title: The induced Roelofs effect: two visual systems or the shift of a single reference frame?
abstract: Cognitive judgments about an object's location are distorted by the presence of a large frame offset left or right of an observer's midline. Sensorimotor responses, however, seem immune to this induced Roelofs illusion, with observers able to accurately point to the target's location. These findings have traditionally been used as evidence for a dissociation of the visual processing required for cognitive judgments and sensorimotor responses. However, a recent alternative hypothesis suggests that the behavioral dissociation is expected if the visual system uses a single frame of reference whose origin (the apparent midline) is biased toward the offset frame. The two theories make qualitatively distinct predictions in a paradigm in which observers are asked to indicate the direction symmetrically opposite the target's position. The collaborative findings of two laboratories clearly support the biased-midline hypothesis.
authors.affiliation: Department of Psychology and Institute of Neuroscience, 1227 University of Oregon, Eugene, OR 97403-1227, USA. prd@darkwing.uoregon.edu
authors.forename: Paul
authors.initials: P
authors.lastname: Dassonville
authors.forename: Bruce
authors.initials: B
authors.lastname: Bridgeman
authors.forename: Jagdeep
authors.initials: J
authors.lastname: Kaur Bala
authors.forename: Paul
authors.initials: P
authors.lastname: Thiem
authors.forename: Anthony
authors.initials: A
authors.lastname: Sampanes
mesh_terms: D000328:Adult; D004215:Distance Perception / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009903:Optical Illusions; D011597:Psychomotor Performance / Q000502:physiology; D011601:Psychophysics