Rubber hands do not cross the midline

doi:10.1016/j.neulet.2011.09.010

Neuroscience Letters

Volume 504, Issue 3, 31 October 2011, Pages 191-194

https://doi.org/10.1016/j.neulet.2011.09.010 Get rights and content

Abstract

The rubber hand illusion (RHI) occurs when a person misattributes a fake hand as his or her own hand. Previously, the RHI has been examined with both the rubber hand and the participant‘s real hand uncrossed with regards to the participant‘s midline. The present study examined the strength of the illusion when the real hand, the fake hand or both hands are placed across the body midline. The illusion was induced by stroking the rubber hand and the real hand simultaneously. Asynchronous brushing served as a comparable condition since the RHI is not seen under these circumstances. Participants indicated where they felt their real hand was located by marking a sheet of paper under the table on which their unseen hand was placed. A significant RHI was observed with both the hands uncrossed. In contrast, no RHI was present when either hand was crossed over the midline. Additionally, a shift in hand judgment towards the midline was observed when participants crossed their real hand. These results indicate the importance of the midline in understanding representations of the body.

Highlights

► We examine how the rubber hand illusion (RHI) interacts with the body midline. ► Crossing either the rubber or the real hand eliminates the illusion. ► The RHI depends on integration of visual and proprioceptive signals. ► Multisensory integration appears disrupted when the hand crosses the midline.

Section snippets

Acknowledgments

This work was supported by a Natural Science and Engineering Council (NSERC) of Canada Discovery Grant to DIS. MLC was supported by a McMaster Graduate Student Scholarship. KW completed this work in partial fulfillment of the requirements for her undergraduate thesis. These results were presented at the International Multisensory Research Forum (IMRF) 2010 in Liverpool, UK (www.imrf.info/2010/203). Thank you to Greg Atkinson for photography.

References (20)

M. Costantini et al.
The rubber hand illusion: sensitivity and reference frame for body ownership
Conscious. Cogn.
(2007)
N.P. Holmes et al.
Muiltisensory interactions follow the hands across the midline: evidence from a non-spatial visual-tactile congruency task
Brain Res.
(2006)
D.M. Lloyd
Spatial limits on referred touch to an alien limb may reflect boundaries of visuo-tactile peripersonal space surrounding the hand
Brain Cogn.
(2007)
T.R. Makin et al.
On the other hand: dummy hands and peripersonal space
Behav. Brain Res.
(2008)
B. Roder et al.
Early vision impairs tactile perception in the blind
Curr. Biol.
(2004)
D.I. Shore et al.
Confusing the mind by crossing the hands
Cogn. Brain Res.
(2002)
M. Wada et al.
Effects of handedness on tactile temporal order judgment
Neuropsychologia
(2004)
K.C. Armel et al.
Projecting sensations to external objects: evidence from skin conductance response
Proc. R. Soc Lond. B: Biol. Sci.
(2003)
E. Azanon et al.
Alleviating the ‘crossed-hands’ deficit by seeing uncrossed rubber hands
Exp. Brain Res.
(2007)
M. Botvinick et al.
Rubber hands ‘feel’ touch that eyes see
Nature
(1998)

There are more references available in the full text version of this article.

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Contextual effects are also found in the illusions outlined in the previous section. In the rubber hand illusion, if the object placed in front of the participant is non-corporeal (Tsakiris et al., 2010a), is a rubber hand of a different skin tone (Farmer et al., 2012) or is placed in a spatially incongruent location (Bekrater-Bodmann et al., 2012; Cadieux et al., 2011; Costantini and Haggard, 2007; Folegatti et al., 2012; Hohwy and Paton, 2010; Holle et al., 2011; Makin et al., 2008), the sense of ownership over the object is modulated or not present at all. So it is clear that the context within which stimuli are perceived modulates multisensory expectations about stimuli, leading to variability in the likelihood that another body will be processed as “me”.
Recognising and representing one's self as distinct from others is a fundamental component of self-awareness. However, current theories of self-recognition are not embedded within global theories of cortical function and therefore fail to provide a compelling explanation of how the self is processed. We present a theoretical account of the neural and computational basis of self-recognition that is embedded within the free-energy account of cortical function. In this account one's body is processed in a Bayesian manner as the most likely to be “me”. Such probabilistic representation arises through the integration of information from hierarchically organised unimodal systems in higher-level multimodal areas. This information takes the form of bottom-up “surprise” signals from unimodal sensory systems that are explained away by top-down processes that minimise the level of surprise across the brain. We present evidence that this theoretical perspective may account for the findings of psychological and neuroimaging investigations into self-recognition and particularly evidence that representations of the self are malleable, rather than fixed as previous accounts of self-recognition might suggest.
The role of distance from the body and distance from the real hand in ownership and disownership during the rubber hand illusion
2013, Acta Psychologica
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Therefore, the current results suggest that, rather than needing to be near the real hand, the fake hand just needs to be near to a part of the body, such that it is peripersonal space, as opposed to perihand space per-se, that is key for subjective reports of the RHI. Previously, observations of increased distance between the real and fake hands reducing the RHI despite the close proximity of the fake hand and trunk (Lloyd, 2007), also modulated fake hand position in terms of orientation and by crossing body midline, which have been found to inhibit the RHI (orientation Pavani, Spence, & Driver, 2000; crossing body midline e.g. Cadieux et al., 2011). Both of these factors were controlled in the current study, with only distance between the real and fake hands and relative distance from body midline being modified.
A key tool for investigating body ownership is the rubber hand illusion, in which synchronous multisensory feedback can induce feelings of ownership over a fake hand. Much research in the field aims to tease apart the mechanisms that underlie this phenomenon. Currently there is conflicting evidence as to whether increasing the distance between the real and fake hands (within reaching space) can reduce the illusion. The current study examines this further by modulating, not only the absolute distance between the real and fake hands but also their relative distance from body midline. It is found that the strength of the illusion is reduced only when the fake hand is both far from the real hand and far from the trunk; illusion scores over a fake hand in the same position can then be increased by moving the real hand nearer. This is related to peripersonal space surrounding the trunk and the hand. Subjective disownership of the real hand, and proprioceptive drift measures were also taken and may be driven by different mechanisms.
The rubber hand illusion modulates pseudoneglect
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After several minutes of synchronous stroking, the participant may report the perceived touch on the real hand as being produced by the visible stimulation of the rubber hand. Previous studies have applied the RHI to systematically investigate and manipulate the experience of embodiment, i.e. the subjective integration of an external object into one's body image [e.g. 14,4,15]. For instance, the RHI is perceived as stronger when elicited on the left compared to the right hand, suggesting right-hemispheric dominance for body ownership [17].
The rubber hand illusion (RHI) refers to the illusory perception of ownership of a rubber hand that may occur when covert tactile stimulation of a participant's hand co-occurs with overt corresponding stimulation of a rubber hand. It is proposed that integrating the rubber hand into one's body image may shift the subjective body midline away from the rubber hand. The present study investigated the influence of the RHI on pseudoneglect on the line bisection task, i.e. the leftward bias when marking the centre of horizontal lines, in 79 neurologically healthy adults. Overall, pseudoneglect was reduced after RHI application. Importantly, this effect was specific for individuals who reported having vividly experienced the illusion (high responders) as opposed to individuals who did not (low responders). Moreover, pseudoneglect was eliminated only after RHI application to the left hand. This pattern of results is consistent with functional hemispheric asymmetry for spatial processing and suggests that integrating the left sided rubber hand into one's body image shifts the subjective body midline to the right, thus counteracting pseudoneglect.
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View full text

Rubber hands do not cross the midline

Abstract

Highlights

Section snippets

Acknowledgments

Conscious. Cogn.

Brain Res.

Brain Cogn.

Behav. Brain Res.

Curr. Biol.

Cogn. Brain Res.

Neuropsychologia

Projecting sensations to external objects: evidence from skin conductance response

Proc. R. Soc Lond. B: Biol. Sci.

Alleviating the ‘crossed-hands’ deficit by seeing uncrossed rubber hands

Exp. Brain Res.

Rubber hands ‘feel’ touch that eyes see

Nature