Reevaluating split-fovea processing in word recognition: hemispheric dominance, retinal location, and the word-nonword effect.
Many studies have claimed that hemispheric projections are split precisely at the foveal midline and so hemispheric asymmetry affects word recognition right up to the point of fixation. To investigate this claim, four-letter words and nonwords were presented to the left or right of fixation, either close to fixation in foveal vision or farther from fixation in extrafoveal vision. Presentation accuracy was controlled using an eyetracker linked to a fixation-contingent display. Words presented foveally produced identical performance on each side of fixation, but words presented extrafoveally showed a clear left-hemisphere (LH) advantage. Nonwords produced no evidence of hemispheric asymmetry in any location. Foveal stimuli also produced an identical word-nonword effect on each side of fixation, whereas extrafoveal stimuli produced a word-nonword effect only for LH (not right-hemisphere) displays. These findings indicate that functional unilateral projections to contralateral hemispheres exist in extrafoveal locations but provide no evidence of a functional division in hemispheric processing at fixation.
Jordan
Timothy R
TR
University of Leicester, Leicester, England. prof.timjordan@leicester.ac.uk
Paterson
Kevin B
KB
Kurtev
Stoyan
S
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D005403:Fixation, Ocular / Q000502:physiology; D005584:Fovea Centralis / Q000502:physiology*; D007839:Functional Laterality; D006801:Humans; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D021641:Recognition, Psychology / Q000502:physiology*; D012160:Retina / Q000502:physiology*; D014794:Visual Fields / Q000502:physiology*; D014825:Vocabulary; D055815:Young Adult