Differential hemispheric processing in the recognition of Chinese characters with different structures in foveal and parafoveal vision

Abstract

Whether foveal representation in reading is initially split and contralaterally projected to different hemispheres or bilaterally projected remains a controversial issue. Here we examine visual field asymmetry effects in naming Chinese characters with different structures, with characters presented either to the left visual field or the right visual field (RVF), and either within or outside foveal vision (eccentricity). We show that overall the RVF advantage in naming characters was significant in both eccentricity conditions (fovea vs. parafovea), with a stronger effect in parafoveal vision. This suggests that foveal splitting may not be an all-or-none phenomenon but has a graded effect. When examining characters with different structures separately, this interaction between visual field and eccentricity was significant only in the dominant, right-heavy character structure type, but not in the minority left-heavy or symmetric structure types, suggesting a modulation of character structure or type frequency on the eccentricity effect. In addition, existence of a phonetic radical modulated the visual field asymmetry effect differentially in different character structure types; however this effect did not interact with eccentricity. This result thus suggests that character structure and existence of a phonetic radical have differential modulation on character processing in the foveal and parafoveal vision.