Re-evaluating split-fovea processing in word recognition: effects of word length during monocular viewing

Several studies have claimed that, when fixating a word, a precise split in foveal processing causes all letters to the left and right of fixation to project to different, contralateral hemispheres (split-fovea theory--SFT). In support of this claim, Lavidor et al. (2001; hereafter LES&B) reported that lexical decisions were affected by the number of letters to the left of fixation but not the right, and that this indicates a functional division in hemispheric processing at the point of fixation. Jordan, Paterson, and Stachurski (Cortex, 2009; hereafter JP&S) re-evaluated these claims over 3 experiments using LES&B's original stimuli and procedures and found no support for the findings of LES&B. Following LES&B, JP&S presented stimuli binocularly (i.e., as in normal viewing). However, this procedure has its own complications for SFT (and for assessing the validity of the theory) because the two eyes often do not fixate the same location. Consequently, we report two further experiments which used an eye-tracker to ensure fixation accuracy and monocular viewing to eliminate influences of fixation disparity. Experiment 1 used the same-sized typeface as JP&S, and Experiment 2 used a larger typeface to approximate normal reading size. In line with the findings of JP&S, neither experiment could replicate the findings of LES&B and both experiments showed simply that word recognition was easier when fixations were made towards the beginning of words. Thus, after a total of 5 separate experiments, using binocular and monocular viewing conditions and stimuli presented in a range of sizes, none of these experiments has been able to replicate the findings of LES&B or provide any evidence for a functional division in hemispheric processing at the point of fixation.