Re-evaluating split-fovea processing in word recognition: effects of retinal eccentricity on hemispheric dominance.
Several studies have claimed that hemispheric asymmetries affect word recognition right up to the point of fixation because each fovea is split precisely at its vertical midline and information presented either side of this midline projects unilaterally to different, contralateral hemispheres. To investigate this claim, four-letter words were presented to the left or right of fixation, either close to fixation entirely in foveal vision (0.15, 0.25, and 0.35 degrees from fixation) or further from fixation entirely in extrafoveal vision (2.00, 2.10, and 2.20 degrees from fixation). Fixation location and stimulus presentation were controlled using an eye-tracker linked to a fixation-contingent display and performance was assessed using a forced-choice task to suppress confounding effects of guesswork. A left hemisphere advantage was observed for words presented in extrafoveal locations but no hemisphere advantage (left or right) was observed for words presented in any foveal location. These findings support the well-established view that words encountered outside foveal vision project to different, contralateral hemispheres but indicate that this division for word recognition occurs only outside the fovea and provide no support for the claim that a functional split in hemispheric processing exists at the point of fixation.
Jordan
Timothy R
TR
School of Psychology, Faculty of Medicine and Biological Sciences, University of Leicester, Leicester, United Kingdom. Prof.TimJordan@leicester.ac.uk
Paterson
Kevin B
KB
Stachurski
Marcin
M
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D004215:Distance Perception / Q000502:physiology; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology; D005584:Fovea Centralis / Q000502:physiology*; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D021641:Recognition, Psychology / Q000502:physiology*; D014705:Verbal Behavior / Q000502:physiology; D014794:Visual Fields / Q000502:physiology; D014825:Vocabulary; D055815:Young Adult