Ambiguous Body Ownership Experience Caused by Feeling–judgement Conflict: Evidence from Subjective Measurement in Rubber Hand Illusion using Integrated Information Theory

Human body awareness is malleable and adaptive to changing contexts. The illusory sense of body-ownership has been studied since the publication of the rubber hand illusion, where ambiguous body ownership feeling, expressed as "the dummy hand is my hand even though that is not true", was first defined. Phenomenologically, the ambiguous body ownership is attributed to a conflict between feeling and judgement; in other words, it characterises a discrepancy between first-person (i.e. bottom-up) and third-person (i.e. top-down) processes. Although Bayesian inference can explain this malleability of body image sufficiently, the theory does not provide a good illustration of why we have different experiences to the same stimuli -- the difficulty lies in the uncertainty regarding the concept of judgement in their theory. This study attempts to explain subjective experience during rubber hand illusions using integrated information theory (IIT). The integrated information Φ in IIT measures the difference between the entire system and its subsystems. This concept agrees with the phenomenological interpretation -- that is, there is conflict between judgement and feeling. By analysing the seven nodes of a small body--brain system, we demonstrate that the integrity of the entire system during the illusion decreases with increasing integrity of its subsystems. These general tendencies agree well with many brain-image analyses and subjective reports; furthermore, we found that subjective ratings were associated with the Φs. Our result suggests that IIT can explain the general tendency of the sense of ownership illusions and individual differences in subjective experience during the illusions.

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Integrated Information Theory and Isomorphic Feed-Forward Philosophical Zombies

Entropy ◽

10.3390/e21111073 ◽

2019 ◽

Vol 21 (11) ◽

pp. 1073 ◽

Cited By ~ 3

Author(s):

Jake R. Hanson ◽

Sara I. Walker

Keyword(s):

Information Theory ◽

Subjective Experience ◽

Original System ◽

Necessary Condition ◽

Mathematical Framework ◽

Hard Problem ◽

The Hard Problem ◽

Labeling Scheme ◽

Integrated Information Theory ◽

Integrated Information

Any theory amenable to scientific inquiry must have testable consequences. This minimal criterion is uniquely challenging for the study of consciousness, as we do not know if it is possible to confirm via observation from the outside whether or not a physical system knows what it feels like to have an inside—a challenge referred to as the “hard problem” of consciousness. To arrive at a theory of consciousness, the hard problem has motivated development of phenomenological approaches that adopt assumptions of what properties consciousness has based on first-hand experience and, from these, derive the physical processes that give rise to these properties. A leading theory adopting this approach is Integrated Information Theory (IIT), which assumes our subjective experience is a “unified whole”, subsequently yielding a requirement for physical feedback as a necessary condition for consciousness. Here, we develop a mathematical framework to assess the validity of this assumption by testing it in the context of isomorphic physical systems with and without feedback. The isomorphism allows us to isolate changes in Φ without affecting the size or functionality of the original system. Indeed, the only mathematical difference between a “conscious” system with Φ > 0 and an isomorphic “philosophical zombie” with Φ = 0 is a permutation of the binary labels used to internally represent functional states. This implies Φ is sensitive to functionally arbitrary aspects of a particular labeling scheme, with no clear justification in terms of phenomenological differences. In light of this, we argue any quantitative theory of consciousness, including IIT, should be invariant under isomorphisms if it is to avoid the existence of isomorphic philosophical zombies and the epistemological problems they pose.

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The Rubber Hand Illusion in Healthy Younger and Older Adults

Multisensory Research ◽

10.1163/22134808-00002614 ◽

2018 ◽

Vol 31 (6) ◽

pp. 537-555 ◽

Cited By ~ 3

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.

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

10.31234/osf.io/d8x9y ◽

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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World Modeling, Integrated Information, and the Physical Substrates of Consciousness; Hidden Sources of the Stream of Experience?

10.31234/osf.io/aud6e ◽

2021 ◽

Author(s):

Adam Safron

Keyword(s):

Information Theory ◽

Subjective Experience ◽

Hard Problem ◽

Synthetic Theory ◽

World Modeling ◽

Modeling Theory ◽

The Hard Problem ◽

Integrated Information Theory ◽

Integrated Information

In this brief commentary on The Hidden Spring: A Journey to the Source of Consciousness, I describe ways in which Mark Solms’ account of the origins of subjective experience relates to Integrated World Modeling Theory (IWMT). IWMT is a synthetic theory that brings together different perspectives, with the ultimate goal of solving the enduring problems of consciousness, including the Hard problem. I describe points of compatibility and incompatibility between Solms’ proposal and IWMT, with particular emphasis on how a Bayesian interpretation of Integrated Information Theory and Global (Neuronal) Workspace Theory may help identify the physical and computational substrates of consciousness.

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The Role of the Cerebellum in Dynamic Changes of the Sense of Body Ownership: A Study in Patients with Cerebellar Degeneration

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_00522 ◽

2014 ◽

Vol 26 (4) ◽

pp. 712-721 ◽

Cited By ~ 7

Author(s):

Mirta Fiorio ◽

Caterina Mariotti ◽

Marta Panzeri ◽

Emanuele Antonello ◽

Joseph Classen ◽

...

Keyword(s):

Cerebellar Ataxia ◽

Subjective Experience ◽

Premotor Cortex ◽

The Body ◽

Rubber Hand Illusion ◽

Subjective Feeling ◽

Body Ownership ◽

Rubber Hand ◽

Proprioceptive Drift

The sense of the body is deeply rooted in humans, and it can be experimentally manipulated by inducing illusions in at least two aspects: a subjective feeling of ownership and a proprioceptive sense of limb position. Previous studies mapped these different aspects onto anatomically distinct neuronal regions, with the ventral premotor cortex processing subjective experience of ownership and the inferior parietal lobule processing proprioceptive calibration. Lines of evidence suggest an involvement also of the cerebellum, but its precise role is not clear yet. To investigate the contribution of the cerebellum in the sense of body ownership, we applied the rubber-hand illusion paradigm in 28 patients affected by neurodegenerative cerebellar ataxia, selectively involving the cerebellum, and in 26 age-matched control participants. The rubber hand illusion is established by synchronous stroking of the participants' real unseen hand and a visible fake hand. Short asynchronous stroking does not bring about the illusion. We tested the subjective experience of the illusion, evaluated through a questionnaire and the proprioceptive drift of the real unseen hand toward the viewed rubber hand. In patients with cerebellar ataxia, we observed reduced sense of the subjective illusory experience specifically after synchronous stroking. In contrast, the proprioceptive drift was enhanced after synchronous and after asynchronous stimulation. These findings support the contention that the mechanisms underlying the presence of the illusion and the proprioceptive drift may be differently affected in different conditions. Impairment of the subjective sense of the illusion in cerebellar patients might hint at an involvement of cerebellar-premotor networks, whereas the proprioceptive drift typically associated with synchronous stroking appears to rely on other circuits, likely involving the cerebellum and the parietal regions.

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Psychometric properties of the embodiment scale for the rubber hand illusion and its relation with individual differences

Scientific Reports ◽

10.1038/s41598-021-84595-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Daniele Romano ◽

Angelo Maravita ◽

Marco Perugini

Keyword(s):

Individual Differences ◽

Personality Traits ◽

Subjective Experience ◽

Body Representation ◽

Self Esteem ◽

Healthy People ◽

Rubber Hand Illusion ◽

Body Ownership ◽

Rubber Hand ◽

The Individual

AbstractThe Rubber Hand Illusion (RHI) opened the investigation of the sense of body ownership in healthy people. By putting in slight contrast vision touch and proprioception, healthy people embody a fake hand in one's body representation. The easiness of the procedure, typically measured with a set of questions that capture the subjective experience, favoured its blooming. However, validation studies of embodiment questionnaires are lacking, and the individual differences that contribute to the embodiment received little attention. In our study, 298 participants underwent an RHI procedure following both synchronous and asynchronous (control) visuo-tactile stimulations. The study had multiple aims: (a) to explore the psychometric structure of a 27-items questionnaire largely used in the literature; (b) to build a psychometrically efficient scale to measure embodiment-related phenomena; (c) to explore whether and how individual differences (empathy, self-esteem and mindfulness) are associated with the experience of illusion. We found a relatively simple structure consisting of three components: embodiment of the rubber hand, disembodiment of the biological hand, physical sensations experienced during the procedure. The scales designed were psychometrically reliable and theoretically meaningful, encompassing 18 of the original items. Finally, by adopting a network analysis approach, we found that the embodiment is directly related to empathy and self-esteem, while disembodiment and physical sensation are unrelated to individual personality traits. The study provides substantial evidence to use the embodiment scale as a standard questionnaire for future RHI studies. Additionally, the correlations with personality traits suggest that the embodiment induced by the RHI deeply integrates with the complexity of the individuals and their differences.

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Awareness and integrated information theory identify plant meristems as sites of conscious activity

PROTOPLASMA ◽

10.1007/s00709-021-01633-1 ◽

2021 ◽

Author(s):

Anthony Trewavas

Keyword(s):

Information Theory ◽

Nervous System ◽

Complex Networks ◽

Environmental Changes ◽

Biological Function ◽

Human Consciousness ◽

Extrinsic Information ◽

Integrated Information Theory ◽

Conscious Activity ◽

Integrated Information

AbstractLacking an anatomical brain/nervous system, it is assumed plants are not conscious. The biological function of consciousness is an input to behaviour; it is adaptive (subject to selection) and based on information. Complex language makes human consciousness unique. Consciousness is equated to awareness. All organisms are aware of their surroundings, modifying their behaviour to improve survival. Awareness requires assessment too. The mechanisms of animal assessment are neural while molecular and electrical in plants. Awareness of plants being also consciousness may resolve controversy. The integrated information theory (IIT), a leading theory of consciousness, is also blind to brains, nerves and synapses. The integrated information theory indicates plant awareness involves information of two kinds: (1) communicative, extrinsic information as a result of the perception of environmental changes and (2) integrated intrinsic information located in the shoot and root meristems and possibly cambium. The combination of information constructs an information nexus in the meristems leading to assessment and behaviour. The interpretation of integrated information in meristems probably involves the complex networks built around [Ca2+]i that also enable plant learning, memory and intelligent activities. A mature plant contains a large number of conjoined, conscious or aware, meristems possibly unique in the living kingdom.

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