brain function, their subjective experience is almost always one of expanded awareness (a paradox noted by philosopher Bernardo Kastrup). In fact, people have reported similarly expanded consciousness during a variety of other life-threatening mental states such as psychedelic drug intoxication, suffocation, or g-force induced blackouts among fighter jet pilots. For NDE survivors, the experience understandably can be hard to put into words. Some common themes, however, include feeling more connected and at peace with the universe, as well as retaining at least a mildly enhanced sense of awareness in daily life. These experiences reinforce some of what we know already about the Intuitive System: that it arrives at decisions outside of language, that it multi-tasks effectively, and that it is in some ways larger or more expansive than the "sparseness" of conscious thought.
What the NDE adds to our understanding is an idea that the Intuitive System perceives connections to the world and other people that may be invisible to our conscious minds. The positive sensations and feeling of knowledge associated with NDE also highlight the unspoken wisdom of the Intuitive System, a set of processes most often denigrated for its tendency toward heuristics, biases, and snap judgments. Rather than being deficient compared to conscious thought, the Intuitive System may be wise in ways that we don't appreciate. The Intuitive System is located in brain areas that evolved earlier than the Narrative System; the overwhelmingly positive and expansive features of most NDE suggest that this system may convey a type of knowledge and experience that we have largely forgotten in our over-reliance on conscious thought.
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