title: Voluntary self-touch increases body ownership.
abstract: Experimental manipulations of body ownership have indicated that multisensory integration is central to forming bodily self-representation. Voluntary self-touch is a unique multisensory situation involving corresponding motor, tactile and proprioceptive signals. Yet, even though self-touch is frequent in everyday life, its contribution to the formation of body ownership is not well understood. Here we investigated the role of voluntary self-touch in body ownership using a novel adaptation of the rubber hand illusion (RHI), in which a robotic system and virtual reality allowed participants self-touch of real and virtual hands. In the first experiment, active and passive self-touch were applied in the absence of visual feedback. In the second experiment, we tested the role of visual feedback in this bodily illusion. Finally, in the third experiment, we compared active and passive self-touch to the classical RHI in which the touch is administered by the experimenter. We hypothesized that active self-touch would increase ownership over the virtual hand through the addition of motor signals strengthening the bodily illusion. The results indicated that active self-touch elicited stronger illusory ownership compared to passive self-touch and sensory only stimulation, and show an important role for active self-touch in the formation of bodily self.
authors.affiliation: Graduate School of Science and Engineering, Saitama University Saitama, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Hara
authors.affiliation: Center for Neuroprosthetics, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland ; Neuroscience, Brain Mind Institute, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland.
authors.forename: Polona
authors.initials: P
authors.lastname: Pozeg
authors.affiliation: Center for Neuroprosthetics, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland ; Neuroscience, Brain Mind Institute, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland ; School of Engineering, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland.
authors.forename: Giulio
authors.initials: G
authors.lastname: Rognini
authors.affiliation: Department of Health Promotion Sciences, Tokyo Metropolitan University Tokyo, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Higuchi
authors.affiliation: Department of Health Promotion Sciences, Tokyo Metropolitan University Tokyo, Japan.
authors.forename: Kazunobu
authors.initials: K
authors.lastname: Fukuhara
authors.affiliation: Department of Precision Engineering, School of Engineering, The University of Tokyo Tokyo, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Yamamoto
authors.affiliation: Department of Precision Engineering, School of Engineering, The University of Tokyo Tokyo, Japan.
authors.forename: Toshiro
authors.initials: T
authors.lastname: Higuchi
authors.affiliation: Center for Neuroprosthetics, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland ; Neuroscience, Brain Mind Institute, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland ; Department of Neurology, University Hospital of Geneva Geneva, Switzerland.
authors.forename: Olaf
authors.initials: O
authors.lastname: Blanke
authors.affiliation: Center for Neuroprosthetics, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland ; Neuroscience, Brain Mind Institute, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland.
authors.forename: Roy
authors.initials: R
authors.lastname: Salomon
keywords: multisensory integration; robotics and haptic technology; rubber hand illusion; self-touch; sense of agency; sense of body ownership; volition