The second me: Seeing the real body during humanoid robot embodiment produces an illusion of bi-location

Whole-body embodiment studies have shown that synchronized multi-sensory cues can trick a healthy human mind to perceive self-location outside the bodily borders, producing an illusion that resembles an out-of-body experience (OBE). But can a healthy mind also perceive the sense of self in more than one body at the same time? To answer this question, we created a novel artificial reduplication of one’s body using a humanoid robot embodiment system. We first enabled individuals to embody the humanoid robot by providing them with audio-visual feedback and control of the robot head movements and walk, and then explored the self-location and self-identification perceived by them when they observed themselves through the embodied robot. Our results reveal that, when individuals are exposed to the humanoid body reduplication, they experience an illusion that strongly resembles heautoscopy, suggesting that a healthy human mind is able to bi-locate in two different bodies simultaneously.     

Disowning one's seen real body during an out-of-body illusion

Under normal circumstances, we experience that our center of awareness is located behind our eyes and inside our own body. To learn more about the perceptual processes that underlie this tight coupling between the spatial dimensions of our consciously perceived self and our physical body, we conducted a series of experiments using an 'out-of-body illusion'. In this illusion, the conscious sense of self is displaced in the testing room by experimental manipulation of the congruency of visual and tactile information and a change in the visual perspective. We demonstrate that when healthy individuals experience that they are located in a different place from their real body, they disown this body and no longer perceive it as part of themselves. Our findings are important because they reveal a relationship between the representation of self-location in the local environment and the multisensory representation of one's own body.     

Autoscopic phenomena and one's own body representation in dreams

Autoscopic phenomena (AP) are complex experiences that include the visual illusory reduplication of one’s own body. From a phenomenological point of view, we can distinguish three conditions: autoscopic hallucinations, heautoscopy, and out-of-body experiences. The dysfunctional pattern involves multisensory disintegration of personal and extrapersonal space perception. The etiology, generally either neurological or psychiatric, is different. Also, the hallucination of Self and own body image is present during dreams and differs according to sleep stage. Specifically, the representation of the Self in REM dreams is frequently similar to the perception of Self in wakefulness, whereas in NREM dreams, a greater polymorphism of Self and own body representation is observed. The parallels between autoscopic phenomena in pathological cases and the Self-hallucination in dreams will be discussed to further the understanding of the particular states of self awareness, especially the complex integration of different memory sources in Self and body representation.     

On The Nature of Experiencing Self‐Agency: The Role of Goals and Primes in Inferring Oneself as the Cause of Behavior

People often find themselves in situations where the cause of events may be ambiguous. Surprisingly though, the experience of self‐agency, i.e., perceiving oneself as the causal agent of behavioral outcomes, appears quite natural to most people. How then do these experiences arise? We discuss common models proposing that self‐agency experiences result from the comparison between actual action‐outcomes and the outcomes one explicitly set as a goal. However, recent developments in psychology and neuroscience suggest that our behaviors and the outcomes they produce can be primed and implicitly guided by environmental cues and yet are accompanied by experiences of self‐agency. Hence, we also review research revealing how self‐agency experiences may arise over behavioral outcomes that are implicitly primed before they occur and how such implicitly cued agency experiences may differ from agency experiences that are the result of explicitly set goals. Directions for future research are briefly addressed.     

Similarities between near-death experiences and multiple personality disorder

In this paper I compare the phenomenology of near-death experiences to that of multiple personality disorder. The comparison reveals a number of similarities, including out-of-body experiences, the transcendental environment, encounter with the higher self, possible temporal lobe involvement, and antecedent child abuse. Rather than being disparate and unrelated experiences, I suggest that the near-death experience and multiple personality disorder may be variants of the same basic phenomenological pattern.     

The phantom leaf effect and its implications for near-death and out-of-body experiences

The phantom leaf effect seen in Kirlian photography may help researchers better understand near-death and out-of-body experience. While the process responsible for the phantom leaf effect is unknown, variations of Rupert Sheldrake's morphogenetic field theory offer three explanations for this phenomenon. Each of these variations has different implications for near-death and out-of-body experiences.     

Visual perception during naturalistic near-death out-of-body experiences

This study attempted to ascertain the most appropriate content and placement of visual stimuli in a hospital-based study of the veridicality of out-of-body perception in the near-death experience (NDE), and the likelihood that a subject in such a study would notice, clearly perceive, and accurately recall a visual stimulus. Based on the questionnaire responses of 63 subjects who had near-death out-of-body experiences (ND OBEs), at least some of the respondents described sufficiently complete and accurate visual perception during the experience to warrant the pursuit of veridicality research in hospitals. Recommended stimulus content for such research includes a surface with intense color and lighting, and simple number and/or letter combinations. Stimuli should be as far below ceiling level as possible while maintaining double-blind criteria. Some characteristics of the individual NDE and NDEr may affect veridical perception during the ND OBE.This paper was derived in part from her Ed.D. dissertation submitted to the Northern Illinois University Graduate School.     

Further evidence for veridical perception during near-death experiences

We briefly survey research designed to validate alleged out-of-body perceptions during near-death experiences. Most accounts of this kind that have surfaced since Michael Sabom's work are unsubstantiated self-reports or, as in claims of visual perception of blind persons, completely undocumented or fictional, but there have been some reports that were corroborated by witnesses. We briefly present and discuss three new cases of this kind.     

Body ownership affects visual perception of object size by rescaling the visual representation of external space

Size perception is most often explained by a combination of cues derived from the visual system. However, this traditional cue approach neglects the role of the observer’s body beyond mere visual comparison. In a previous study, we used a full-body illusion to show that objects appear larger and farther away when participants experience a small artificial body as their own and that objects appear smaller and closer when they assume ownership of a large artificial body (“Barbie-doll illusion”; van der Hoort, Guterstam, & Ehrsson, PLoS ONE, 6(5), e20195, 2011). The first aim of the present study was to test the hypothesis that this own-body-size effect is distinct from the role of the seen body as a direct familiar-size cue. To this end, we developed a novel setup that allowed for occlusion of the artificial body during the presentation of test objects. Our results demonstrate that the feeling of ownership of an artificial body can alter the perceived sizes of objects without the need for a visible body. Second, we demonstrate that fixation shifts do not contribute to the own-body-size effect. Third, we show that the effect exists in both peri-personal space and distant extra-personal space. Finally, through a meta-analysis, we demonstrate that the own-body-size effect is independent of and adds to the classical visual familiar-size cue effect. Our results suggest that, by changing body size, the entire spatial layout rescales and new objects are now perceived according to this rescaling, without the need to see the body.     

Out-of-body experiences: from Penfield to present

Can the brain, when stimulated, yield entirely novel experiences? Blanke et al. (2002) describe a patient who reported spontaneous out-of-body experiences during electrical stimulation of her angular gyrus. These findings, although apparently extraordinary, agree with much earlier reports from a patient tested by Wilder Penfield. Such studies can provide clues about the nature of conscious experience.     

Dissociative alterations in body image among individuals reporting out-of-body experiences: a conceptual replication

A conceptual replication of the link between self-reported dissociative alterations in body-image under experimental conditions and the reporting of prior out-of-body experiences in a recent data set was undertaken. Also examined was whether this relationship would hold for experiences reported during the experimental context and whether it is independent of self-reported New Age belief. Data from mostly undergraduates (N= 40; M age = 33.5, SD = 12.5; 27 women) in a mirror-gazing study were retrospectively analyzed. The 9 individuals who reported prior out-of-body experiences, relative to those 31 who did not, exhibited significantly greater self-reported dissociative alterations in body-image during the mirror-gazing task, even when the influence of scores on New Age belief was controlled for statistically. The same differential relationship was not found between 6 individuals who did and 34 who did not report out-of-body experiences during the task.     

Possessions and Self in the Identity Work of Survivors of Domestic Violence

Domestic violence has serious consequences for survivors, including severe effects on psychological well‐being and identity. This article reveals the previously hidden possession experiences and identity work of domestic violence survivors. Using a novel visual research method that features material objects as visual stimuli to elicit data, we found possessions were critical in the complex identity work undertaken by survivors. Emergent themes detailing the role of possessions in coping with ongoing self‐threats by an intimate partner provide empirical support for the conceptualization of diametrically opposed selves, the Prescribed Self and Agentic Self. These opposite and compartmentalized selves enabled survivors to cope with extreme disintegration and destabilization of self by the abuser. As well as the conceptual and methodological contributions we make to the possessions‐self literature in consumer research and psychology, this research is valuable for designing social service programs to help survivors cope with the effects of domestic violence on identity.     

Illusory own body perceptions: Case reports and relevance for bodily self-consciousness

Neurological disorders of body representation have for a long time suggested the importance of multisensory processing of bodily signals for self-consciousness. One such group of disorders – illusory own body perceptions affecting the entire body – has been proposed to be especially relevant in this respect, based on neurological data as well as philosophical considerations. This has recently been tested experimentally in healthy subjects showing that integration of multisensory bodily signals from the entire body with respect to the three aspects: self-location, first-person perspective, and self-location, is crucial for bodily self-consciousness. Here we present clinical and neuroanatomical data of two neurological patients with paroxysmal disorders of full body representation in whom only one of these aspects, self-identification, was abnormal. We distinguish such disorders of global body representation from related but distinct disorders and discuss their relevance for the neurobiology of bodily self-consciousness.     

At the Edge of Eternity's Shadows: Scaling the Fractal Continuum from Lower into Higher Space

In this paper, I elaborate the hyperspatial implications of the fractal-scaling scheme that I introduced previously. Four case examples where out-of-body experiencers reported heightened and amplified visual capacities are correlated with this explanatory model. Three of these cases are identified as including an additional hyperspace signifier, the reported capacity to see through solid and opaque physical obstructions. One of these cases included yet another hyperspace signifier, the reported capacity to pass through such obstructions. Additional evidence supportive of this thesis is drawn from the literature on ecstatic experience, including out-of-body, near-death, and other varieties of mystical or visionary experience, and from that on psychedelic experience. Yet other hyperspace signifiers reported by ecstatic voyagers are also considered, including sensations of seeing outward spherically in 360 degrees and of seeing on all sides of three-dimensional solids simultaneously.     

Visual cues of motion that trigger animacy perception at birth: the case of self‐propulsion

Self‐propelled motion is a powerful cue that conveys information that an object is animate. In this case, animate refers to an entity's capacity to initiate motion without an applied external force. Sensitivity to this motion cue is present in infants that are a few months old, but whether this sensitivity is experience‐dependent or is already present at birth is unknown. Here, we tested newborns to examine whether predispositions to process self‐produced motion cues underlying animacy perception were present soon after birth. We systematically manipulated the onset of motion by self‐propulsion (Experiment 1) and the change in trajectory direction in the presence or absence of direct contact with an external object (Experiments 2 and 3) to investigate how these motion cues determine preference in newborns. Overall, data demonstrated that, at least at birth, the self‐propelled onset of motion is a crucial visual cue that allowed newborns to differentiate between self‐ and non‐self‐propelled objects (Experiment 1) because when this cue was removed, newborns did not manifest any visual preference (Experiment 2), even if they were able to discriminate between the stimuli (Experiment 3). To our knowledge, this is the first study aimed at identifying sensitivity in human newborns to the most basic and rudimentary motion cues that reliably trigger perceptions of animacy in adults. Our findings are compatible with the hypothesis of the existence of inborn predispositions to visual cues of motion that trigger animacy perception in adults.     

Intermodal sensory image generation: An fMRI analysis

Although both imagery and perception may be related to more than one sensory input, and information coming from different sensory channels is often integrated in a unique mental representation, most recent neuroimaging literature has focused on visual imaging. Contrasting results have been obtained concerning the sharing of the same mechanisms by visual perception and visual imagery, in part due to assessment techniques and to interindividual variability in brain activation. In recent years, an increasing number of researchers have adopted novel neuroimaging techniques in order to investigate intermodal connections in mental imagery and have reported a high degree of interaction between mental imagery and other cognitive functions. In the present study the specific nature of mental imagery was investigated by means of fMRI on a more extensive set of perceptual experiences (shapes, sounds, touches, odours, flavours, self‐perceived movements, and internal sensations). Results show that the left middle‐inferior temporal area is recruited by mental imagery for all modalities investigated and not only for the visual one, while parietal and prefrontal areas exhibit a more heterogeneous pattern of activation across modalities. The prominent left lateralisation observed for almost all the conditions suggests that verbal cues affect the processes underlying the generation of images.     

Out-of-Body experiences in the blind

The theoretical significance of out-of-body experiences in blind people is explored. In this context I report results of a survey of a small sample of blind adults. It is concluded that we have yet to locate a case of an out-of-body experience in the blind that has critical implications for the interpretation of the experience among the general population.Acknowledgement hereby is given to the efforts of Margaret Kerr, Coordinator of Field Services for the Royal Blind Society of New South Wales, Australia, in supervising the collection of data reported in this paper.     

Assessing the influence of schematic drawings of body parts on tactile discrimination performance using the crossmodal congruency task

Seeing one's own body (either directly or indirectly) can influence visuotactile crossmodal interactions. Recently, it has been shown that even viewing a simple line drawing of a hand can also modulate such crossmodal interactions, as if the picture of the hand somehow corresponds to (or primes) the participants' own hand. Alternatively, however, it could be argued that the modulatory effects of viewing the picture of a hand on visuotactile interactions might simply be attributed to cognitive processes such as the semantic referral to the relevant body part or to the orientation cues provided by the hand picture instead. In the present study, we evaluated these various different interpretations of the hand picture effect. Participants made speeded discrimination responses to the location of brief vibrotactile targets presented to either the tip or base of their forefinger, while trying to ignore simultaneously-presented visual distractors presented to either side of central fixation. We compared the modulatory effect of the picture of a hand with that seen when the visual distractors were presented next to words describing the tip and base of the forefinger (Experiment 1), or were superimposed over arrows which provided another kind of directional cue (Experiment 2). Tactile discrimination performance was modulated in the hand picture condition, but not in the word or arrow conditions. These results therefore suggest that visuotactile interactions are specifically modulated by the image of the hand rather than by cognitive cues such as simply semantic referral to the relevant body sites and/or any visual orientation cues provided by the picture of a hand.     

Interpretation of human pointing by African elephants: generalisation and rationality

Factors influencing the abilities of different animals to use cooperative social cues from humans are still unclear, in spite of long-standing interest in the topic. One of the few species that have been found successful at using human pointing is the African elephant (Loxodonta africana); despite few opportunities for learning about pointing, elephants follow a pointing gesture in an object-choice task, even when the pointing signal and experimenter’s body position are in conflict, and when the gesture itself is visually subtle. Here, we show that the success of captive African elephants at using human pointing is not restricted to situations where the pointing signal is sustained until the time of choice: elephants followed human pointing even when the pointing gesture was withdrawn before they had responded to it. Furthermore, elephants rapidly generalised their response to a type of social cue they were unlikely to have seen before: pointing with the foot. However, unlike young children, they showed no sign of evaluating the ‘rationality’ of this novel pointing gesture according to its visual context: that is, whether the experimenter’s hands were occupied or not.