title: The effects of focal and global attentional systems on spatial biases.
abstract: The background page on which a stimulus is presented can influence the allocation of attention to that stimulus. The purpose of this study was to learn if there are hemispheric asymmetries in how background distraction affects attentional processing. Asymmetries were investigated by having right eye dominant subjects perform line bisections and manipulating the side of background distraction (right versus left), the eye of regard (right versus left), and the type of attention allocated (focal versus global). Overall subjects bisected lines to the left of center (pseudoneglect) and when viewing with the right eye (versus left) deviated more to the left. Subjects had more background distraction when viewing symbol than solid lines. Although overall, bias did not differ with the side of background distraction or the line being on one side or the other, when subjects viewed symbol, but not solid lines, this leftward bias was increased when the line was displaced to the right, thereby increasing the size of the left sided background. These findings suggest that when engaging the left hemisphere by using focused attention and placing the line on the right side, there is more distraction than when the right hemisphere is engaged.
authors.affiliation: Department of Neurology, University of Florida College of Medicine, USA.
authors.forename: Rachel M
authors.initials: RM
authors.lastname: Powers
authors.forename: Heidi L
authors.initials: HL
authors.lastname: Roth
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Heilman
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009048:Motor Skills / Q000502:physiology*; D010470:Perceptual Masking / Q000502:physiology; D012016:Reference Values; D013028:Space Perception / Q000502:physiology*; D013037:Spatial Behavior / Q000502:physiology*