scholarly journals Bodily ownership of an independent supernumerary limb: An exploratory study

2021 ◽  
Author(s):  
Kohei Umezawa ◽  
Yuta Suzuki ◽  
Gowrishankar Ganesh ◽  
Yoichi Miyawaki
Keyword(s):  
Human Brain ◽  
Sensory Feedback ◽  
Body Representation ◽  
The Body ◽  
Artificial Limbs ◽  
Cognitive Measures ◽  
Rubber Hand ◽  
Artificial Limb ◽  
Sense Of Ownership ◽  
Induced Changes

AbstractCan our brain perceive a sense of ownership towards an independent supernumerary limb; one that can be moved independently of any other limb and provides its own independent movement feedback? Following the rubberhand illusion experiment, a plethora of studies has shown that the human representation of ‘self’ is very plastic. But previous studies have almost exclusively investigated ownership towards ‘substitute’ artificial limbs, which are controlled by the movements of a real limb and/or limbs from which non-visual sensory feedback is provided on an existing limb. Here, to investigate whether the human brain can own an independent artificial limb, we first developed a novel independent robotic ‘sixth finger.’ We allowed participants to train using the finger and examined whether it induced changes in the body representation using behavioral as well as cognitive measures. Our results suggest that unlike a substituted artificial limb (like in the rubber hand experiment), it is more difficult for humans to perceive a sense of ownership towards an independent limb. However, ownership does seem possible, as we observed clear tendencies of changes in the body representation that correlated with the cognitive reports of the sense of ownership. Our results provide the first evidence to show that an independent supernumerary limb can be embodied by the human brain.

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.

scholarly journals Rubber Hand Illusion does not arise from comparisons with internal body models: a new multisensory integration account of the sense of ownership

2018 ◽  
Author(s):  
Piotr Litwin
Keyword(s):  
Multisensory Integration ◽  
Human Body ◽  
The Body ◽  
Rubber Hand Illusion ◽  
Multisensory Perception ◽  
Top Down ◽  
Rubber Hand ◽  
Sense Of Ownership ◽  
Body Model ◽  
Internal Body

Human body sense is surprisingly flexible – precisely administered multisensory stimulation may result in the illusion that an external object is part of one’s body. There seems to be a general consensus that there are certain top-down constraints on which objects may be incorporated: in particular, to-be-embodied objects should be structurally similar to a visual representation stored in an internal body model for a shift in one’s body image to occur. However, empirical evidence contradicts the body model hypothesis: the sense of ownership may be spread over objects strikingly distinct in morphology and structure (e.g., robotic arms or empty space) and direct empirical support for the theory is currently lacking. As an alternative, based on the example of the rubber hand illusion (RHI), I propose a multisensory integration account of how the sense of ownership is induced. In this account, the perception of one’s own body is a regular type of multisensory perception and multisensory integration processes are not only necessary but also sufficient for embodiment. In this paper, I propose how RHI can be modeled with the use of Maximum Likelihood Estimation and natural correlation rules. I also discuss how Bayesian Coupling Priors and idiosyncrasies in sensory processing render prior distributions interindividually variable, accounting for large interindividual differences in susceptibility to RHI. Taken together, the proposed model accounts for exceptional malleability of human body perception, fortifies existing bottom-up multisensory integration theories with top-down models of relatedness of sensory cues, and generates testable and disambiguating predictions.

scholarly journals How to lose a hand: Sensory updating drives disembodiment

2020 ◽  
Author(s):  
Roland Pfister ◽  
Annika L. Klaffehn ◽  
Andreas Kalckert ◽  
Wilfried Kunde ◽  
David Dignath
Keyword(s):  
Multisensory Integration ◽  
Body Representation ◽  
The Body ◽  
Rubber Hand ◽  
Body Representations ◽  
Dynamic View ◽  
Single Instance ◽  
Multisensory Input ◽  
To Receive ◽  
Real Hand

AbstractBody representations are readily expanded based on sensorimotor experience. A dynamic view of body representations, however, holds that these representations cannot only be expanded but that they can also be narrowed down by disembodying elements of the body representation that are no longer warranted. Here we induced illusory ownership in terms of a moving rubber hand illusion and studied the maintenance of this illusion across different conditions. We observed ownership experience to decrease gradually unless participants continued to receive confirmatory multisensory input. Moreover, a single instance of multisensory mismatch – a hammer striking the rubber hand but not the real hand – triggered substantial and immediate disembodiment. Together, these findings support and extend previous theoretical efforts to model body representations through basic mechanisms of multisensory integration. They further support an updating model suggesting that embodied entities fade from the body representation if they are not refreshed continuously.

scholarly journals Seeing the whole man: a visualist analysis of artificial limbs at the end of the nineteenth century

2021 ◽  
Author(s):  
Constance Crompton
Keyword(s):  
Nineteenth Century ◽  
Discourse Analysis ◽  
Visual Culture ◽  
Critical Discourse Analysis ◽  
The Body ◽  
Critical Discourse ◽  
Artificial Limbs ◽  
Artificial Limb ◽  
Culture Studies ◽  
Visual Culture Studies

The thesis uses the central concerns of visual culture studies to investigate the shift towards artificial limbs that imitate the body as identified by Steven Mihm (2002). Drawing on a modified, less utopian, form of critical discourse analysis, which recognizes the sociocultural power of the visual, this thesis interrogates the promotional literature that the A.A. Marks Company, an artificial limb manufacturer, produced between 1888 and 1920. This thesis critically analyzes the techniques used by the company to assert their authority to frame their relationship to their clients. In addition, this analysis interrogates the company's use of the technologies of vision to champion visually imitative prosthesis. The goal of this analysis is to determine how the company deployed the turn towards the imitative, and what was at stake for the producers, and consumers, as well as the wider culture in the use of imitative limbs.

Architectural Affordances

2021 ◽  
pp. 230-234
Author(s):  
Zakaria Djebbara ◽  
Klaus Gramann
Keyword(s):  
Built Environment ◽  
Human Brain ◽  
Action Potentials ◽  
Sensory Feedback ◽  
Aesthetic Experience ◽  
Functional Relation ◽  
Human Experience ◽  
The Body ◽  
Action And Perception ◽  
The Brain

In the article discussed in this chapter, the authors describe a framework of neuroaesthetics for architectural experiences that considers sensory feedback stemming from movement central for the experience of the built environment. As we move through space when experiencing architecture, our sensory impressions change, rendering the body and the brain as nondissociable agents of aesthetic experience. This interaction is described by the term affordance. The authors cast the human experience of the built environment to be predicated on the functional relation between action and perception and developed a neuroscientific experiment on architectural transitions to investigate how the human brain reflects architectural affordances. They found that varying sizes of transitions, reflecting different affordances, impact early perceptual processes, suggesting that our perception is indeed colored by the action potentials afforded by the composed space. In conclusion, the shape of space resonates with our embodied predictions regarding movement.

Ownership and the Space of the Body

2018 ◽  
Author(s):  
José Luis Bermúdez
Keyword(s):  
Cognitive Science ◽  
The Body ◽  
Rubber Hand Illusion ◽  
Main Body ◽  
Experimental Paradigm ◽  
Rubber Hand ◽  
Bodily Experience ◽  
Sense Of Ownership ◽  
The Third ◽  
Body Section

In the last 20 years, a robust experimental paradigm has emerged for studying the structure of bodily experience, focusing primarily on what it is to experience one’s body as one’s own. The initial impetus came from the rubber hand illusion (RHI) first demonstrated by Botvinick and Cohen, subsequently extended by various researchers to generate illusions of ownership at the level of the body as a whole. This paper identifies some problems with how ownership is discussed in the context of bodily illusions, and then shows how those problems can be addressed through a model of the experienced space of the body. Section 1 briefly reviews the bodily illusions literature and its significance for cognitive science and philosophy. Section 2 expresses reservations with the concept of ownership in terms of which the RHI and other illusions are standardly framed. I offer three hypotheses for the source of our putative “sense of ownership”. The main body of the paper focuses on the third hypothesis, which is that judgments of ownership are grounded in the distinctive way that we experience the space of the body.

The Bodyguard Hypothesis

2017 ◽  
Author(s):  
Frédérique de Vignemont
Keyword(s):  
The Body ◽  
Sense Of Agency ◽  
Special Significance ◽  
Rubber Hand ◽  
Sense Of Ownership ◽  
Body Map ◽  
Self Defence

How are the sense of ownership and the sense of agency related? Does one need to be able to control one’s body to experience it as one’s own? One may suggest that the sense of bodily ownership is grounded in action-orientated representations of the body. However, this agentive hypothesis cannot explain how one can experience as one’s own a rubber hand that is not under control, while not experiencing as one’s own tools that are under control. The chapter then argues that one needs to distinguish between two kinds of hot body maps: the working body map involved in instrumental actions, and the protective body map involved in self-defence. It is proposed that one experiences as one’s own the body represented in the protective body map, which represents the body that has a special significance for the evolutionary needs of the organism.

The role of hand size in own-body representation in childhood, adolescence & adulthood

2021 ◽  
Author(s):  
Janna M. Gottwald ◽  
Laura Bird ◽  
Andrew J. Bremner ◽  
Dorothy Cowie
Keyword(s):  
Age Groups ◽  
Body Schema ◽  
Body Representation ◽  
The Body ◽  
Size Change ◽  
Rubber Hand ◽  
Hand Size ◽  
Multisensory Information ◽  
Proprioceptive Drift

Children’s and adults’ body representation is constrained by bottom-up multisensory information and by top-down knowledge on possible postures. Using the rubber hand illusion paradigm, this study (N = 229) investigates whether different fake hand sizes (60%, 80%, 100%, 120% or 140% of typical hand size) constrain embodiment in three age groups (6- to 7-year-olds, 12- to 13-year-olds, and adults). Embodiment was measured by questionnaire, proprioceptive drift, and affordance judgements. In line with previous work, we found robust effects of age and synchrony, with higher responses at younger ages and under conditions of visual-tactile synchrony. There were no significant effects of hand size on proprioceptive drift or self-rated hand ownership; nor did participants verbally report that their hand had changed size. Participants of all ages therefore embodied a differently-sized fake hand, without being explicitly aware of the size change. However, manual judgments of own-hand size were significantly influenced by the size of the previously seen fake hand. Therefore, participants did implicitly incorporate a size change into their body schema. In sum, embodiment of differently-sized hands reveals substantial plasticity in body representation, modulated strongly by multisensory information and age. Further, the embodiment of a differently-sized hand specifically affects action-oriented representations of the body.

scholarly journals Seeing the whole man: a visualist analysis of artificial limbs at the end of the nineteenth century

2021 ◽  
Author(s):  
Constance Crompton
Keyword(s):  
Nineteenth Century ◽  
Discourse Analysis ◽  
Visual Culture ◽  
Critical Discourse Analysis ◽  
The Body ◽  
Critical Discourse ◽  
Artificial Limbs ◽  
Artificial Limb ◽  
Culture Studies ◽  
Visual Culture Studies

The thesis uses the central concerns of visual culture studies to investigate the shift towards artificial limbs that imitate the body as identified by Steven Mihm (2002). Drawing on a modified, less utopian, form of critical discourse analysis, which recognizes the sociocultural power of the visual, this thesis interrogates the promotional literature that the A.A. Marks Company, an artificial limb manufacturer, produced between 1888 and 1920. This thesis critically analyzes the techniques used by the company to assert their authority to frame their relationship to their clients. In addition, this analysis interrogates the company's use of the technologies of vision to champion visually imitative prosthesis. The goal of this analysis is to determine how the company deployed the turn towards the imitative, and what was at stake for the producers, and consumers, as well as the wider culture in the use of imitative limbs.

scholarly journals Rubber Hand Illusion does not arise from comparisons with internal body models: a new multisensory integration account of the sense of ownership

2018 ◽  
Author(s):  
Piotr Litwin
Keyword(s):  
Multisensory Integration ◽  
Human Body ◽  
The Body ◽  
Rubber Hand Illusion ◽  
Multisensory Perception ◽  
Top Down ◽  
Rubber Hand ◽  
Sense Of Ownership ◽  
Body Model ◽  
Internal Body

Human body sense is surprisingly flexible – precisely administered multisensory stimulation may result in the illusion that an external object is part of one’s body. There seems to be a general consensus that there are certain top-down constraints on which objects may be incorporated: in particular, to-be-embodied objects should be structurally similar to a visual representation stored in an internal body model for a shift in one’s body image to occur. However, empirical evidence contradicts the body model hypothesis: the sense of ownership may be spread over objects strikingly distinct in morphology and structure (e.g., robotic arms or empty space) and direct empirical support for the theory is currently lacking. As an alternative, based on the example of the rubber hand illusion (RHI), I propose a multisensory integration account of how the sense of ownership is induced. In this account, the perception of one’s own body is a regular type of multisensory perception and multisensory integration processes are not only necessary but also sufficient for embodiment. In this paper, I propose how RHI can be modeled with the use of Maximum Likelihood Estimation and natural correlation rules. I also discuss how Bayesian Coupling Priors and idiosyncrasies in sensory processing render prior distributions interindividually variable, accounting for large interindividual differences in susceptibility to RHI. Taken together, the proposed model accounts for exceptional malleability of human body perception, fortifies existing bottom-up multisensory integration theories with top-down models of relatedness of sensory cues, and generates testable and disambiguating predictions.

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