scholarly journals Duplication of the bodily self: a perceptual illusion of dual full-body ownership and dual self-location

2020 ◽  
Vol 7 (12) ◽  
pp. 201911
Author(s):  
Arvid Guterstam ◽  
Dennis E. O. Larsson ◽  
Joanna Szczotka ◽  
H. Henrik Ehrsson
Keyword(s):  
Tactile Stimulation ◽  
Sense Of Self ◽  
Body Ownership ◽  
Healthy Human ◽  
Perceptual Illusion ◽  
Person Perspective ◽  
Human Participants ◽  
Third Person Perspective ◽  
Stimulation Of ◽  
Full Body

Previous research has shown that it is possible to use multisensory stimulation to induce the perceptual illusion of owning supernumerary limbs, such as two right arms. However, it remains unclear whether the coherent feeling of owning a full-body may be duplicated in the same manner and whether such a dual full-body illusion could be used to split the unitary sense of self-location into two. Here, we examined whether healthy human participants can experience simultaneous ownership of two full-bodies, located either close in parallel or in two separate spatial locations. A previously described full-body illusion, based on visuo-tactile stimulation of an artificial body viewed from the first-person perspective (1PP) via head-mounted displays, was adapted to a dual-body setting and quantified in five experiments using questionnaires, a behavioural self-location task and threat-evoked skin conductance responses. The results of experiments 1–3 showed that synchronous visuo-tactile stimulation of two bodies viewed from the 1PP lying in parallel next to each other induced a significant illusion of dual full-body ownership. In experiment 4, we failed to find support for our working hypothesis that splitting the visual scene into two, so that each of the two illusory bodies was placed in distinct spatial environments, would lead to dual self-location. In a final exploratory experiment (no. 5), we found preliminary support for an illusion of dual self-location and dual body ownership by using dynamic changes between the 1PPs of two artificial bodies and/or a common third-person perspective in the ceiling of the testing room. These findings suggest that healthy people, under certain conditions of multisensory perceptual ambiguity, may experience dual body ownership and dual self-location. These findings suggest that the coherent sense of the bodily self located at a single place in space is the result of an active and dynamic perceptual integration process.

scholarly journals Top-down recognition leads to a reduced sense of body ownership in individuals with depersonalization tendencies: A focus on full body illusion

2021 ◽  
Author(s):  
Kazuki Yamamoto ◽  
Takashi Nakao
Keyword(s):  
Japanese Version ◽  
The Body ◽  
Body Ownership ◽  
Top Down ◽  
Instruction Condition ◽  
Person Perspective ◽  
Tactile Stimuli ◽  
Self Association ◽  
Third Person Perspective ◽  
Full Body

Sense of body ownership, i.e., the feeling that “my body belongs to me,” has been examined by both the rubber hand illusion (RHI) and full body illusion (FBI). In a study that examined the relationship between RHI and depersonalization, a symptom in which people experience a lower sense of body ownership, the degree of illusion was higher in people with a high depersonalization tendency. However, other reports have suggested that people with depersonalization disorder have difficulty feeling the sense of body ownership. Examination of depersonalization suggests that the negative body recognition in people with depersonalization may make them less likely to feel a sense of body ownership, but this has not yet been examined. In this study, by manipulating top-down recognition (e.g., instructing participants to recognize a fake body as theirs), we clarified the cause of the reduced sense of body ownership in people with a high depersonalization tendency. The FBI procedure was conducted in a virtual reality environment using an avatar as a fake body. The avatar was presented from a third-person perspective, and visual-tactile stimuli were presented to create an illusion. To examine the degree of illusion, we measured the skin conductance responses to the fear stimulus presented after the visual-tactile stimuli presentation. The degree of depersonalization was measured using the Japanese version of the Cambridge Depersonalization Scale. To manipulate the top-down recognition to the avatar, we provided self-association instructions before the presentation of the visual-tactile stimuli. The results showed that participants with a high depersonalization tendency had a lower degree of illusion (rho = -.589, p < .01) in the self-association condition, and a higher one (rho = .552, p < .01) in the non-association instruction condition. This indicates that although people with a high depersonalization tendency are more likely to feel a sense of body ownership through the integration of visual-tactile stimuli, top-down recognition of the body as one’s own leads to a decrease in the sense of body ownership.

scholarly journals Contributions of Body-Orientation to Mental Ball Dropping Task During Out-of-Body Experiences

2022 ◽  
Vol 15 ◽  
Author(s):  
Ege Tekgün ◽  
Burak Erdeniz
Keyword(s):  
Body Position ◽  
Body Orientation ◽  
First Person ◽  
Body Ownership ◽  
Person Perspective ◽  
Body Experiences ◽  
Significant Difference ◽  
Third Person Perspective ◽  
Full Body ◽  
Virtual Avatar

Out-of-body experiences (OBEs) provide fascinating insights into our understanding of bodily self-consciousness and the workings of the brain. Studies that examined individuals with brain lesions reported that OBEs are generally characterized by participants experiencing themselves outside their physical body (i.e., disembodied feeling) (Blanke and Arzy, 2005). Based on such a characterization, it has been shown that it is possible to create virtual OBEs in immersive virtual environments (Ehrsson, 2007; Ionta et al., 2011b; Bourdin et al., 2017). However, the extent to which body-orientation influences virtual OBEs is not well-understood. Thus, in the present study, 30 participants (within group design) experienced a full-body ownership illusion (synchronous visuo-tactile stimulation only) induced with a gender-matched full-body virtual avatar seen from the first-person perspective (1PP). At the beginning of the experiment, participants performed a mental ball dropping (MBD) task, seen from the location of their virtual avatar, to provide a baseline measurement. After this, a full-body ownership illusion (embodiment phase) was induced in all participants. This was followed by the virtual OBE illusion phase of the experiment (disembodiment phase) in which the first-person viewpoint was switched to a third-person perspective (3PP), and participants' disembodied viewpoint was gradually raised to 14 m above the virtual avatar, from which altitude they repeated the MBD task. During the experiment, this procedure was conducted twice, and the participants were allocated first to the supine or the standing body position at random. Results of the MBD task showed that the participants experienced increased MBD durations during the supine condition compared to the standing condition. Furthermore, although the findings from the subjective reports confirmed the previous findings of virtual OBEs, no significant difference between the two postures was found for body ownership. Taken together, the findings of the current study make further contributions to our understanding of both the vestibular system and time perception during OBEs.

scholarly journals Experiential ownership and body ownership are different phenomena

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Caleb Liang ◽  
Wen-Hsiang Lin ◽  
Tai-Yuan Chang ◽  
Chi-Hong Chen ◽  
Chen-Wei Wu ◽  
...  
Keyword(s):  
Conscious Experience ◽  
Distinct Type ◽  
Body Part ◽  
The Body ◽  
Body Ownership ◽  
Rubber Hand ◽  
Person Perspective ◽  
The One ◽  
First Time ◽  
Full Body

AbstractBody ownership concerns what it is like to feel a body part or a full body as mine, and has become a prominent area of study. We propose that there is a closely related type of bodily self-consciousness largely neglected by researchers—experiential ownership. It refers to the sense that I am the one who is having a conscious experience. Are body ownership and experiential ownership actually the same phenomenon or are they genuinely different? In our experiments, the participant watched a rubber hand or someone else’s body from the first-person perspective and was touched either synchronously or asynchronously. The main findings: (1) The sense of body ownership was hindered in the asynchronous conditions of both the body-part and the full-body experiments. However, a strong sense of experiential ownership was observed in those conditions. (2) We found the opposite when the participants’ responses were measured after tactile stimulations had ceased for 5 s. In the synchronous conditions of another set of body-part and full-body experiments, only experiential ownership was blocked but not body ownership. These results demonstrate for the first time the double dissociation between body ownership and experiential ownership. Experiential ownership is indeed a distinct type of bodily self-consciousness.

The structure of self-experience during visuo–tactile stimulation of a virtual and the physical body

2012 ◽  
Vol 25 (0) ◽  
pp. 214
Author(s):  
Martin Dobricki ◽  
Betty J. Mohler ◽  
Heinrich H. Bülthoff
Keyword(s):  
Tactile Stimulation ◽  
Conscious Experience ◽  
Body Ownership ◽  
Spatial Presence ◽  
Cronbach’S Alpha ◽  
Head Mounted Display ◽  
Cronbach's Alpha ◽  
Distinct Category ◽  
Self Motion ◽  
Stimulation Of

The simultaneous visuo–tactile stimulation of an individual’s body and a virtual body (avatar) is an experimental method used to investigate the mechanisms of self-experience. Studies incorporating this method found that it elicits the experience of bodily ownership over the avatar. Moreover, as part of our own research we found that it also has an effect on the experience of agency, spatial presence, as well as on the perception of self-motion, and thus on self-localization. However, it has so far not been investigated whether these effects represent distinct categories within conscious experience. We stroked the back of 21 male participants for three minutes while they watched an avatar getting synchronously stroked within a virtual city in a head-mounted display setup. Subsequently, we assessed their avatar and their spatial presence experience with 23 questionnaire items. The analysis of the responses to all items by means of nonmetric multidimensional scaling resulted in a two-dimensional map (stress = 0.151) on which three distinct categories of items could be identified: a cluster (Cronbach’s alpha = 0.89) consisting of all presence items, a cluster (Cronbach’s alpha = 0.88) consisting of agency-related items, and a cluster (Cronbach’s alpha = 0.93) consisting of items related to body ownership as well as self-localization. The reason that spatial presence formed a distinct category could be that body ownership, self-localization and agency are not reported in relation to space. Body ownership and self-localization belonged to the same category which we named identification phenomena. Hence, we propose the following three higher-order categories of self-experience: identification, agency, and spatial presence.

scholarly journals Empathy or Ownership? Evidence from Corticospinal Excitability Modulation during Pain Observation

2016 ◽  
Vol 28 (11) ◽  
pp. 1760-1771 ◽  
Author(s):  
Giulia Bucchioni ◽  
Carlotta Fossataro ◽  
Andrea Cavallo ◽  
Harold Mouras ◽  
Marco Neppi-Modona ◽  
...  
Keyword(s):  
The Body ◽  
First Person ◽  
Body Ownership ◽  
Physiological Basis ◽  
Hand Model ◽  
Person Perspective ◽  
Third Person ◽  
First Person Perspective ◽  
Third Person Perspective ◽  
The One

Recent studies show that motor responses similar to those present in one's own pain (freezing effect) occur as a result of observation of pain in others. This finding has been interpreted as the physiological basis of empathy. Alternatively, it can represent the physiological counterpart of an embodiment phenomenon related to the sense of body ownership. We compared the empathy and the ownership hypotheses by manipulating the perspective of the observed hand model receiving pain so that it could be a first-person perspective, the one in which embodiment occurs, or a third-person perspective, the one in which we usually perceive the others. Motor-evoked potentials (MEPs) by TMS over M1 were recorded from first dorsal interosseous muscle, whereas participants observed video clips showing (a) a needle penetrating or (b) a Q-tip touching a hand model, presented either in first-person or in third-person perspective. We found that a pain-specific inhibition of MEP amplitude (a significantly greater MEP reduction in the “pain” compared with the “touch” conditions) only pertains to the first-person perspective, and it is related to the strength of the self-reported embodiment. We interpreted this corticospinal modulation according to an “affective” conception of body ownership, suggesting that the body I feel as my own is the body I care more about.

scholarly journals The Redundant Signals Effect and the Full Body Illusion: not Multisensory, but Unisensory Tactile Stimuli Are Affected by the Illusion

2021 ◽  
pp. 1-33
Author(s):  
Lieke M. J. Swinkels ◽  
Harm Veling ◽  
Hein T. van Schie
Keyword(s):  
Multisensory Integration ◽  
Objective Measure ◽  
Race Model ◽  
Detection Task ◽  
Head Mounted Display ◽  
Person Perspective ◽  
Tactile Stimuli ◽  
Third Person Perspective ◽  
Full Body ◽  
Virtual Body

Abstract During a full body illusion (FBI), participants experience a change in self-location towards a body that they see in front of them from a third-person perspective and experience touch to originate from this body. Multisensory integration is thought to underlie this illusion. In the present study we tested the redundant signals effect (RSE) as a new objective measure of the illusion that was designed to directly tap into the multisensory integration underlying the illusion. The illusion was induced by an experimenter who stroked and tapped the participant’s shoulder and underarm, while participants perceived the touch on the virtual body in front of them via a head-mounted display. Participants performed a speeded detection task, responding to visual stimuli on the virtual body, to tactile stimuli on the real body and to combined (multisensory) visual and tactile stimuli. Analysis of the RSE with a race model inequality test indicated that multisensory integration took place in both the synchronous and the asynchronous condition. This surprising finding suggests that simultaneous bodily stimuli from different (visual and tactile) modalities will be transiently integrated into a multisensory representation even when no illusion is induced. Furthermore, this finding suggests that the RSE is not a suitable objective measure of body illusions. Interestingly however, responses to the unisensory tactile stimuli in the speeded detection task were found to be slower and had a larger variance in the asynchronous condition than in the synchronous condition. The implications of this finding for the literature on body representations are discussed.

scholarly journals Enhancing Virtual Walking Sensation Using Self-Avatar in First-Person Perspective and Foot Vibrations

2021 ◽  
Vol 2 ◽  
Author(s):  
Yusuke Matsuda ◽  
Junya Nakamura ◽  
Tomohiro Amemiya ◽  
Yasushi Ikei ◽  
Michiteru Kitazaki
Keyword(s):  
First Person ◽  
The Third ◽  
Person Perspective ◽  
Third Person ◽  
First Person Perspective ◽  
Third Person Perspective ◽  
Hands And Feet ◽  
Self Motion ◽  
The Third Person ◽  
Full Body

Walking is a fundamental physical activity in humans. Various virtual walking systems have been developed using treadmill or leg-support devices. Using optic flow, foot vibrations simulating footsteps, and a walking avatar, we propose a virtual walking system that does not require limb action for seated users. We aim to investigate whether a full-body or hands-and-feet-only walking avatar with either the first-person (experiment 1) or third-person (experiment 2) perspective can convey the sensation of walking in a virtual environment through optic flows and foot vibrations. The viewing direction of the virtual camera and the head of the full-body avatar were linked to the actual user's head motion. We discovered that the full-body avatar with the first-person perspective enhanced the sensations of walking, leg action, and telepresence, either through synchronous or asynchronous foot vibrations. Although the hands-and-feet-only avatar with the first-person perspective enhanced the walking sensation and telepresence, compared with the no-avatar condition, its effect was less prominent than that of the full-body avatar. However, the full-body avatar with the third-person perspective did not enhance the sensations of walking and leg action; rather, it impaired the sensations of self-motion and telepresence. Synchronous or rhythmic foot vibrations enhanced the sensations of self-motion, waking, leg action, and telepresence, irrespective of the avatar condition. These results suggest that the full-body or hands-and-feet avatar is effective for creating virtual walking experiences from the first-person perspective, but not the third-person perspective, and that the foot vibrations simulating footsteps are effective, regardless of the avatar condition.

scholarly journals The Influence of Embodiment as a Cartoon Character on Public Speaking Anxiety

2021 ◽  
Vol 2 ◽  
Author(s):  
Anna I. Bellido Rivas ◽  
Xavi Navarro ◽  
Domna Banakou ◽  
Ramon Oliva ◽  
Veronica Orvalho ◽  
...  
Keyword(s):  
Public Speaking ◽  
Human Condition ◽  
Public Speaking Anxiety ◽  
Body Ownership ◽  
Speaking Anxiety ◽  
Person Perspective ◽  
Cartoon Character ◽  
Third Person Perspective ◽  
The Impact ◽  
Virtual Body

Virtual Reality can be used to embody people in different types of body—so that when they look towards themselves or in a mirror they will see a life-sized virtual body instead of their own, and that moves with their own movements. This will typically give rise to the illusion of body ownership over the virtual body. Previous research has focused on embodiment in humanoid bodies, albeit with various distortions such as an extra limb or asymmetry, or with a body of a different race or gender. Here we show that body ownership also occurs over a virtual body that looks like a cartoon rabbit, at the same level as embodiment as a human. Furthermore, we explore the impact of embodiment on performance as a public speaker in front of a small audience. Forty five participants were recruited who had public speaking anxiety. They were randomly partitioned into three groups of 15, embodied as a Human, as the Cartoon rabbit, or from third person perspective (3PP) with respect to the rabbit. In each condition they gave two talks to a small audience of the same type as their virtual body. Several days later, as a test condition, they returned to give a talk to an audience of human characters embodied as a human. Overall, anxiety reduced the most in the Human condition, the least in the Cartoon condition, and there was no change in the 3PP condition, taking into account existing levels of trait anxiety. We show that embodiment in a cartoon character leads to high levels of body ownership from the first person perspective and synchronous real and virtual body movements. We also show that the embodiment influences outcomes on the public speaking task.

scholarly journals The relationship between virtual body ownership and temperature sensitivity

2013 ◽  
Vol 10 (85) ◽  
pp. 20130300 ◽  
Author(s):  
Joan Llobera ◽  
M. V. Sanchez-Vives ◽  
Mel Slater
Keyword(s):  
Temperature Sensitivity ◽  
Tactile Stimulation ◽  
Body Ownership ◽  
Rubber Hand ◽  
The Real ◽  
Person Perspective ◽  
Visual Presence ◽  
Palm Of The Hand ◽  
Real Hand ◽  
Virtual Body

In the rubber hand illusion, tactile stimulation seen on a rubber hand, that is synchronous with tactile stimulation felt on the hidden real hand, can lead to an illusion of ownership over the rubber hand. This illusion has been shown to produce a temperature decrease in the hidden hand, suggesting that such illusory ownership produces disownership of the real hand. Here, we apply immersive virtual reality (VR) to experimentally investigate this with respect to sensitivity to temperature change. Forty participants experienced immersion in a VR with a virtual body (VB) seen from a first-person perspective. For half the participants, the VB was consistent in posture and movement with their own body, and in the other half, there was inconsistency. Temperature sensitivity on the palm of the hand was measured before and during the virtual experience. The results show that temperature sensitivity decreased in the consistent compared with the inconsistent condition. Moreover, the change in sensitivity was significantly correlated with the subjective illusion of virtual arm ownership but modulated by the illusion of ownership over the full VB. This suggests that a full body ownership illusion results in a unification of the virtual and real bodies into one overall entity—with proprioception and tactile sensations on the real body integrated with the visual presence of the VB. The results are interpreted in the framework of a ‘body matrix’ recently introduced into the literature.

Sign in / Sign up

Export Citation Format

Share Document