Manipulating sensory and motor cues can cause an illusionary perception of ownership of a fake body part. Presumably, the illusion can work as long as the false body part’s position and appearance are anatomically plausible. Here, we introduce an illusion that challenges past assumptions on body ownership. We used virtual reality to switch and mirror participants’ views of their hands. When a participant moves their physical hand, they see the incongruent virtual hand moving. The result is an anatomically implausible configuration (...) of the fake hand. Despite the hand switch, participants reported significant body ownership sensations over the virtual hands. In the first between-group experiment, we found that the strength of body ownership over the incongruent hands was similar to that of congruent hands. Whereas, in the second within-group experiment, anatomical incongruency significantly decreased body ownership. Still, participants reported significant body ownership sensations of the switched hands. Curiously, we found that perceived levels of agency mediate the effect of anatomical congruency on body ownership. These findings offer a fresh perspective on the relationship between anatomical plausibility and assumed body ownership. We propose that goal-directed and purposeful actions can override anatomical plausibility constraints and discuss this in the context of the immersive properties of virtual reality. (shrink)

The influence of movement skill on action representations and identification of agency was investigated. Point-light displays were created of highly skilled gestures of thirteen orchestral conductors in visual, auditory, and audiovisual versions and compared to two control conditions . In subsequent experimental sessions, participants indicated whether displays presented them or other conductors, whether the soundtrack contained their or others’ musical interpretations, and rated the quality and emotional content of the gestures. Self-recognition was more accurate in conditions presenting highly skilled conducting (...) movements as compared to other displays. Participants judged the quality of their own movements to be better than those of others, independently of whether or not they recognized movement agency. Emotional content was perceived accurately across conditions both for own and others’ actions. These results point to the influence of dynamical characteristics of motor skill, rather than merely type of movement or emotional content, on action representations and self-other identification. (shrink)

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. (shrink)

This article reintroduces a phenomenological experiment designed in the early 1960’s, The Alien-Hand Experiment (TAHE), and it illustrates how phenomena denoted by theoretical concepts like body image, body schema and agency can be studied via the experiment. An analysis of the verbal reports from 26 subjects who participated in TAHE is presented in this article. Subjects were divided into three groups: A group of non-bulimic men, a group of non-bulimic women and a group of female bulimics. The group of (female) (...) bulimics was studied due to the widely spread notion that subjects suffering from eating disorders have a distorted body image. TAHE can be thought of as both a qualitative and quantitative way to study the phenomena arising when the normal relationship between motor behaviour and body experience is disrupted. The present investigation is not an operational definition of body schema and body image, but the two concepts offer a useful interpretive framework. (shrink)

In the present article we discuss the relevance of the mirror mechanism for our sense of self and our sense of others. We argue that, by providing us with an understanding from the inside of actions, the mirror mechanism radically challenges the traditional view of the self and of the others. Indeed, this mechanism not only reveals the common ground on the basis of which we become aware of ourselves as selves distinct from other selves, but also sheds new light (...) on the content of our self and other experience, showing that we primarily experience ourselves and the others in terms of our own and of their motor possibilities respectively. (shrink)

The “body image” is a putative mental representation of one’s own body, including structural and geometric details, as well as the more familiar visual and affective aspects. Very little research has investigated how we learn the structure of our own body, with most researchers emphasising the canonical visual representation of the body when we look at ourselves in a mirror. Here, we used non-visual self-touch in healthy participants to investigate the possibility that primary sensorimotor experience may influence cognitive representations of (...) one’s own body structure. Participants used the fingers of one hand , to touch the fingers of the other . A conflict between the experience of the active and passive hand was introduced by experimenter interleaving their fingers with the fingers of the participant’s passive hand. This led to the active hand experiencing that it touched more fingers than the passive hand felt it was being touched by. The effects on representation of body structure were assessed using an implicit measure based on Kinsbourne and Warrington’s ‘in-between task’. We found an underestimation of the number of fingers in the central part of the hand specifically linked to the experience of self-touch. This pattern of results corresponds to the experience of the passive hand, but not the active hand. Nevertheless, comparable reorganisation of fingers within the hand representation was found for both active and passive hands. We show that primary sensorimotor experience can modify the representation of body structure. This modification is driven by the passive experience of being touched, rather than by the active experience of touching. We believe this is the first experimental study of effects of self-touch on the mental representation of the body. (shrink)

Self–other discrimination was investigated with point-light displays in which actions were presented with or without additional auditory information. Participants first executed different actions in time with music. In two subsequent experiments, they watched point-light displays of their own or another participant’s recorded actions, and were asked to identify the agent . Manipulations were applied to the visual information and to the auditory information . Results indicate that self-recognition was better than chance in all conditions and was highest when observing relatively (...) unconstrained patterns of movement. Auditory information did not increase accuracy even with the most ambiguous visual displays, suggesting that judgments of agent identity depend much more on motor cues than on auditory or audiovisual information. (shrink)

I put forward an externalist theory of social understanding. On this view, psychological sense making takes place in environments that contain both agent and interpreter. The spatial structure of such environments is social, in the sense that its occupants locate its objects by an exercise in triangulation relative to each of their standpoints. This triangulation is achieved in intersubjective interaction and gives rise to a triadic model of the social mind. This model can then be used to make sense of (...) others’ observed actions. Its possession plays a vital role in the development of the capacity for false belief reasoning. The view offers an integrated account of the development of social cognition from primary intersubjectivity to level-2 perspective taking. It incorporates insights from interactionism and mindreading theories of social cognition and thus offers a way out of the stalemate between defenders of the two views. Because psychological sense making is perspectival, the frame problem does not arise for social reasoners: the perspective they bring to bear on the action that is to be interpreted constrains the information they can select to make sense of what others do. (shrink)

I put forward an externalist theory of social understanding. On this view, psychological sense making takes place in environments that contain both agent and interpreter. The spatial structure of such environments is social, in the sense that its occupants locate its objects by an exercise in triangulation relative to each of their standpoints. This triangulation is achieved in intersubjective interaction and gives rise to a triadic model of the social mind. This model can then be used to make sense of (...) others’ observed actions. Its possession plays a vital role in the development of the capacity for false belief reasoning. The view offers an integrated account of the development of social cognition from primary intersubjectivity to level-2 perspective taking. It incorporates insights from interactionism and mindreading theories of social cognition and thus offers a way out of the stalemate between defenders of the two views. Because psychological sense making is perspectival, the frame problem does not arise for social reasoners: the perspective they bring to bear on the action that is to be interpreted constrains the information they can select to make sense of what others do. (shrink)

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. (shrink)

The ability to distinguish between our own actions and those of an external agent is a fundamental component of normal human social interaction. Both low- and high-level mechanisms are thought to contribute to the sense of movement agency, but the contribution of each is yet to be fully understood. By applying small and incremental perturbations to realistic visual feedback of the limb, the influence of high-level action intentions and low-level motor predictive mechanisms were dissociated in two experiments. In the first, (...) participants were induced to claim agency over movements that were subject to large perturbations and to deny agency over self-produced unperturbed movements despite the application of motor corrections by low-level mechanisms. A control experiment confirmed that if reaches met with their intended goal then they were more likely to be attributed to the agent, regardless of the discrepancy between the actual and seen positions of the limb. (shrink)

We are perceivers, we are thinkers, and we are also agents, bringing about physical events, such as bodily movements and their consequences. What we do tells us, and others, a lot about who we are. On the one hand, who we are determines what we do. On the other hand, acting is also a process of self-discovery and self-shaping. Pivotal to this mutual shaping of self and agency is the sense of agency, or agentive self-awareness, i.e., the sense that one (...) is the agent of an action. (shrink)

Current models of delusion converge in proposing that delusional beliefs are based on unusual experiences of various kinds. For example, it is argued that the Capgras delusion (the belief that a known person has been replaced by an impostor) is triggered by an abnormal affective experience in response to seeing a known person; loss of the affective response to a familiar person’s face may lead to the belief that the person has been replaced by an impostor (Ellis & Young, 1990). (...) Similarly, the Cotard delusion (which involves the belief that one is dead or unreal in some way) may stem from a general.. (shrink)

The recent distinction between sense of agency and sense of body-ownership has attracted considerable empirical and theoretical interest. The respective contributions of central motor signals and peripheral afferent signals to these two varieties of body experience remain unknown. In the present review, we consider the methodological problems encountered in the empirical study of agency and body-ownership, and we then present a series of experiments that study the interplay between motor and sensory information. In particular, we focus on how multisensory signals (...) interact with body representations to generate the sense of body-ownership, and how the sense of agency modulates the sense of body-ownership. Finally, we consider the respective roles of efferent and afferent signals for the experience of one’s own body and actions, in relation to self-recognition and the recognition of other people’s actions. We suggest that the coherent experience of the body depends on the integration of efferent information with afferent information in action contexts. Overall, whereas afferent signals provide the distinctive content of one’s own body experience, efferent signals seem to structure the experience of one’s own body in an integrative and coherent way. (shrink)

The self seems to be a unitary entity remaining stable across time. Nevertheless, current theorizing conceptualizes the self as a number of interacting sub-systems involving perception, intention and action (self-model). One important function of such a self-model is to distinguish between events occurring as a result of one's own actions and events occurring as the result of somebody else's actions. We conducted an fMRI experiment that compared brain activation after an abrupt mismatch between one's own movement and its visual consequences (...) with an abrupt mismatch between one's own movement and somebody else's visually perceived hand movement. A right fronto-parietal network was selectively active during a sudden mismatch between one's own observed and performed hand action. (shrink)

This paper is concerned with the problem of selfidentification in the domain of action. We claim that this problem can arise not just for the self as object, but also for the self as subject in the ascription of agency. We discuss and evaluate some proposals concerning the mechanisms involved in selfidentification and in agencyascription, and their possible impairments in pathological cases. We argue in favor of a simulation hypothesis that claims that actions, whether overt or covert, are centrally simulated (...) by the neural network, and that this simulation provides the basis for action recognition and attribution. (shrink)

A dominant view in contemporary cognitive neuroscience is that low-level, comparator-based mechanisms of motor control produce a distinctive experience often called the feeling of agency . An opposing view is that comparator-based motor control is largely non-conscious and not associated with any particular type of distinctive phenomenology . In this paper, I critically evaluate the nature of the empirical evidence researchers commonly take to support FoA-hypothesis. The aim of this paper is not only to scrutinize the FoA-hypothesis and data supposed (...) to support it; it is equally to argue that experimentalists supporting the FoA-hypothesis fail to establish that the experimental outcomes are more probable given the FoA-hypothesis than given the simpler hypothesis. (shrink)

Our understanding of body ownership largely relies on the Rubber Hand Illusion (RHI) paradigm where synchronous stroking of the real and fake hands leads to an illusion of ownership of RH provided its physical, anatomical, and spatial plausibility. Self-attribution of a fake hand also occurs during visuomotor synchrony, when the visual feedback of self-initiated movements follows the trajectory of the instantiated motor command. In both cases, the experience of ownership is established through bottom-up integration and top-down prediction of multisensory (proximodistal) (...) cues within the peripersonal space. It seems, however, that depending on whether the signals are externally or self-generated, top-down expectation signals are qualitatively different. On the one hand, in RHI, the sensory correlations are modulated by empirically induced priors about the internal model of the body. On the other hand, in mRHI, body ownership is actively shaped by processes allowing for continuous comparison between the actual and predicted sensory consequences of the actions. Ample research demonstrates that the differential processing of the predicted and the actual reafferent information is addressed by the central nervous system via an internal Forward Model (FM). Indeed, results from mRHI suggest that in action-contexts mechanism underlying body ownership could be similar to the FM. Crucially FMs integrate across all sensory input including not only proximodistal (visuomotor) but also purely distal sensory signals (visuoauditory). Thus if body ownership results from a consistency of FM, it would be affected by the (in)congruency of purely distal signals provided that they inform about the action-consequences relevant to the task. Here we explicitly address this question. To test our hypothesis, we devise an embodied VR-based task where action outcomes were signaled by distinct auditory cues. By manipulating the cues with respect to their spatial, temporal and semantic congruency, we show that purely distal feedback violating predictions about action outcomes compromises both body ownership and performance. These results demonstrate that body ownership is influenced by cues which not only pertain to the body itself but also those arising outside of the body, and suggest that in goal-oriented tasks body ownership might result from the consistency of forward models. (shrink)

Schizophrenia spectrum has been associated with a disruption of the basic sense of self, which pertains, among others, the representation of one’s own body. We investigated the impact of either implicit or explicit access to the representation of one’s own body-effectors on bodily self-awareness, in first-episode schizophrenia patients and healthy controls . We contrasted their performance in an implicit self-recognition task and in an explicit self/other discrimination task. Both tasks employed participant’s own and others’ body-effectors. Concerning the implicit task, HCs (...) were more accurate with their own than with others’ body-effectors, whereas patients did not show such self-advantage. Regarding the explicit task, both groups did not exhibit a self-advantage, and patients showed a higher percentage of self-misattribution errors. Neither self/other nor implicit/explicit effects were found in both groups when processing inanimate-objects. We propose that FES patients suffer of a disturbed implicit sense of bodily self. (shrink)

The sense of agency is a basic feature of our subjective experience. Experimental studies usually focus on either its attributional aspects or on its motoric aspects. Here, we combine both aspects and focus on the subjective experience of the time between action and effect. Previous studies [Haggard, P., Aschersleben, G., Gehrke, J., & Prinz, W.. Action, binding and awareness. In W. Prinz, & B. Hommel, Common mechanisms in perception and action: Attention and performance. Oxford: Oxford University Press] have shown a (...) temporal attraction in the perceived times of actions and effects, but did directly not study the relation between them. In three experiments, time estimates of an interval between an action and its subsequent sensory effect were obtained. The actions were either voluntary key press actions performed by the participant or kinematically identical movements applied passively to the finger. The effects were either auditory or visual events or a passive movement induced to another finger. The results first indicated a shortening of the interval between one’s own voluntary action and a subsequent effect, relative to passive movement conditions. Second, intervals initiated by observed movements, either of another person or of an inanimate object, were always perceived like those involving passive movements of one’s own body, and never like those involving active movements. Third, this binding effect was comparable for auditory, somatic and visual effects of action. Our results provide the first direct evidence that agency involves a generalisable relation between actions and their consequences, and is triggered by efferent motor commands. (shrink)

The sense of agency is the experience of being the origin of a sensory consequence. This study investigates whether contextual beliefs modulate low-level sensorimotor processes which contribute to the emergence of the sense of agency. We looked at the influence of causal beliefs on ‘intentional binding’, a phenomenon which accompanies self-agency. Participants judged the onset-time of either an action or a sound which followed the action. They were induced to believe that the tone was either triggered by themselves or by (...) somebody else, although, in reality, the sound was always triggered by the participants. We found that intentional binding was stronger when participants believed that they triggered the tone, compared to when they believed that another person triggered the tone. These results suggest that high-level contextual information influences sensorimotor processes responsible for generating intentional binding. (shrink)

I compare Frith and colleagues’ influential comparator account of how the sense of agency is elicited to the multifactorial weighting model advocated by Synofzik and colleagues. I defend the comparator model from the common objection that the actual sensory consequences of action are not needed to elicit the sense of agency. I examine the comparator model’s ability to explain the performance of healthy subjects and those suffering from delusions of alien control on various self-attribution tasks. It transpires that the comparator (...) model needs case-by-case adjustment to deal with problematic data. In response to this, the multifactorial weighting model of Synofzik and colleagues is introduced. Although this model is incomplete, it is more naturally constrained by the cases that are problematic for the comparator model. However, this model may be untestable. I conclude that currently the comparator model approach has stronger support than the multifactorial weighting model approach. (shrink)

In normal observers, gazing at one’s own face in the mirror for a few minutes, at a low illumination level, triggers the perception of strange faces, a new visual illusion that has been named ‘strange-face in the mirror’. Individuals see huge distortions of their own faces, but they often see monstrous beings, archetypal faces, faces of relatives and deceased, and animals. In the experiment described here, strange-face illusions were perceived when two individuals, in a dimly lit room, gazed at each (...) other in the face. Inter-subjective gazing compared to mirror-gazing produced a higher number of different strange-faces. Inter-subjective strange-face illusions were always dissociative of the subject’s self and supported moderate feeling of their reality, indicating a temporary lost of self-agency. Unconscious synchronization of event-related responses to illusions was found between members in some pairs. Synchrony of illusions may indicate that unconscious response–coordination is caused by the illusion–conjunction of crossed dissociative strange-faces, which are perceived as projections into each other’s visual face of reciprocal embodied representations within the pair. Inter-subjective strange-face illusions may be explained by the subject’s embodied representations and the other’s visual face binding. Unconscious facial mimicry may promote inter-subjective illusion–conjunction, then unconscious joint-action and response–coordination. (shrink)

There are few concepts as relevant as that of intentional action in shaping our sense of self and the interaction with the environment. At the same time, few concepts are so elusive. Indeed, both conceptual and neuroscientific accounts of intentional agency have proven to be problematic. On the one hand, most conceptual views struggle in defining how agents can adequately exert control over their actions. On the other hand, neuroscience settles for definitions by exclusion whereby key features of human intentional (...) actions, including goal-directness, remain underspecified. This paper reviews the existing literature and sketches how this gap might be filled. In particular, we defend a gradualist notion of intentional behaviour, which revolves around the following key features: autonomy, flexibility in the integration of causal vectors, and control. (shrink)

The goal of this study is to characterize observers’ abilities to discriminate between endogenous and exogenous changes. To do so, we developed a new experimental paradigm. On each trial, participants were shown a dot pattern on the screen. Next, the pattern disappeared and participants were to reproduce it. Changes were surreptuously introduced in the stimulus, either by presenting participants anew with the dot pattern they had themselves produced on the previous trial or by presenting participants with a slightly different dot (...) pattern . We analyzed awareness of the changes and behavioral adaptation to them in a dynamical manner. We observe signal attenuation in the presence of endogenous change, dissociation between self-attribution reports and behavioral effect of agency. We discuss the source of this sensitive attenuation as well as the relation between a minimal or core self and an extended, narrative or autobiographical self. (shrink)

This chapter aims at investigating the phenomenology of joint action and at gaining a better understanding of (1) how the sense of agency one experiences when engaged in a joint action differs from the sense of agency one has for individual actions and (2) how the sense of agency one experiences when engaged in a joint action differs according to the type of joint action and to the role one plays in it.