Re-evaluating split-fovea processing in word recognition: effects of word length.
Several studies have claimed that, when fixating a word, letters to the left and right of fixation project to different hemispheres and are consequently subjected to different processes. In support of this claim, Lavidor M, et al. (2001; hereafter LES&B) report that lexical decisions were affected by increasing the number of letters to the left of fixation but not to the right, and that this indicates divided hemispheric access at the point of fixation to length-sensitive processes in the right hemisphere (RH). We re-evaluated these claims in Experiment 1 using Lavidor et al.'s original stimuli and procedure of merely instructing participants where to fixate. In contrast to the earlier study, increases in the number of letters to the left and right of the designated fixation location produced near-identical effects on reaction time, and increases to the left actually improved response accuracy and increases to the right impaired it. When larger stimuli were used to improve stimulus perceptibility and an eye-tracker monitored fixation accuracy (Experiment 2), left and right increases in the number of letters again produced near-identical effects on reaction time (and accuracy), but frequent and substantial fixation errors were revealed. When an eye-tracker ensured accurate fixations (Experiment 3), left and right increases in the number of letters again produced near-identical effects on reaction time and accuracy. Thus, the findings of all three experiments provide no support for the findings of LES&B (2001) and no evidence of split-fovea processing. The findings also indicate the dangers of assuming fixation of precisely-specified locations within words, both in experiments designed to reveal split-foveal processing and hemispheric asymmetry and in more normal circumstances of word perception.
Jordan
Timothy R
TR
School of Psychology, Faculty of Medicine and Biological Sciences, University of Leicester, Leicester, UK. prof.timjordan@le.ac.uk
Paterson
Kevin B
KB
Stachurski
Marcin
M
D000704:Analysis of Variance; D004192:Discrimination, Psychological / Q000502:physiology; D005133:Eye Movements / Q000502:physiology; D005403:Fixation, Ocular / Q000502:physiology*; D005584:Fovea Centralis / Q000502:physiology*; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D010364:Pattern Recognition, Visual / Q000502:physiology; D011932:Reading; D021641:Recognition, Psychology / Q000502:physiology*; D012016:Reference Values; D014705:Verbal Behavior / Q000502:physiology; D014785:Vision, Ocular / Q000502:physiology; D014794:Visual Fields / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology; D014825:Vocabulary