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bioRxiv · 10.1101/2020.05.04.076497

The contribution of stimulating multiple body parts simultaneously to the illusion of owning an entire artificial body

Abstract

The full-body ownership illusion exploits multisensory perception to induce a feeling of ownership for an entire artificial body. Whilst previous research has shown that the synchronous visuotactile stimulation of a single body part is sufficient for illusory ownership over the whole body, the effect of combining multisensory stimulation across multiple body parts remains unknown. Therefore, 48 healthy adults participated in conditions of a full-body ownership illusion involving synchronous or asynchronous visuotactile stimulation to one, two or three body parts simultaneously (2 x 3 design). We developed a novel questionnaire to isolate the sense of ownership of five specific body parts (left leg, right leg, left arm, right arm, and trunk) from the full-body ownership experience and sought not only to test for greater (part and whole) body ownership in synchronous versus asynchronous stimulation, but also, potentially varying degrees of illusion intensity related to the number of body parts stimulated. As expected, illusory full-body ownership and all five body-part ownership ratings were significantly higher following synchronous stimulation (all p values [≤].01). Since non-stimulated body parts also received significantly higher ownership ratings following synchronous stimulation, the results are consistent with an illusion engaging the entire body. We further noted that ownership ratings for the right body parts (often stimulated) were significantly higher than ownership ratings for the left body parts (never stimulated). Regarding explicit feelings of full-body ownership, subjective ratings were not significantly enhanced by increasing the number of synchronously stimulated body parts (synchronicity x number stimulated interaction; p.099). Instead, median ratings indicated a moderate affirmation (+1) of full-body illusory sensation for all three synchronous conditions; a finding mirrored by full-body illusion onset time. The results support the notion that feelings of full-body ownership are mediated by a generalisation from stimulated part(s)-to-whole, supported by processes related to multisensory body perception.

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BibTeXRIS

O'Kane, S. H., Ehrsson, H. H.. 2020-05-04. The contribution of stimulating multiple body parts simultaneously to the illusion of owning an entire artificial body. https://doi.org/10.1101/2020.05.04.076497

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