title: Visual information and rubber hand embodiment differentially affect reach-to-grasp actions.
abstract: During the "rubber hand illusion" (RHI) participants feel touch originating from an artificial hand, which is felt to belong to the own body. The perceived location of the real hand is shifted towards the location of the artificial hand. However, evidence as to whether the RHI is accompanied by alterations of hand action is mixed. We found that the perceived size of one's own hand was affected by the size of the artificial hand that was used to elicit the illusion. Moreover, we tested a possible transfer of the RHI to a reach-to-grasp action. We observed that hand transport (i.e., reach) errors after RHI induction were independent of artificial hand size, showing that the parameter which is important for these reaching errors is the hand's perceived location. Results thus show that the RHI affects not only perceptual, but also action processing. In contrast, grip aperture was affected by artificial hand size independent of the RHI, suggesting that visual information about hand size affects grasping independent of embodiment of the artificial hand. Grip size increased with artificial hand size; this effect is explained by a higher reliance on proprioceptive information during blind reaching after receiving distorted visual information.
authors.affiliation: Biological Psychology and Neuropsychology, University of Hamburg, von-Melle-Park 11, 20146 Hamburg, Germany. tobias.heed@uni-hamburg.de
authors.forename: Tobias
authors.initials: T
authors.lastname: Heed
authors.forename: Michael
authors.initials: M
authors.lastname: Gründler
authors.forename: Jennifer
authors.initials: J
authors.lastname: Rinkleib
authors.forename: Franziska H
authors.initials: FH
authors.lastname: Rudzik
authors.forename: Thérèse
authors.initials: T
authors.lastname: Collins
authors.forename: Edward
authors.initials: E
authors.lastname: Cooke
authors.forename: J Kevin
authors.initials: JK
authors.lastname: O'Regan
mesh_terms: D000328:Adult; D005260:Female; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D007088:Illusions / Q000502:physiology*; D008297:Male; D009068:Movement / Q000502:physiology*; D011434:Proprioception / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology*; D014163:Transfer, Psychology / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*