Out-of-Body Experience

An out-of-body experience (OBE) is a transient impression of being separated from one's own body. Usually it is associated with three main phenomenological elements: the impression of the self being localized outside one's body (disembodiment), the impression of seeing the world from this elevated perspective (altered first-person perspective), and seeing one's own body below (autoscopy). This entry describes OBE's observed in clinical settings and how OBE has been studied experimentally in healthy participants.

These are, of course, unusual and uncommon experiences, because we normally perceive our self as localized within our bodily borders (embodiment) at a distinct location in space from where we also perceive the world (first-person perspective). Therefore, the scientific study of OBEs offers a unique possibility to gain insights into the functional and neural mechanisms of embodiment, the first-person perspective, and related aspects of self-representation.

OBEs occur in a variety of conditions, such as during sensory deprivation, drug use, certain sleep states, as well as in some forms of psychiatric and neurological disease. OBEs may also occur in healthy people. In particular, the study of neurological OBEs due to epilepsy, migraine, or vascular stroke has revealed some of their functional and neural mechanisms. OBEs of neurological origin are part of a group of disorders that are characterized by illusory reduplication of one's body, but with various degrees of illusory self-location that are associated with vestibular dysfunction. OBEs have been associated with brain damage in the temporoparietal cortex, an area that is strongly involved in multisensory integration of bodily information, such as visual, tactile, and vestibular information about one's own body. Intracranial stimulation of the temporoparietal cortex was shown to evoke vestibular sensations, visuo-tactile, visuo-proprioceptive, or kinesthetic illusions, as well as full-blown OBEs in epileptic patients. These data have highlighted the crucial role of multisensory bodily representations in the temporoparietal cortex in OBEs and self-representation.

Clinical studies do, however, present certain experimental limitations, such as small sample size and limited generalization. Furthermore, they do not explain how the experience of a unitary and stable self (including embodiment and first-person perspective) is achieved under normal conditions. Therefore, several recent studies have utilized knowledge about the mechanisms and phenomenology of OBEs to investigate the influence of multisensory conflicts on bodily self-representations in healthy participants. In 1899, G. M. Stratton carried out self-experiments walking himself with a portable device of mirrors that were aligned in such a way that he could see a projection of his body below him, creating a set-up that allowed him to induce multisensory and sensorimotor conflicts between the seen and the felt position of his body. After wearing this device for ∼24 hours, he reported that he “was mentally outside his own body.” He argued that the visual information about his body dominated the other bodily information (also known as “visual capture”).

In two recent experiments, the influence of multisensory conflicts on global self representations was [Page 712]tested more systematically using a video camera and head-mounted displays (HMDs). In one study, the sitting participant was stroked on the chest with a stick and filmed from the back. On the HMD, participants could see the stick moving in front of the camera, and this generated the feeling of being located at the position of the camera (outside the own body), which was also supported by psychophysiological measurements. In a similar study, standing participants were filmed from behind and saw—via the HMD—either their own body, a fake body, or an object being stroked synchronously or asynchronously with their own body. In conditions when the stroking was synchronous and applied to a bodily (fake or own) character, participants self-identified with the body in front of them and localized the self as drifted toward the front (and thus to a position outside the bodily borders). This suggests that visual capture may influence global body representations, leading to disturbed self-identification, disturbed spatial unity, and, under some conditions, the first-person perspective.

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