scholarly journals Challenging the boundaries of the physical self: purely distal cues in the environment impact body ownership

2019 ◽  
Author(s):  
Klaudia Grechuta ◽  
Javier De La Torre ◽  
Belén Rubio Ballester ◽  
Paul F.M.J. Verschure
Keyword(s):  
The Body ◽  
Body Ownership ◽  
Environment Impact ◽  
Rubber Hand ◽  
Sensory Stimuli ◽  
Sensory Signals ◽  
Surrounding Environment ◽  
Tactile Stimuli ◽  
Multisensory Cues ◽  
Multisensory Information

AbstractThe unique ability to identify one’s own body and experience it as one’s own is fundamental in goal-oriented behavior and survival. However, the mechanisms underlying the so-called body ownership are yet not fully understood. The plasticity of body ownership has been studied using two experimental methods or their variations. Specifically, the Rubber Hand Illusion (RHI), where the tactile stimuli are externally generated, or the moving RHI which implies self-initiated movements. Grounded in these paradigms, evidence has demonstrated that body ownership is a product of bottom-up reception of self- and externally-generated multisensory information and top-down comparison between the predicted and the actual sensory stimuli. Crucially, provided the design of the current paradigms, where one of the manipulated cues always involves the processing of a proximal modality sensing the body or its surface (e.g., touch), the contribution of sensory signals which pertain to the environment remain elusive. Here we propose that, as any robust percept, body ownership depends on the integration and prediction of all the sensory stimuli, and therefore it will depend on the consistency of purely distal sensory signals pertaining to the environment. To test our hypothesis, we create an embodied goal-oriented task and manipulate the predictability of the surrounding environment by changing the congruency of purely distal multisensory cues while preserving bodily and action-driven signals entirely predictable. Our results empirically reveal that the way we represent our body is contingent upon all the sensory stimuli including purely distal and action-independent signals which pertain to the environment.

scholarly journals Challenging the Boundaries of the Physical Self: Distal Cues Impact Body Ownership

2021 ◽  
Vol 15 ◽  
Author(s):  
Klaudia Grechuta ◽  
Javier De La Torre Costa ◽  
Belén Rubio Ballester ◽  
Paul Verschure
Keyword(s):  
The Body ◽  
Three Dimensions ◽  
Body Ownership ◽  
Feedback Processing ◽  
Subjective Report ◽  
Sensory Stimuli ◽  
Sensory Signals ◽  
Sensory Modalities ◽  
Multisensory Cues ◽  
Multisensory Information

The unique ability to identify one’s own body and experience it as one’s own is fundamental in goal-oriented behavior and survival. However, the mechanisms underlying the so-called body ownership are yet not fully understood. Evidence based on Rubber Hand Illusion (RHI) paradigms has demonstrated that body ownership is a product of reception and integration of self and externally generated multisensory information, feedforward and feedback processing of sensorimotor signals, and prior knowledge about the body. Crucially, however, these designs commonly involve the processing of proximal modalities while the contribution of distal sensory signals to the experience of ownership remains elusive. Here we propose that, like any robust percept, body ownership depends on the integration and prediction across all sensory modalities, including distal sensory signals pertaining to the environment. To test our hypothesis, we created an embodied goal-oriented Virtual Air Hockey Task, in which participants were to hit a virtual puck into a goal. In two conditions, we manipulated the congruency of distal multisensory cues (auditory and visual) while preserving proximal and action-driven signals entirely predictable. Compared to a fully congruent condition, our results revealed a significant decrease on three dimensions of ownership evaluation when distal signals were incongruent, including the subjective report as well as physiological and kinematic responses to an unexpected threat. Together, these findings support the notion that the way we represent our body is contingent upon all the sensory stimuli, including distal and action-independent signals. The present data extend the current framework of body ownership and may also find applications in rehabilitation scenarios.

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.

scholarly journals Perception of visual-tactile asynchrony, bodily perceptual aberrations, and bodily illusions in schizophrenia

2020 ◽  
Author(s):  
Regine Zopf
Keyword(s):  
The Body ◽  
Detection Sensitivity ◽  
Body Ownership ◽  
Body Perception ◽  
Rubber Hand ◽  
Bodily Experiences ◽  
Asynchrony Detection ◽  
Body Perceptions ◽  
Proprioceptive Drift ◽  
Insight Into

Body perception can be dramatically altered in individuals with schizophrenia resulting in experiences of undefined bodily boundaries, loss of body ownership, and size changes for parts of the body. These individuals may also be more susceptible to the rubber hand illusion (RHI: an illusion of body perception that can also be induced in neurotypical populations), but the findings are mixed. Furthermore, the perception of timing information about multisensory stimuli, which is thought to be fundamental for body perception, has been reported to be altered in schizophrenia. We tested here whether altered perception of the temporal relationship between visual and tactile signals in schizophrenia can predict self-reported perceptual aberrations and RHI susceptibility (indexed by both illusion self-ratings and a more objective proprioceptive-drift measure). We found that the sensitivity to detect temporal asynchronies is reduced in schizophrenia and this predicts bodily perceptual symptoms. In contrast, we found no evidence for a direct relationship between asynchrony detection sensitivity and RHI susceptibility. Instead, our findings suggest that experiencing more bodily perceptual symptoms increases the likelihood of endorsing unusual bodily experiences, resulting in higher RHI self-ratings but not higher proprioceptive-drift scores. Overall, our findings provide evidence for both direct and indirect links between temporal and body perception and thus new insight into the mechanisms that may underlie unusual body perceptions in schizophrenia.

scholarly journals Body ownership and agency altered by an electromyographically controlled robotic arm

2018 ◽  
Vol 5 (5) ◽  
pp. 172170 ◽  
Author(s):  
Yuki Sato ◽  
Toshihiro Kawase ◽  
Kouji Takano ◽  
Charles Spence ◽  
Kenji Kansaku
Keyword(s):  
Cognitive Neuroscience ◽  
The Body ◽  
Sense Of Agency ◽  
Robotic Arm ◽  
Body Ownership ◽  
Fundamental Issue ◽  
Rubber Hand ◽  
Sense Of Ownership ◽  
Robotic Prosthesis ◽  
Wrist Flexors

Understanding how we consciously experience our bodies is a fundamental issue in cognitive neuroscience. Two fundamental components of this are the sense of body ownership (the experience of the body as one's own) and the sense of agency (the feeling of control over one's bodily actions). These constructs have been used to investigate the incorporation of prostheses. To date, however, no evidence has been provided showing whether representations of ownership and agency in amputees are altered when operating a robotic prosthesis. Here we investigated a robotic arm using myoelectric control, for which the user varied the joint position continuously, in a rubber hand illusion task. Fifteen able-bodied participants and three trans-radial amputees were instructed to contract their wrist flexors/extensors alternately, and to watch the robotic arm move. The sense of ownership in both groups was extended to the robotic arm when the wrists of the real and robotic arm were flexed/extended synchronously, with the effect being smaller when they moved in opposite directions. Both groups also experienced a sense of agency over the robotic arm. These results suggest that these experimental settings induced successful incorporation of the prosthesis, at least for the amputees who took part in the present study.

The Rubber Hand Illusion in Healthy Younger and Older Adults

2018 ◽  
Vol 31 (6) ◽  
pp. 537-555 ◽  
Author(s):  
Jennifer L. Campos ◽  
Graziella El-Khechen Richandi ◽  
Babak Taati ◽  
Behrang Keshavarz
Keyword(s):  
Skin Temperature ◽  
Subjective Experience ◽  
Age Groups ◽  
Objective Measure ◽  
The Body ◽  
Rubber Hand Illusion ◽  
Body Ownership ◽  
Rubber Hand ◽  
Age Related ◽  
Body Change

Percepts about our body’s position in space and about body ownership are informed by multisensory feedback from visual, proprioceptive, and tactile inputs. The Rubber Hand Illusion (RHI) is a multisensory illusion that is induced when an observer sees a rubber hand being stroked while they feel their own, spatially displaced, and obstructed hand being stroked. When temporally synchronous, the visual–tactile interactions can create the illusion that the rubber hand belongs to the observer and that the observer’s real hand is shifted in position towards the rubber hand. Importantly, little is understood about whether these multisensory perceptions of the body change with older age. Thus, in this study we implemented a classic RHI protocol (synchronous versus asynchronous stroking) with healthy younger (18–35) and older (65+) adults and measured the magnitude of proprioceptive drift and the subjective experience of body ownership. As an adjunctive objective measure, skin temperature was recorded to evaluate whether decreases in skin temperature were associated with illusory percepts, as has been shown previously. The RHI was observed for both age groups with respect to increased drift and higher ratings of ownership following synchronous compared to asynchronous stroking. Importantly, no effects of age and no interactions between age and condition were observed for either of these outcome measures. No effects were observed for skin temperature. Overall, these results contribute to an emerging field of research investigating the conditions under which age-related differences in multisensory integration are observed by providing insights into the role of visual, proprioceptive, and tactile inputs on bodily percepts.

scholarly journals Self-body recognition through a mirror: Easing spatial-consistency requirements for rubber hand illusion

2019 ◽  
Author(s):  
Hikaru Hasegawa ◽  
Shogo Okamoto ◽  
Ken Ito ◽  
Masayuki Hara ◽  
Noriaki Kanayama ◽  
...  
Keyword(s):  
Visual Cues ◽  
Mirror Image ◽  
Rubber Hand Illusion ◽  
Body Ownership ◽  
Rubber Hand ◽  
Subjective Evaluations ◽  
Spatial Consistency ◽  
Tactile Stimuli ◽  
Significant Difference ◽  
Body Recognition

AbstractTypical experiments to induce the rubber hand illusion (RHI) require experimental participants to gaze at a fake hand while tactile stimuli are provided to both the fake and hidden actual hands in a synchronous manner. However, under such conditions, postural and apparent disagreement between a seen fake hand and hidden actual hand prevents illusory body ownership. Provided that humans recognize mirror images as copies of the real world in spite of their spatial uncertainties or incongruence, the sensory disagreement may be accepted in RHI settings if using a mirror to show a fake hand. The present study performed two experiments to reveal how self-body recognition of a fake hand feature via mirror affects the RHI. These experiments were conducted in an RHI environment involving voluntary hand movements to investigate not only body ownership but also agency. The first experiment (Experiment 1) examined whether illusory ownership of a fake hand seen in a mirror could be induced. Then, we examined whether the RHI using a mirror image allows disagreement in orientation between the rubber and actual hands (Experiment 2). Subjective evaluations using a RHI questionnaire demonstrated that evoked embodiment of the rubber hand was stronger in the presence of a mirror than in the absence of it (Experiment 1) and that participants experienced the RHI even if the actual and rubber hands were incongruent in terms of orientation (45 °; Experiment 2). No significant difference was found in the change of perceived finger location (proprioceptive drift) between these experiments. These findings suggest that the use of a mirror masks subtle spatial incongruency or degrades the contribution of visual cues for spatial recognition and facilitates multisensory integration for bodily illusions.

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 Embodied Precision: Intranasal Oxytocin Modulates Multisensory Integration

2019 ◽  
Vol 31 (4) ◽  
pp. 592-606 ◽  
Author(s):  
Laura Crucianelli ◽  
Yannis Paloyelis ◽  
Lucia Ricciardi ◽  
Paul M. Jenkinson ◽  
Aikaterini Fotopoulou
Keyword(s):  
Multisensory Integration ◽  
Tactile Stimulation ◽  
Estimation Error ◽  
The Body ◽  
Multisensory Perception ◽  
Subjective Feeling ◽  
Body Ownership ◽  
Rubber Hand ◽  
Perceptual Inference ◽  
Multisensory Input

Multisensory integration processes are fundamental to our sense of self as embodied beings. Bodily illusions, such as the rubber hand illusion (RHI) and the size–weight illusion (SWI), allow us to investigate how the brain resolves conflicting multisensory evidence during perceptual inference in relation to different facets of body representation. In the RHI, synchronous tactile stimulation of a participant's hidden hand and a visible rubber hand creates illusory body ownership; in the SWI, the perceived size of the body can modulate the estimated weight of external objects. According to Bayesian models, such illusions arise as an attempt to explain the causes of multisensory perception and may reflect the attenuation of somatosensory precision, which is required to resolve perceptual hypotheses about conflicting multisensory input. Recent hypotheses propose that the precision of sensorimotor representations is determined by modulators of synaptic gain, like dopamine, acetylcholine, and oxytocin. However, these neuromodulatory hypotheses have not been tested in the context of embodied multisensory integration. The present, double-blind, placebo-controlled, crossover study ( n = 41 healthy volunteers) aimed to investigate the effect of intranasal oxytocin (IN-OT) on multisensory integration processes, tested by means of the RHI and the SWI. Results showed that IN-OT enhanced the subjective feeling of ownership in the RHI, only when synchronous tactile stimulation was involved. Furthermore, IN-OT increased an embodied version of the SWI (quantified as estimation error during a weight estimation task). These findings suggest that oxytocin might modulate processes of visuotactile multisensory integration by increasing the precision of top–down signals against bottom–up sensory input.

The rubber hand illusion and the tactile Simon effect

2012 ◽  
Vol 25 (0) ◽  
pp. 187
Author(s):  
Michael Iannacone ◽  
Jared Medina
Keyword(s):  
Simon Effect ◽  
Body Schema ◽  
Reaction Times ◽  
The Body ◽  
Rubber Hand Illusion ◽  
Hand Position ◽  
Rubber Hand ◽  
Tactile Stimuli ◽  
Experimental Block ◽  
Four Blocks

We examined the effects of the rubber hand illusion on representing tactile stimuli using the Simon effect. In a tactile Simon effect task, participants are instructed to make intensity judgments (using foot pedal responses) to tactile stimuli presented to the hands. Participants are faster when the tactile stimulus and response foot are on the same versus opposite side of the body, regardless of whether the limbs are crossed or uncrossed. Furthermore, participants are faster overall when the hands are crossed versus uncrossed. In this study, participants engaged in a tactile Simon effect experiment with rubber hands positioned directly above the participants’ hidden hands, and with real and rubber hands stroked before each experimental block. Each participant was tested in four blocks, manipulating real and rubber hand position (crossed or uncrossed). First, we found that participants responded faster with real or rubber hands crossed, demonstrating that crossing the hands (real or rubber) can hasten tactile intensity judgments. Furthermore, on trials when the rubber hands were crossed, high ownership ratings for the rubber hand were significantly correlated with faster reaction times. Finally, we found a significantly more robust Simon effect when the rubber hands (but not real hands) were crossed. We discuss these findings with reference to how integration of rubber hands into the body schema influences how we represent the location of tactile stimuli.

scholarly journals What do participants expect to experience in the rubber hand illusion?

2021 ◽  
Author(s):  
Arran T Reader
Keyword(s):  
Subjective Experience ◽  
The Body ◽  
Rubber Hand Illusion ◽  
Body Ownership ◽  
Rubber Hand ◽  
Demand Characteristics ◽  
Open Questions ◽  
Synchronous Condition ◽  
Subjective Reports

The sense of body ownership (the feeling that the body belongs to the self) is commonly believed to arise through multisensory integration. This is famously shown in the rubber hand illusion (RHI), where touches applied synchronously to a false hand and to the participant’s real hand (which is hidden from view) can induce a sensation of ownership over the fake one. Asynchronous touches weaken the illusion, and are typically used as a control condition. Subjective experience during the illusion is measured using a questionnaire, with some statements designed to capture illusory sensation and others designed as controls. However, recent work by Lush (2020, Collabra: Psychology) claimed that participants may have different levels of expectation for questionnaire items in the synchronous condition compared to the asynchronous condition, and for the illusion-related items compared to the control items. This may mean that the classic RHI questionnaire is poorly controlled for demand characteristics. As such, Lush (2020) suggested that subjective reports in the RHI may reflect compliance or even the generation of experience to meet expectations (‘phenomenological control’), rather than multisensory processes underlying the sense of body ownership. In the current work a conceptual replication of Lush (2020) was performed with an improved experimental design. Participants were presented with a video of the RHI procedure and reported the sensations they would expect to experience, both in open questions and by rating questionnaire items. In keeping with Lush (2020), participants had greater expectations for illusion statements in the synchronous condition compared to the asynchronous condition, and for illusion statements compared to control statements. However, there was also evidence that some expectations may be driven by exposure to the questionnaire items rather than exposure to the illusion procedure. The role of pre-illusion expectations and expectations driven by questionnaire exposure in the RHI require further examination.

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