Out-of-Body Experiences

While extracorporeal existence of an individual ‘soul’ is generally held to be a spiritual proposition, such strong dualism is arguably a scientific hypothesis due to witness reports of out-of-body experiences (OBEs) involving observations of the physical world from an extracorporeal location. Such OBE reports containing information about alleged states of affairs in the physical world are either true or false and are thereby amenable to scientific-hypothesis testing. Herein I examine the current state of scientific investigation into the nature of OBEs and consider the implications for strong dualist, physicalist, and other explanatory models.

Nature and Scope of OBEs

During an OBE an observer appears to occupy a location outside her or his physical body, often seeing it from an external point of view. Occultists hold that the vehicle of OBEs is the astral body. When not projected outward, the astral body is said to occupy the same space as the physical body, extending outward several inches to form the ‘aura’. [1] OBEs have been reported across cultures and throughout human history. Given such universal existence it seems plausible that, as Thomas Metzinger argues, OBEs may have been the fundamental nexus of belief in a ‘soul’, which then called for explanatory ‘spiritual world’ models that then became religions. [2] In modern times, scientists generally see OBEs as a manifestation of lucid dreaming -- a state of self-awareness during a dream. Lucid dreaming is a central theme of the contemporary cult movie Waking Life. [3] For the observer having an OBE, the prima facie meaning of the experience is that the ‘self’ or ‘soul’ has extracorporeal existence. OBEs therefore constitute prima facie evidence of extracorporeal existence.

Testability of the Strong Dualist Model

While OBEs constitute prima facie evidence for strong dualism, scientific evidence generally derives from data obtained from repeatable experiments. To appreciate the important distinction between prima facie and scientific evidence, consider an optical illusion involving two lines apparently of unequal lengths.

Line AB appears to be shorter than line BC, yet both lines are the same length.
Image source: http://coolopticalillusions.com/optical_illusions_images_2/longer_line.htm

The appearance that lines AB and BC are unequal constitutes prima facie evidence of inequality. But scientific evidence comes from testing that prima facie evidence by measuring the lines. Applying the ‘ruler test’ to the proposition “AB is shorter than BC” soundly falsifies that perception-representative proposition. The ‘ruler test’ constitutes scientific testing yielding replicable scientific evidence that proves, contrary to the prima facie evidence, that: “It is not the case that AB is shorter than BC.”

To the extent that OBE reports are propositions about states of affairs involving the physical world -- such as, “I was in a ‘spirit body’ looking down on my home” -- they are either true or false and as such are amenable to scientific testing. But what tests might we conduct? Reliable acquisition of accurate remote data in conjunction with OBEs would constitute scientific evidence (though not proof) that the claimed state of affairs may be taking place. It would not constitute proof since another explanation could be that such data acquisition derives from ESP in conjunction with an illusion of dislocation. But in either case, if someone could reliably access remote data in conjunction with OBEs, the strong-dualist model would have the support of scientific evidence.

Other tests that could be conducted to acquire scientific evidence for the strong-dualist OBE model would be verifiable (i.e., unambiguous and repeatable) detection of some kind of physical disturbance associated with the reported location of a projected ‘spirit body’. A few isolated studies have been conducted to look for such evidence.

Scientific Evidence for the Strong Dualist Model

Scientific testing of the extracorporeal model is remarkably scarce. A few studies were conducted by Charles Tart of the University of California at Davis. In one case, during an OBE a subject presumably successfully read the random number 25132 that had been placed in a position only accessible from a position someone floating just below the ceiling would be in. Tart says the odds of guessing the number are 1 in 100,000, and he is confident that the subject did not cheat, though she was not continuously observed. That is the only remarkable result out of six small OBE tests Tart has conducted. [4]

Stanley Krippner cites an OBE study that also tested the ability to acquire remote data during an OBE. While the results were not statistically significant, Krippner feels they are “at least provocative given the small number of nights in this pilot study.” [5] Two studies cited by Karlis Osis purport evidence of a projected ‘spirit body’. In the first, a cat is reported to have shown signs of awareness of the presence of its owner’s projected ‘spirit body’. In the second, “strain gauge measures” purportedly showed signs of the presence of a ‘spirit body’ allegedly projected to the measure location. [6]

Those studies tested OBE claims in the ways suggested -- testing for remote-data access or ‘spirit body’ detection. However, the obscurity, lack of recognition by the scientific community, general weakness of results, informality, and lack of replication of those studies renders them of questionable meaning and value. As Carl Sagan says, extraordinary claims require extraordinary evidence. Yet the question is whether the extraordinary strong-dualist model has any supporting scientific evidence. Certainly strong dualism lacks extraordinary evidence. However, what’s most noteworthy is that this lack has more to do with an overall dearth of OBE-claim testing rather than there being research explicitly falsifying extracorporeal existence. Strong dualism -- i.e., the belief that each person has an extracorporeal and postmortem ‘spirit body’ -- has possibly been one of the most widely held beliefs throughout human history and to this day. Given that, it’s odd that so little research has tested witnesses claiming detectable instances of strong dualism, i.e., OBEs, along the lines of scientific testing mentioned above.

Scientific Evidence for the Physicalist Model

The physicalist explanation sees OBEs as a manifestation, or symptom, of aberrant processing of perceptual data within a brain. So claims about the world arising from an OBE are assumed to not reflect any state of affairs outside an OBE-reporting brain. Scientific research supporting the physicalist model has been steadily growing. In 1963, Penfield and Perot demonstrated that mild electrical stimulation of exposed brain regions induced auditory and visual hallucinations in subjects, which demonstrated the brain’s ability to manufacture representations of apparent yet unreal physical states of affairs. [7]

Then in 2002 Blanke et al found that electrical stimulation of a specific exposed brain region in a patient repeatedly produced OBEs in which the patient reported floating above and looking down on her own body, exactly matching traditional OBE reports. Stimulation of a nearby region produced false perceptions by the patient that her body was moving in specific ways when it was in fact motionless. Blanke et al concluded: “These observations indicate that OBEs and complex somatosensory illusions can be artificially induced by electrical stimulation of the cortex.” [8]

Then Frank Tong noted a similarity between Blanke’s patient and one of Penfield’s patients who, back in 1941, reported “floating away” and said, “I have a queer sensation as if I am not here.” Tong observes that in both cases “Both sets of stimulation sites encompassed the right temporal-parietal region posterior to the post-central gyrus, close to multisensory areas implicated in vestibular processing.” [9] Vestibular processing involves processing data related to the position of one’s body in its spatial environment. Clearly, disruptions in vestibular processing would be a predictable neurological basis for OBEs since they involve anomalous bodily perceptions.

More recently, Blanke and Arzy published a collection of reports from 10 subjects who had OBEs concurrent with right temporal and/or parietal lobe dysfunction, which encompasses the temporo-parietal junction (TPJ) already implicated in OBEs. [10] And it seems the TPJ is also where the brain models estimated points of view and thoughts of other minds. [11] [12] Also, positive schizotypal subjects with daily aberrant bodily perception given TPJ-processing tests demonstrate impaired TPJ processing. [13] Schizophrenia-spectrum disorders commonly involve confusion about self-agency, boundaries of self and other, and body perception likely to be associated with TPJ activity. Moreover, it has also been found that those reporting OBEs tend to have higher positive schizotypy scores than those who never had an OBE. [13] Taken together, the emerging evidence suggests that a broad spectrum of aberrant perceptions involving body position including OBEs may all have their origins in aberrant TPJ activity.

Other Models

The research just reviewed is problematic for the strong-dualist model because it implies that the nexus of OBE activation resides in the brain. To see the problem let’s consider another model. Suppose that you have a ‘spirit body’ that is activated by way of your brain. Just as your brain signals your arm to reach out for an apple, suppose your brain can signal your ‘spirit body’ to extend out and view the world from an otherwise remote location. But then your ‘spirit body’ is not anything like the ‘soul’, instead it’s just another limb, an appendage, a mere tool that the brain can use to probe the world.

That example introduces an alternative extracorporeal model that, unlike strong dualism, may be compatible with the scientific evidence. In this model, brain activities linked to OBEs occur in brain regions that direct the activities of some kind of information-gathering extension of the physical body. This extension might be a continuous projection from the body or a detachable subtle body. If OBE claims are true, it stands to reason that the brain would have regions via which it can activate such projection. So perhaps all the research showing a correlation of OBEs to specific brain activities is simply a progressive articulation of parts of a real mechanism of ‘sensory projection’. I doubt that’s the case, but of course we don’t know everything and that model probably can’t be ruled out at this time due in large to the lack of research explicitly testing the view that OBEs constitute some extracorporeal projection.

Another highly speculative alternative model holds that no ‘spirit body’ exists and all OBEs are activated and contained within the brain. However, in this model the brain accesses remote data by means locating ‘self’ in corresponding remote locations in its model of the world. This model assumes passive ESP that is somehow activated by modification to the location of ‘self’ within the brain’s own model of the world. Both this and the previous model could be tested by success or failure of remote-data access. The previous model could also be tested by way of success or failure in detecting some kind of ‘spirit body’ or subtle projection. However, lacking such testing and successful results, I see no reason to invest any degree of belief in these two other models.

Conclusion

The evidence we’ve observed shows that both exogenous (in the case of open-brain electrical stimulation) and endogenous (in the case of brain disorder) activation of the temporo-parietal junction (TPJ) corresponds to the onset of OBEs. That weighs heavily against the strong-dualist model. If touching an electrode to the TPJ can cause an OBE, it seems that the causal mechanism of OBEs is in the brain. But strong dualism implies that the ‘soul’ should be the causal mechanism. It is at best difficult and at worst impossible to reconcile a strong-dualist model with the unfolding scientific picture. The other extracorporeal models suggested seem ostensibly compatible with the recent finding, but are not in any way indicated by them. They are like empty efforts to “save the theory” in light of growing momentum toward another an easier explanation.

The emerging scientific evidence shows a link between OBEs and aberrant TPJ activity. The only OBE model gaining evidentiary support by those findings is the physicalist model. As we’ve seen, the TPJ is independently associated with processing data regarding body position in space and estimated points of view of other minds in space. It stands to reason a priori that any brain region that might be found to cause OBEs ought to be involved in computing ‘self’ and ‘other’ positions. Therefore, since mounting evidence suggests exactly that may be the case, confirmation of a key prediction of the physicalist model appears to be unfolding. It stands to reason based on that evidence, that an OBE may constitute a computational mismapping of the spatial region defined ‘self’ in a brain’s internal model of the world. If so, the only world an OBE witness travels into is a mere model in her or his brain of the real world outside.

Thanks to Kevin Langdon for important feedback on strong dualism that influenced both my ‘other models’ and conclusion. This was also published in Noesis 182.

[1] Powell, A.E. (1927). The Astral Body. London: The Theosophical Publishing House.

[2] Metzinger, Thomas (2005). Out-of-body experiences as the origin of the concept of a “soul.” Mind and Matter, 3(1):57-84.

[3] Linklater, Richard (Director). (2001). Waking Life [Motion picture]. United States: Fox.

[4] Tart, Charles (1997). Six Studies of Out-of-the-Body Experiences. Journal of Near Death Studies, March 30, 1997.

[5] Krippner, Stanley (1994). A Pilot Study in ESP, Dreams, and Purported OBEs. 37th Parapsychological Association Convention, August 7-10, 1994, University of Amsterdam.

[6] Osis, Karlis (1989). Life After Death? In Encyclopedia of Death. Editors Robert and Beatrice Kastenbaum. Arizona: Oryx Press, pages 170-4.

[7] Penfield, W., & Perot, P. (1963). The brain’s record of auditory and visual experience. Brain, 86: 595-696.

[8] Blanke, O., Ortigue, S., Landis, T., & Seeck, M. (2002). Stimulating illusory own-body perceptions. Nature, 419(6904): 269-70.

[9] Tong, Frank (2003). Out-of-body experiences: from Penfield to present. Trends in Cognitive Sciences, 7(3):104-106.

[10] Blanke, O., & Arzy, S. (2005). The Out-of-Body Experience: Disturbed Self-Processing at the Temporo-Parietal Junction. Neuroscientist, 11(1):16-24.

[11] Saxe, R., & Kanwisher, N. (2003). People thinking about thinking people: The role of the temporo-parietal junction in “theory of mind.” Neuroimage, 19(4):1835-42.

[12] Aichhorn, M., Perner, J., Kronbichler, M., Staffen, W., & Ladurner, G. (2006). Do visual perspective tasks need theory of mind? Neuroimage, 30(3):1059-68.

[13] Mohr, C., Blanke, O., & Brugger, P. (2006). Perceptual aberrations impair mental own-body transformations. Behavioral Neuroscience, 120(3):528-34.

GODDARD'S JOURNAL

GODDARD'S HOME