title: Minding gaps on the skin: Opposite bisection biases on forehead and back of one's head.
abstract: Humans perceive the world from an egocentric perspective, while being able to mentally take a third person's perspective. Graphesthesia tasks revealed that letters written on the back of one's own head are consistently perceived from an embodied perspective, while the perspective on one's front is less consistent and often disembodied. We developed a cutaneous gap bisection task as a more discrete measure of the perspective on the body. In analogy to a visual pseudoneglect, we expected bisections to deviate toward the left ear when perceived from an embodied perspective. While this hypothesis was confirmed for gap bisections on the back, the results on the front suggest overall a disembodied perspective. Contrary to our expectation, this pattern was not predicted by the spontaneous perspective participants took in a graphesthesia task, indicating different cognitive mechanisms. We discuss these findings in the frame of the current literature on spatial attention and perspective taking.
authors.affiliation: Neuropsychology Unit, Department of Neurology, University Hospital Zurich, Zurich, Switzerland; Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland. Electronic address: bigna.lenggenhager@gmail.com.
authors.forename: Bigna
authors.initials: B
authors.lastname: Lenggenhager
authors.affiliation: Neuropsychology Unit, Department of Neurology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Christine
authors.initials: C
authors.lastname: Busch
authors.affiliation: Neuropsychology Unit, Department of Neurology, University Hospital Zurich, Zurich, Switzerland; Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.
authors.forename: Peter
authors.initials: P
authors.lastname: Brugger
mesh_terms: D000328:Adult; D005260:Female; D005546:Forehead; D006257:Head; D006801:Humans; D008297:Male; D012867:Skin; D013028:Space Perception / Q000502:physiology*; D055698:Touch Perception / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*
keywords: Body space; Cutaneous perception; Embodiment; Line bisection; Perspective; Pseudoneglect; Visual–somatosensory interactions