Sense of Embodiment

Man, even though he may sometimes dream of being a pure spirit free from all material constraints, actually exists as a body in a world which is itself essentially constructed as a spatialized system of bodies; and in this constructed world features such as resistance, impenetrability, inertia, weight and forces are not accidents or exceptions but the rule.
The reflexions presented in this work aim at elucidating on a phenomenological level the relation that man entertains with the tangible aspects of his environment, and the function that this relation plays in the construction of the different sectors of his existence. The first of the sectors is perception: the opening on an ambient world that is pregnant with organisation and meaning. On the one hand, we shall take into account and conceptualize the way in which the tangibility of the world (the testing experience that the individual can have of resistance of his environment in the frame of a direct bodily relation with that environment, but more generally the understanding that the individual possesses of the very possibility of such a relation) participates in setting up the rationality by which man renders his world intelligible. On the other hand, we shall identify the structures of “subjectivity” (to speak the language of psychology, the structures of cognition) which make possible the specific way in which man constructs his experience and understanding of tangible resistance – whether this resistance is perceived in the context of an actual bodily engagement, or whether it is envisaged “indirectly” in the guise of a “simple” possibility.
We shall show here, on the basis of phenomenological analyses as well as elements coming from empirical psychology (experimental psychology as well as neuropsychology), that the relation that man has with the resistance of his ambient world depends on an opening towards the possible; and that the organisation of the ambient world in the form of a space which can contain material structures, or structures capable of opposing a resistance to the body, depends on a rationality which consists of making phenomena intelligible by interpreting them with reference to those capacities for action and for passion which the body confers on us, to the power that the body provides us with and the constraints to which it submits us.
Thus, even though the realm of material things – tangible objects, bodies – functions as an archetype of “presence” and of “being” (indeed, what is more “real” than a body?), in the last resort it gains its phenomenal character from the fact that it crystallizes for the person who perceives it a stream of virtual possibilities; hence, the here-and-now presence of the “tangible world” is in an essential way indebted to the realm of that which is not actually realized.

The sense of embodiment is vital for self recognition. An examination of anosognosia for hemiplegia—the inability to recognise that one is paralysed down one side of one’s body—suggests the existence of ‘online’ and ‘offline’ representations of the body. Online representations of the body are representations of the body as it is currently, are newly constructed moment by moment and are directly ‘‘plugged into” current perception of the body. In contrast, offline representations of the body are representations of what the body is usually like, are relatively stable and are constructed from online representations. This distinction is supported by an analysis of phantom limb—the feeling that an amputated limb is still present—phenomena. Initially it seems that the sense of embodiment may arise from either of these types of representation; however, an integrated representation of the body seems to be required. It is suggested information from vision and emotions is involved in generating these representations. A lack of access to online representations of the body does not necessarily lead to a loss in the sense of embodiment. An integrated offline representation of the body could account for the sense of embodiment and perform the functions attributed to this sense.

Recent findings from studies of epileptic patients and schizotypes have suggested that disruptions in multi-sensory integration processes may underlie a predisposition to report out-of-body experiences (OBEs: Blanke et al., 2004; Mohr et al., 2006). It has been argued that these disruptions lead to a breakdown in own-body processing and embodiment. Here we present two studies which provide the first investigation of predisposition to OBEs in the normal population as measured primarily by the recently devised Cardiff anomalous perception scale (CAPS; Bell et al., 2006). The Launay-Slade Hallucination scale (LSHS) was also employed to provide a measure of general hallucination proneness. In Study 1, 63 University students participated in the study, 17 of whom (26%) claimed to have experienced at least one OBE in their lifetime. OBEers reported significantly more perceptually anomalies (elevated CAPS scores) but these were primarily associated with specific measures of temporal-lobe instability and body-distortion processing. Study 2 demonstrated that OBEers and those scoring high on measures of temporal-lobe instability/body-distortion processing were significantly impaired, relative to controls, at a task requiring mental own-body transformations (OBTs) (Blanke et al., 2005). These results extend the findings from epileptic patient studies to the psychologically normal population and are consistent with there being a disruption in temporal-lobe and body-based processing underlying OBE-type experiences.

De Vignemont argues that the sense of ownership comes from the localization of bodily sensation on a map of the body that is part of the body schema. This model should be taken as a model of the sense of embodiment. I argue that the body schema lacks the theoretical resources needed to explain this phenomenology. Furthermore, there is some reason to think that a deficient sense of embodiment is not associated with a deficient body schema. The data de Vignemont uses to argue that the body image does not underlie the sense of embodiment does not rule out the possibility that part of the body image I call ‘offline representations’ underlies the sense of embodiment. An alternative model of the sense of embodiment in terms of offline representations of the body is presented.

... Issue Date: 2008. ISSN: 1053-8100. School/Discipline: School of Humanities : Philosophy. Statement of Responsibility: Glenn Carruthers. RMID: 0020083893. DOI: 10.1016/j.concog. 2008.07.008. Links to content (authorised users): Check full text options. ...

The experience of embodiment may be studied using the rubber hand illusion. Little is known about the cognitive mechanism that elicits the feeling of embodiment. In previous models of the rubber hand illusion, bodily signals are processed sequentially. Such models cannot explain some more recent findings. Carruthers (2013) proposed a multidimensional model of embodiment, in which the processing of embodiment is understood in terms of conceptual hand space. Visual features of hands are represented along several dimensions. The rubber hand illusion is then explained as the erroneous matching of the online representation of the artificial hand to the stored prototype in a space defined by those dimensions. We conducted the first experimental tests to investigate the multidimensional conceptual space account. First, participants performed a series of odd-one-out judgments for triads of hand images (including their own hand) and we then employed multidimensional scaling analyses. We found that a multidimensional model of perceived hand similarity could be fitted to our data. Second, we tested if a multisensory bodily signal manipulation (the rubber hand illusion) influences the position of the viewed artificial hand in hand space. We employed synchronous and asynchronous stroking and found that in the synchronous condition, which elicits the rubber hand illusion, compared to the asynchronous condition, which does not, the artificial hand was closer to the center of hand space; that is, to a prototype hand. We discuss these findings in the context of the Carruthers (2013) conceptual space model as well as other rubber hand illusion models.

This book proposes a novel and rigorous explanation of consciousness. It argues that the study of an aspect of our self-consciousness known as the ‘feeling of embodiment’ teaches us that there are two distinct phenomena to be targeted by an explanation of consciousness. First is an explanation of the phenomenal qualities – 'what it is like' – of the experience; and second is the subject's awareness of those qualities. Glenn Carruthers explores the phenomenal qualities of the feeling of embodiment using the tools of quality spaces, as well as the subject's awareness of those qualities as a functionally emergent property of various kinds of processing of these spaces. Where much recent work on consciousness focuses on visual experience, this book rather draws evidence from the study of self-consciousness.
Carruthers argues that in light of recent methodological discoveries, awareness must be explained in terms of the organization of multiple cognitive processes. The book offers an explanation of anomalous body representations and, from that, poses a more general theory of consciousness. Ultimately this book creates a hybrid account of consciousness that explains phenomenology and awareness using different tools. It will be of great interest to all scholars of psychology and philosophy as well as anyone interested in exploring the intricacies of how we experience our bodies, what we are and how we fit into the world.

I thank Tsakiris and Fotopoulou for their insightful commentary on my target article. In particular I welcome the opportunity to revisit how the online/offline representation of the body distinction is drawn. Tsakiris and Fotopoulou raise three major points of concern with my model. First they argue that the sense of embodiment is not sufficient for self recognition. Second they show that the relationship between online and offline representations of the body cannot be the simple ‘serial construction’ relationship I advocate in the target article. Third they claim that my model makes a false prediction. I agree with the first two lines of criticism. As to the first I will clarify and tone down the claims made about the role of the sense of embodiment in self recognition tasks. However, I will argue that the sense of embodiment is measured in van den Bos and Jeannerod’s study. I strongly welcome the second line of criticism Tsakiris and Fotopoulou offer. I will add some reasons to agree that the ‘serial construction’ account of the relationship between online and offline representations cannot be true. I maintain, however, that this does not affect the central thesis of target article, namely that it is an offline representation of the body that underlies the sense of embodiment. Finally, I will defend the model by arguing that it does not make the false prediction Tsakiris and Fotopoulou attribute to it.