Experience Of Illusion Research Articles

The rubber hand illusion questionnaire: An exploratory graph analysis of ownership, referral of touch, and control statements.

The rubber hand illusion is a well-known experiment that allows manipulation of one's own body experience. The original questionnaire gauges both the illusion experience and unforeseen experiences acting as control statements. In particular, two statements pertain to the referral of touch originating from the rubber hand (RoT), and one concerns the feeling of ownership of the rubber hand (SoO). Despite its prominence, the rubber hand illusion questionnaire has not undergone thorough examination of its psychometric properties. The literature reveals a tendency to use RoT and SoO statements interchangeably. In this study, we employed Exploratory Graph Analysis to explore the item structure and compared the correlation between SoO and RoT items in various conditions. While SoO and RoT are closely linked, our findings suggest potential separation. SoO and RoT statements consistently correlate, yet hints emerge that RoT might represent a distinct facet of the illusion. Correlations diminish beyond the perihand space, indicating a nuanced relationship. Additionally, moderate relationships between control statements and those measuring the illusion suggest that even control statements are modulated by the illusion experience. This study underscores the need for further exploration into the psychometric properties of body illusion questionnaires, prompting reflections on the interpretation in light of these results.

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

The 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.

Induced Illusory Body Ownership in Borderline Personality Disorder

Background: One aspect of selfhood that may have relevance for Borderline Personality Disorder (BPD) is variation in sense of body ownership. We employed the rubber hand illusion (RHI) to manipulate sense of body ownership in BPD. We extended previous research on illusory body ownership in BPD by testing: 1) two illusion conditions: asynchronous & synchronous stimulation, 2) relationship between Illusion experience and core BPD symptoms, and 3) relationship between illusion experience maladaptive personality traits. Methods: Participants (24 BPD, 21 control) underwent RHI procedures. We measured illusion strength (questionnaire responses), proprioceptive drift (perceived shift in physical hand position), BPD symptoms (DIB-R score), and maladaptive personality traits (PID-5). Results: For subjective illusion strength, we found a main effect of group (BPD > HC, F = 11.94 p = 0.001), and condition (synchronous > asynchronous, F(1,43) = 22.80, p < 0.001). There was a group x condition interaction for proprioceptive drift (F(1,43) = 6.48, p = 0.015) such that people with BPD maintained illusion susceptibility in the asynchronous condition. Borderline symptom severity correlated with illusion strength within the BPD group, and this effect was specific to affective symptoms (r = 0.481, p < 0.01). Across all participants, trait psychoticism correlated with illusion strength (r = 0.481, p <0.01). Conclusion: People with BPD are more susceptible to illusory body ownership than are healthy controls. This result is consistent with the robust clinical literature describing aberrant physical and emotional experience of self in BPD. A predictive coding interpretation of these results holds promise to develop testable mechanistic hypotheses for experiences of disrupted bodily self in BPD.

Modularist explanations of experience and other illusions.

Debates about modularity invariably involve a crucial premise about how visual illusions are experienced. This paper argues that these debates are wrongheaded, and that experience of illusions is orthogonal to the core issue of the modularity hypothesis: informational encapsulation.

Rubber hands in space: the role of distance and relative position in the rubber hand illusion

The rubber hand illusion (RHI) is a perceptual phenomenon in which participants experience ownership over a fake model hand through synchronous visuotactile stimulation. Several studies have shown that the illusion occurs only when both hands are in close proximity to each other. In the present study, we systematically examined the role of relative position (lateral, distal) and distance (13–75 cm) of the model hand (with respect to participants’ real hand) on illusion experience across both lateral and distal positions. Furthermore, we also compared different facets of the subjective illusion experience; the experience of the model hand being part of one’s body (i.e., ownership) and the perceptual fusion of vision and touch (i.e., referral of touch). In two experiments we observed indications for a stronger illusion experiences in distal compared to lateral positions of identical distances, indicating that the illusory effects may vary as a function of the relative position of the hand. Our results also showed that manipulations of distance differently modulated both facets of the illusion. While ownership was restricted to near distances, referral of touch sensations remained stable at farther distances. These results are interpreted in relation to variations in sensory weighting across different planes.

Induced illusory body ownership in borderline personality disorder.

One aspect of selfhood that may have relevance for borderline personality disorder (BPD) is variation in sense of body ownership. We employed the rubber hand illusion to manipulate sense of body ownership in BPD. We extended previous research on illusory body ownership in BPD by testing: (i) two illusion conditions: asynchronous and synchronous stimulation, (ii) relationship between illusion experience and BPD symptoms, and (iii) relationship between illusion experience and maladaptive personality traits. We measured illusion strength (questionnaire responses), proprioceptive drift (perceived shift in physical hand position), BPD symptoms (Revised Diagnostic Interview for Borderlines score), and maladaptive personality traits (Personality Inventory for DSM-5) in 24 BPD and 21 control participants. For subjective illusion strength, we found main effects of group (BPD > healthy control, F(1, 43) = 11.94, P = 0.001) and condition (synchronous > asynchronous, F(1, 43) = 22.80, P < 0.001). There was a group × condition interaction for proprioceptive drift (F(1, 43) = 6.48, P = 0.015) such that people with BPD maintained illusion susceptibility in the asynchronous condition. Borderline symptom severity correlated with illusion strength within the BPD group, and this effect was specific to affective (r = 0.45, P < 0.01) and cognitive symptoms (r = 0.46, P < 0.01). Across all participants, trait psychoticism correlated with illusion strength (r = 0.44, P < 0.01). People with BPD are more susceptible to illusory body ownership than controls. This is consistent with the clinical literature describing aberrant physical and emotional experiences of self in BPD. A predictive coding framework holds promise to develop testable mechanistic hypotheses for disrupted bodily self in BPD.

Age-related changes in the sense of body ownership: New insights from the rubber hand illusion.

How do age-related changes affect the sense of body ownership? This study tackles this issue by means of the rubber hand illusion (RHI), a widely used experimental tool for investigating the sense of body ownership. There is ample literature on the RHI in young populations, but research on age-related changes in the RHI is still scarce. Here we extend the use of the RHI to examine the changes in the sense of body ownership related to healthy aging. Subjective reports (i.e., questionnaire) and proprioceptive drift were compared among young (n = 22, age range 20–22 years), middle-aged (n = 22, age range 44–55 years), and older adults (n = 22, age range 60–72 years). A stronger subjective experience of illusion was observed in the young and older adults as compared to the middle-aged. No differences in proprioceptive drift were found between the three groups. These findings are discussed in relation to: 1) different stages of development of perceptual and cognitive components of the sense of body ownership, and 2) compensatory mechanisms.

Rubber Hand Illusion survives Ventral Premotor area inhibition: A rTMS study

The sense of body ownership is a fundamental feature that refers to the ability to recognize our body as our own, allowing us to interact properly with the outside world. Usually, it is explored by means of the Rubber Hand Illusion (RHI) during which a dummy hand is incorporated in the mental representation of one's own body throughout a multisensory (visuo-tactile) integration mechanism. Particular attention has been paid to the neurofunctional counterparts of this mechanism highlighting the pivotal role of an occipito-parieto-frontal network involving the Ventral Premotor area (PMv). To date, the specific role of the PMv in generating the sense of ownership is still unknown. In this study, we aimed at exploring the role of PMv in generating and experiencing the RHI. Off-line repetitive Transcranial Magnetic Stimulation (rTMS) was applied to a group of 24 healthy participants whilst changes in proprioceptive judgment and self-reported illusion sensations were collected and analysed separately. The PMv was not directly implicated in generating the sense of ownership. Indeed, its inhibition affected the explicit detection of the visuo-tactile congruence without interfering with the illusion experience itself. We hypothesized that the conscious visuo-tactile congruence detection may be independent from the conscious illusion experience. Also, our results support the view that the RHI grounds on a complex interaction between bottom-up and top-down processes, as the visuo-tactile integration per se may be not sufficient to trigger the subjective illusion.

The disappearing limb trick and the role of sensory suggestibility in illusion experience

Body ownership (the feeling that my body belongs to me) can be easily perturbed in healthy individuals by inducing bodily illusions. For example, dis-integrating vision, touch, and proprioception can produce the feeling that your limb is ‘lost’, such as in “the disappearing hand trick” (DHT). Following this illusion, participants report that the hand feels as though it is no longer part of the body, that it does not belong to them anymore, and that they do not know its location. However, it remains unknown whether this illusion can also be applied to the feet. Lower body ownership is disturbed in some populations, such as in Body Integrity Identity Disorder (BIID), where people have a longstanding desire to paralyze or amputate a (disowned) part of their body (i.e. usually the legs), thus exploring the efficacy and utility of lower body illusions might be useful for populations like such. In the current study, we induced the disappearing hand and foot trick in two groups of healthy adults. As the illusion crucially relies on illusory sensory feedback, we also explored if one's level of sensory suggestibility influenced the experience of the illusion. Questionnaire data showed that the DHT can be applied to the feet, as there was no difference in experience between those who experienced the illusion for the hands and those who experienced the illusion for the feet. Moreover, one's level of sensory suggestibility correlated positively with the experience of illusory sensations (like warmth, numbness, or the presence of an extra limb) following the illusion. We discuss the implications of bodily illusions in clinical populations and emphasize the critical role that sensory signals (even illusory) play in creating the bodily experience.

The Invisible Hand Illusion: Multisensory Integration Leads to the Embodiment of a Discrete Volume of Empty Space

The dynamic integration of signals from different sensory modalities plays a key role in bodily self-perception. When visual information is used in the multisensory process of localizing and identifying one's own limbs, the sight of a body part often plays a dominant role. For example, it has repeatedly been shown that a viewed object must resemble a humanoid body part to permit illusory self-attribution of that object. Here, we report a perceptual illusion that challenges these assumptions by demonstrating that healthy (nonamputated) individuals can refer somatic sensations to a discrete volume of empty space and experience having an invisible hand. In 10 behavioral and one fMRI experiment, we characterized the perceptual rules and multisensory brain mechanisms that produced this "invisible hand illusion." Our behavioral results showed that the illusion depends on visuotactile-proprioceptive integration that obeys key spatial and temporal multisensory rules confined to near-personal space. The fMRI results associate the illusion experience with increased activity in regions related to the integration of multisensory body-related signals, most notably the bilateral ventral premotor, intraparietal, and cerebellar cortices. We further showed that a stronger feeling of having an invisible hand is associated with a higher degree of effective connectivity between the intraparietal and ventral premotor cortices. These findings demonstrate that the integration of temporally and spatially congruent multisensory signals in a premotor-intraparietal circuit is sufficient to redefine the spatial boundaries of the bodily self, even when visual information directly contradicts the presence of a physical limb at the location of the perceived illusory hand.

Medically unexplained symptom reports are associated with a decreased response to the rubber hand illusion

Objective Medically unexplained symptoms (MUS) have been hypothesized to result from a distortion in perception, whereby top-down factors influence the process of body representation. Perceptual illusions provide a novel method of investigating this hypothesis. This study aimed to investigate whether self-reported unexplained symptoms are associated with altered experience of the rubber hand illusion (RHI). Methods A non-clinical MUS group with high scores on the Somatoform Dissociation Questionnaire (SDQ), and a control group with low scores on this scale, were exposed to the RHI. Illusion experience was measured by self-reports and by proprioceptive alteration. Results After controlling for somatosensory amplification and trait anxiety, the low-SDQ group responded significantly more strongly to the RHI on both questionnaire and proprioceptive measures of the illusion. In contrast, the high-SDQ group scored significantly higher on the Perceptual Aberrations Scale, a measure of bodily distortions in daily life. Conclusion These findings support the proposed link between MUS and disturbances in body representation, and suggest that a decreased reliance on current sensory inputs may contribute to symptom experience in susceptible individuals.

From Alienation to Hallucination: Peter Whitehead's &lt;i&gt;The Fall&lt;/i&gt; and the Politics of Perception in the 1960s

From Alienation to Hallucination:Peter Whitehead's The Fall and the Politics of Perception in the 1960s Tina Rivers (bio) Click for larger view View full resolution Figure 1. Peter Whitehead shooting The Fall, 1967-1968 Click for larger view View full resolution Figure 2. Peter Whitehead shooting The Fall, 1967-1968 [End Page 420] Click for larger view View full resolution Figure 3. Peter Whitehead shooting The Fall, 1967-1968 Click for larger view View full resolution Figure 4. Peter Whitehead shooting The Fall, 1967-1968 Click for larger view View full resolution Figure 5. Peter Whitehead shooting The Fall, 1967-1968 [End Page 421] Click for larger view View full resolution Figures 6-8. Peter Whitehead shooting The Fall, 1967-1968 [End Page 422] Click for larger view View full resolution Figure 9. Robert Kennedy in The Fall, 1969 Click for larger view View full resolution Figure 10. The Fall, 1969 [End Page 423] Click for larger view View full resolution Figure 11. The Fall, 1969 Click for larger view View full resolution Figure 12. The Fall, 1969 [End Page 424] Click for larger view View full resolution Figure 13. Title card for The Fall, 1969 [End Page 425] On September 26, 1967, the New York Film Festival screened the program "The London Scene," comprising two documentaries by thirty-year-old British filmmaker Peter Whitehead, who had flown to America for the occasion. Both the rollicking Tonite Let's All Make Love in London, now hailed as the quintessential portrait of Swinging London, and the sober Benefit of the Doubt, a critical examination of a theatrical production about Britain's role in the Vietnam War (both UK, 1967), played to a full house and were favorably reviewed. Somewhat cantankerously, Whitehead refused his accolades, complaining in his journal that the critic for the East Village Other (to name but one of his targets) was "fooled by the superficial obvious exterior commercial trappings of Tonite and the protest value of Benefit," vowing "next time—it must go much farther."1 After the screening, two young New Yorkers suggested to Whitehead that he make a film about their city; this inspired him to return in October with the intention of making a grave documentary about "where power lies at the moment," for which he planned to interview figures including presidential hopeful Robert F. Kennedy, New York mayor John Lindsay, and Black Panther Stokely Carmichael.2 But by the end of November, the project had permutated from an investigative report into an avant-garde feature film: in order to attempt a statement more substantive than that of his earlier work, he would integrate his documentary footage with a fictional story about a man "who decides to translate his despair and his will to protest into an act of premeditated murder" by assassinating a stranger at a rally.3 Returning again to New York in April 1968, Whitehead filmed happenings about town, interviews, and sequences of dialogue; he even joined the infamous student occupation at Columbia University, an event that radicalized his [End Page 426] politics (he subsequently declared himself "ready to take a gun and die," and actually bought one) and precipitated his return to En gland in June, under threat of surveillance and harassment by federal agents.4 In a remarkable coincidence of timing, Robert Kennedy was assassinated the day Whitehead left America, mirroring the assassination of Martin Luther King Jr. on the day of Whitehead's most recent arrival. Unable to "distinguish any more between what was real and what wasn't," Whitehead suffered a breakdown and spent "a harrowing three months" convalescing by editing his footage into The Fall.5 On one level, the resulting chef d'oeuvre is a tripartite allegory of the historical transition from nonviolent protest toward more radical forms of action in the late 1960s, made at a time when widespread social transformation seemed both possible and imminent. On another level, it is an experiment that attempts to "go much farther" than Whitehead's earlier documentaries by asking whether film—a medium that Whitehead described as ideologically compromised by its fundamental ties to the experience of illusion—can effect real change. In overlaying its examination...

Representation, Illusion, and the Cinema

Contemporary film theorists have tended to assume that the average film spectator is fundamentally deceived into believing what is seen is real. For example, in his influential essay, Ideological Effects of the Basic Cinematographic Apparatus, Jean-Louis Baudry argues that projection and narration in film work together to conceal from the spectator the technology and technique that underpin the production of the cinematic image, so that the film viewer believes she or he is in the presence of unmediated reality.' One task of the film theorist has been to expose the false nature of the beliefs about the image that the spectator is induced to hold by revealing the mechanisms of concealment and deception using Marxist-inspired and psychoanalytically informed semiotics. However, Noeil Carroll has argued recently, and in my view correctly, that what he terms the epistemically pernicious sense of implied by contemporary film theory's account of spectatorship, in which the spectator involuntarily takes the cinematic image to be real, does not reflect our experience of the cinema. The film spectator is not duped by the cinematic apparatus or forms of narration in the cinema; the spectator is fully aware that what is seen is only a film. However, the problem with Carroll's argument is that he not only rejects contemporary film theory's account of illusion, he rejects altogether the applicability of the concept of to the cinema on the basis that the cinematic image does not differ in any essential aspects from other forms of pictorial representation that do not involve illusion.2 In this essay I argue that the experience of illusion, suitably differentiated and correctly construed, is central to our experience of the cinema. My specific claims about the nature of in the cinema are deferred until the third and final sections of the essay. In the second section, I describe a form of the cinematic image shares with the photograph. It is derived from the photographic properties of the cinematic image. I call this kind of illusion because it trades upon the reproductive properties the cinematic image and the photograph share. In order to understand the significance of these reproductive properties for our experience of photography and film, I begin by contrasting how we perceive photographs and how we look at