The puzzle of near-death experiences
Just a month or so ago, the results of an international study (led by Dr. Sam Parnia at the State University of New York) of more than 2000 cardiac arrest patients were published. This found that 40% reported some form of awareness during the time when they were clinically dead, when their hearts had stopped beating and their brains had shut down. But how can we be sure that the awareness they reported actually stemmed from the period when they were “dead”? you might ask. Perhaps it was just a kind of hallucination which actually took place just before their brains shut down, or just when they were becoming active again.
However, as was the case with my colleague John, some patients reported a sensation of leaving their bodies and observing their own operations from above. They were able to describe actual events during the procedure – such as the actions of the nurses, or the instruments used by their surgeons, and the sounds of machines – which were later verified. (One man accurately described the appearance of the doctors who attended to him, and also the automated external defibrillator that restarted his heart).
Of course, there have been many other studies of NDEs, with similar findings. Researchers have found that there is a “core” near-death experience which is had by the majority of those who experience a continuation of consciousness. It begins with a feeling of separation from the body (out of body experience), followed by a journey through a dark passage towards a place of light. There is a feeling of serenity and intense well-being, a sense of calmness and wholeness, which is often so pleasant that some people are reluctant to return to their bodies, and even feel disappointed when they regain consciousness. Often people meet deceased relatives or beings of light, and in a smaller proportion of cases, there is a “life-review”, in which the significant events of a person’s life are replayed.
These experiences are so common amongst people who are resuscitated that they require explanation. Once a person’s heart has stopped beating, the brain shuts down within 20-30 seconds. So how can a person continue to be conscious during this period?
Since the idea that consciousness could continue without brain activity appears highly unlikely to many people, other explanations have been put forward. First of all, can we really rely on the reports of people who believed they saw their own operations from above and described details about them? Perhaps they were simply constructing an image of what they expected from the operation, including the doctors, nurses, instruments and procedure.
And in any case, can we really be sure that the brain is completely “shut down” in these periods? Even if it doesn’t show any sign of activity shortly after the person’s heart stops beating, does that mean there is no activity at all? Perhaps there is brain activity at a very low level which is difficult to detect.
However, even if this is plausible, there would still be the problem of explaining how a very low degree of brain activity (so low that it is undetectable) could give rise to an experience of such complexity and intensity. In near-death experiences, people often report feeling much more alert than normal, with a very clear and intense form of awareness. It is difficult to see how a very low level of brain activity could generate this. If anything, there would surely be a form of consciousness which was much more vague, confused and dim.
Perhaps the best way of explaining NDEs in material terms is – as touched on briefly above – to see them as unusual experiences which occur shortly before the brain becomes inactive. Perhaps they are simply a kind of hallucination generated by a dying brain. For example, It has been suggested that cerebral anoxia – a lack of oxygen to brain tissue – causes many of the characteristics of NDEs. It results “cortical disinhibition” and intense, uncontrolled brain activity. The vision of tunnels and lights can be linked to disinhibition in the brain’s visual cortex. At the same time, the intense sense of well-being could be caused by the release of endorphins.
However, there are also problems with these explanations. You would expect intense, uncontrolled brain activity to result in crazy, chaotic experiences, but NDEs are usually very serene and well integrated experiences – certainly not what one would associate with ‘disinhibition’ and over-stimulation. You would also expect uncontrolled brain activity to result in a very wide range of different experiences, as varied and different as dreams. However, as we have seen, the majority of people who report this continuation of consciousness report the same “core” experience (according to another researcher, Pim van Lommel, 66% of NDEs included the core characteristics.) An additional (although not as significant) point is that, subjectively, people feel that, far from being illusory or hallucinatory, NDEs are much more intensely real than normal consciousness. They carry an intense sense of clarity and revelation which is very different to most hallucinatory experiences.
Another suggestion is that NDEs are caused by the release of large amounts of DMT in the brain close to the point of death. The basis of this explanation is the similarity of some DMT experiences (when it is taken as a drug) to NDEs. However, in actual fact, studies have shown that only a small percentage of DMT experiences have any strong similarity of NDEs. If it was the source of the experience, one would expect a stronger relationship.
As you’ve probably guessed, I don’t think NDEs can be satisfactorily explained in material terms. I don’t even think they need to be explained in material terms. If you believe that consciousness is produced by the brain, then you also have to believe that consciousness ends when the brain shuts down – and therefore you have to try to explain NDEs in material terms. But the idea that consciousness is produced by the brain is really little more than assumption, without any clear evidence. It is also very problematic. Despite many years of intensive research, scientists still haven’t come up with any viable explanations of how the brain could produce consciousness, or even about which parts of the brain (or what type of brain activity) might be related to consciousness. Some philosophers believe that it’s not actually possible to reduce the richness of human experience down to the activity of brain cells, and have suggested that we should look elsewhere for an explanation. (One alternative – suggested by David Chalmers and others – is that consciousness may be a fundamental force of the universe, which potentially exists everywhere and in everything. The function of the brain may not be to produce consciousness, but to receive it, like a radio aerial.) Consciousness is obviously closely associated with the brain, but not necessarily produced by it. In that sense, it is at least conceivable that it could continue in some form (at least for a short period of time) without brain activity.
Do NDEs suggest that there is life after death? I personally wouldn’t go that far. I would only say that they suggest that there may be an initial continuation of consciousness after physical death. We obviously can’t say how long this continues for. Perhaps the really important thing about NDEs is that they show how limited our normal perspective of reality is, and that there are some phenomena which are beyond our understanding, and beyond our normal awareness. There is a tendency for us to believe that we perceive the world as it is, and that we are capable of coming to a clear understanding of how the universe operates. Certainly many materialists believe that they possess a sound explanatory framework to make sense of human life and the world we live in. However, this is premature and arrogant. Like any other animal, we have a limited awareness of reality and a limited intellect. The world is much more complex than we can sense, and most likely full of phenomena which we are not aware of, or which we might be aware of but cannot explain or understand. Near-death experiences are so significant because they remind of this.
Steve Taylor teaches mainly on the Psychology and Society course, and is the Module Leader for Consciousness Studies and Positive Psychology. He is a widely published and well known author of books on psychology and self-development.