scholarly journals Serious problems with interpreting rubber hand illusion experiments

2020 ◽  
Author(s):  
Warrick Roseboom ◽  
Peter Lush

The rubber hand illusion (RHI), in which participants report experiences of ownership over a fake hand, appears to demonstrate that subjective ownership over one’s body can be easily disrupted. In RHI, ownership is typically quantified through ratings of agreement with statements putatively about body ownership. It was recently shown that propensity to agree with these statements is correlated with trait phenomenological control (the ability to generate experience to meet expectancies arising from direct or indirect suggestion) and that existing methods of controlling for suggestion effects in RHI are invalid. Here, we present the results of simulated experiments that mimic standard practice in RHI studies, using real participant data. In each experiment the sample was biased in selection for trait phenomenological control. Using samples comprised of participants higher in trait phenomenological control almost guarantees that an experiment provides evidence for RHI. By contrast, samples comprised of only participants lower in trait phenomenological control find evidence for RHI only around half the time (and “ownership” experience just 4% of the time). It is therefore likely that existing RHI experiments have studied phenomenological control by proxy. Previous RHI studies cannot be used to make inferences about the sense of ownership in humans generally.

2020 ◽  
Author(s):  
Arran T Reader ◽  
Victoria S Trifonova ◽  
H. Henrik Ehrsson

Body ownership refers to the distinct sensation that our observed body belongs to us, which is believed to stem from multisensory integration. The rubber hand illusion (RHI) provides the most well-known evidence for this proposal: synchronous (but not asynchronous) stroking of a fake hand and a participant’s real hidden hand can induce a sense of ownership over the false limb. Whilst the RHI may interfere with object-directed action and alter motor cortical activity, it is not yet clear whether a sense of ownership over an artificial hand has functional consequences for movement production per se. As such, we performed two motion-tracking experiments (n=117) to examine the effects of the RHI on the reaction time, acceleration, and velocity of rapid index finger abduction. We also examined whether subjective components of the illusion and the associated changes in hand position sense (proprioceptive drift) were correlated with changes in the kinematic variables. We observed convincing evidence that the induction of the RHI did not alter any kinematic variables. Moreover, the subjective sensations of rubber hand ownership, referral of touch, and agency did not convincingly correlate with kinematic variables, and nor did proprioceptive drift, suggesting that changes in body representation elicited by the RHI may not influence basic movement. Whilst experiment 1 suggested that individuals reporting a greater sensation of the real hand disappearing performed movements with smaller acceleration and velocity following illusion induction, we did not replicate this effect in a second experiment, suggesting that these effects may be small or not particularly robust.


PLoS ONE ◽  
2018 ◽  
Vol 13 (11) ◽  
pp. e0207528 ◽  
Author(s):  
Angela Marotta ◽  
Massimiliano Zampini ◽  
Michele Tinazzi ◽  
Mirta Fiorio

2019 ◽  
Vol 44 (3) ◽  
pp. 177-184 ◽  
Author(s):  
Merel Prikken ◽  
Anouk van der Weiden ◽  
Heleen Baalbergen ◽  
Manon H.J. Hillegers ◽  
René S. Kahn ◽  
...  

Cortex ◽  
2018 ◽  
Vol 104 ◽  
pp. 180-192 ◽  
Author(s):  
Laura Crucianelli ◽  
Charlotte Krahé ◽  
Paul M. Jenkinson ◽  
Aikaterini (Katerina) Fotopoulou

2012 ◽  
Vol 25 (0) ◽  
pp. 52 ◽  
Author(s):  
Nicholas P. Holmes ◽  
Tamar R. Makin ◽  
Michelle Cadieux ◽  
Claire Williams ◽  
Katherine R. Naish ◽  
...  

The rubber hand illusion (RHI) is a multisensory (visual, tactile, proprioceptive) illusion in which participants report body ownership over, mislocalize actual hand position to, and feel touches applied to, the rubber hand. For many years, researchers have used changes in perceived hand position, measured by inter-manual pointing, as a more objective measure of the illusion than verbal reports alone. Despite this reliance, there is little evidence to show that the illusion of hand ownership is directly related to perceived hand position. We developed an adaptive staircase procedure to measure perceived hand position, and tested whether the RHI affected perceived hand position. In two experiments we found a significant illusion of ownership, as well as significant changes in perceived hand position, but these two measures were uncorrelated. In a third experiment using more typical RHI procedures, we again replicated significant illusions of ownership and changes in hand position, but again the measures were uncorrelated. We conclude that viewing and feeling touches applied to a dummy hand results in clear illusions of ownership and changes in hand position, but via independent mechanisms.


2018 ◽  
Vol 5 (5) ◽  
pp. 172170 ◽  
Author(s):  
Yuki Sato ◽  
Toshihiro Kawase ◽  
Kouji Takano ◽  
Charles Spence ◽  
Kenji Kansaku

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.


2018 ◽  
Vol 31 (6) ◽  
pp. 537-555 ◽  
Author(s):  
Jennifer L. Campos ◽  
Graziella El-Khechen Richandi ◽  
Babak Taati ◽  
Behrang Keshavarz

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.


2017 ◽  
Vol 28 (3) ◽  
pp. 330-337 ◽  
Author(s):  
Elena Nava ◽  
Nadia Bolognini ◽  
Chiara Turati

In this study, we investigated the contribution of tactile and proprioceptive cues to the development of the sense of body ownership by testing the susceptibility of 4- to 5-year-old children, 8- to 9-year-old children, and adults to the somatic rubber-hand illusion (SRHI). We found that feelings of owning a rubber hand in the SHRI paradigm, as assessed by explicit reports (i.e., questionnaire), are already present by age 4 and do not change throughout development. In contrast, the effect of the illusion on the sense of hand position, as assessed by a pointing task, was present only in 8- to 9-year-old children and adults; the magnitude of such capture increased with age. Our findings reveal that tactile-proprioceptive interactions contributed differently to the two aspects characterizing the SRHI: Although the contribution of such interactions to an explicit sense of self was similar across age groups, their contribution to the more implicit recalibration of hand position is still developing by age 9.


2018 ◽  
Author(s):  
Maria Laura Filippetti ◽  
Louise P. Kirsch ◽  
Laura Crucianelli ◽  
Aikaterini Fotopoulou

AbstractOur sense of body ownership relies on integrating different sensations according to their temporal and spatial congruency. Nevertheless, there is ongoing controversy about the role of affective congruency during multisensory integration, i.e. whether the stimuli to be perceived by the different sensory channels are congruent or incongruent in terms of their affective quality. In the present study, we applied a widely used multisensory integration paradigm, the Rubber Hand Illusion, to investigate the role of affective, top-down aspects of sensory congruency between visual and tactile modalities in the sense of body ownership. In Experiment 1 (N = 36), we touched participants with either soft or rough fabrics in their unseen hand, while they watched a rubber hand been touched synchronously with the same fabric or with a ‘hidden’ fabric of ‘uncertain roughness’. In Experiment 2 (N = 50), we used the same paradigm as in Experiment 1, but replaced the ‘uncertainty’ condition with an ‘incongruent’ one, in which participants saw the rubber hand being touched with a fabric of incongruent roughness and hence opposite valence. We found that certainty (Experiment 1) and congruency (Experiment 2) between the felt and vicariously perceived tactile affectivity led to higher subjective embodiment compared to uncertainty and incongruency, respectively, irrespective of any valence effect. Our results suggest that congruency in the affective top-down aspects of sensory stimulation is important to the multisensory integration process leading to embodiment, over and above temporal and spatial properties.


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