Skeptical accounts of near-death experiences

The dying brain. Susan Blackmore argued that the main features follow from a brain losing oxygen. Disinhibition in the visual cortex produces a growing central light, experienced as a tunnel. The brain's model of the body breaks down, producing a sense of floating outside it. Endorphins produce peace.^[1]

REM intrusion. Kevin Nelson and colleagues found that people who had near-death experiences were more likely than others to have a history of REM sleep intruding into waking, as in sleep paralysis. They proposed that the same mechanism, triggered by crisis, produces the experience.^[2]

Neurochemistry. The anesthetic ketamine and the psychedelic DMT can each produce states that resemble near-death experiences. A comparison of thousands of written drug reports with near-death accounts found ketamine experiences the most similar.^[3][4]

A surge of activity. Experiments in rats found a brief burst of highly organized brain activity in the seconds after cardiac arrest.^[5] If the same happens in humans, the dying brain may be briefly more active, not less.

Temporal lobe and expectation. Stimulation of parts of the temporal and parietal lobes can produce out-of-body sensations. Culture supplies the imagery, and memory may fill in details afterward.

Dean Mobbs and Caroline Watt summarized the case in a paper titled "There is nothing paranormal about near-death experiences."^[6]

Researchers such as Bruce Greyson and Pim van Lommel accept that the brain is involved and dispute that the proposals are sufficient.^[7]

• Clarity. Low oxygen and most drugs produce confusion and fragmentary memory. Near-death experiences are reported as lucid and are remembered in detail for decades.
• Incidence. If oxygen loss were the cause, nearly all cardiac arrest survivors should report one. About one in ten to one in five do.
• Partial resemblance. Each proposal reproduces some features. None reproduces the full pattern together with the lasting change in values.
• Timing. A flat brain recording during cardiac arrest is hard to reconcile with complex experience, though it is uncertain when during the event the experience occurs.

Three points are fair to both sides.

1. No brain-based account has been shown to explain near-death experiences in full. The proposals are plausible mechanisms, not demonstrated causes.
2. The absence of a complete explanation is not evidence for survival of death. Gaps in current knowledge have often been filled later.
3. The question that would decide the matter is whether people perceive things during clinical death that they could not have known. Controlled attempts to show this have not yet succeeded. See Verification and falsifiability.

The framework reads near-death experiences as glimpses of consciousness apart from the body. That reading is permitted by the evidence and is not required by it. If a complete brain-based explanation is established, the framework will have lost its strongest empirical support.

1. Blackmore, S. (1993). Dying to live: Near-death experiences. Prometheus Books.
2. Nelson, K. R., Mattingly, M., Lee, S. A., & Schmitt, F. A. (2006). Does the arousal system contribute to near death experience? Neurology, 66(7), 1003-1009.
3. Timmermann, C., Roseman, L., Williams, L., Erritzoe, D., Martial, C., Cassol, H., et al. (2018). DMT models the near-death experience. Frontiers in Psychology, 9, 1424.
4. Martial, C., Cassol, H., Charland-Verville, V., Pallavicini, C., Sanz, C., Zamberlan, F., et al. (2019). Neurochemical models of near-death experiences: A large-scale study based on the semantic similarity of written reports. Consciousness and Cognition, 69, 52-69.
5. Borjigin, J., Lee, U., Liu, T., Pal, D., Huff, S., Klarr, D., et al. (2013). Surge of neurophysiological coherence and connectivity in the dying brain. Proceedings of the National Academy of Sciences, 110(35), 14432-14437.
6. Mobbs, D., & Watt, C. (2011). There is nothing paranormal about near-death experiences: How neuroscience can explain seeing bright lights, meeting the dead, or being convinced you are one of them. Trends in Cognitive Sciences, 15(10), 447-449.
7. Greyson, B., Kelly, E. W., & Kelly, E. F. (2009). Explanatory models for near-death experiences. In J. M. Holden, B. Greyson, & D. James (Eds.), The handbook of near-death experiences: Thirty years of investigation (pp. 213-234). Praeger.