Susceptibility to the rubber hand illusion does not tell the whole body-awareness story

Abstract

The rubber hand illusion (RHI) is an enigmatic illusion that creates a feeling of owning an artificial limb. Enthusiasts of this paradigm assert that it operationalizes bodily self-awareness, but there are reasons to doubt such a clear link. Because little is known about other functional contributions to the RHI, including effects of context-dependent visual processing and cognitive control or the ability to resolve intermodal conflict, we carried out two complementary experiments. In the first, we examined the relationships between the RHI and (1) body awareness, as assessed by the Body Perception Questionnaire (BPQ); (2) context-dependent visual processing, as assessed by the rod-and-frame test (RFT); and (3) conflict resolution, as assessed by the Stroop test. We found a significant positive correlation between the RHI-associated proprioceptive drift and context-dependent visual processing on the RFT, but not between the RHI and body awareness on the BPQ. In the second experiment, we examined the RHI in advanced yoga practitioners with an embodied lifestyle and a heightened sense of their own body in space. They succumbed to the illusion just as much as did yoga-naïve control participants, despite significantly greater body awareness on the BPQ. These findings suggest that susceptibility to the RHI and awareness of one's own body are at least partially independent processes.

Alexithymia modulates the experience of the rubber hand illusion

“…However, other studies also failed to replicate this effect (i.e., David et al, 2014) and, more importantly, the relevance of this measure as a correlate of subjective experience of the illusion has been questioned (e.g., Rohde et al, 2013). …”

Rubber hand illusion induced by touching the face ipsilaterally to a deprived hand: evidence for plastic “somatotopic” remapping in tetraplegics

“…Although the RHI is largely used as a direct index of body-ownership, studies demonstrate an elevated inter-individual variability in the effect (Haans et al, 2012) as well as a partial independency from bodily awareness (David et al, 2013). Moreover, the fact that the mere sight of the rubber hand triggers the RHI more than the tactile sensation does (Pavani et al, 2000; Aimola Davies et al, 2010) might suggest that personal variables, such as suggestibility, play a role in the phenomenon beyond neuroplasticity.…”

Achronopresence: how temporal visuotactile and visuomotor mismatches modulate embodiment

“…This could suggest that the effect might be mediated by stronger visual dependence: participants with stronger visual dependence would not be so sensitive to incongruencies to other senses since they rely stronger on vision as compared to other senses (Witkin & Asch, 1948). Indeed visual dependence has shown to be correlated with susceptibility to various multisensory illusions (David, Fiori, & Aglioti, 2014;Rothacher, Nguyen, Lenggenhager, Kunz, & Brugger, 2018). A stronger dependence on visual signals could thus explain why there was no difference in the decay of ownership for visuomotor and visuotactile tasks for participants with low delay sensitivity, however we did not objectively assess such dependence.…”