Foveational complexity in single word identification: contralateral visual pathways are advantaged over ipsilateral pathways.

Recognition of a single word is an elemental task in innumerable cognitive psychology experiments, but involves unexpected complexity. We test a controversial claim that the human fovea is vertically divided, with each half projecting to either the contralateral or ipsilateral hemisphere, thereby influencing foveal word recognition. We report a novel haploscope task: the two halves of a four-letter word were briefly presented to the two eyes in a Both condition (st|ep)(st|ep), a Contralateral condition (st|__)(__|ep), or an Ipsilateral condition (__|ep)(st|__), all yielding the same single word percept (step). The Both condition yielded superior perceptual recognition, followed by the contralateral projection, then the ipsilateral projection. These results demonstrate that the structure of the fovea influences even the recognition of short, foveally presented words. Projecting different parts of the same word to different hemispheres involves unforeseen complexities and opportunities for optimizing hemispheric coordination.