Hemisphericity and top-down processing of language.

This study investigated the impact of contextual prompts (priming words and sentences) on the classical finding of superior performance with right visual field stimulation in a lexical decision task. Subjects were presented with prompts of varying lengths (one, three, or six words). The prompts were followed by a target stimulus (word/nonword) to the right or the left visual field. Subjects were required to respond whether the target was a word or a nonword. The major purpose of the study was to determine the extent of right visual field (RVF) superiority, reflecting left hemisphere superiority, in language processing when target stimuli are preceded by semantically meaningful prompts. The results showed that increasing the number of priming words congruent with the target (creating a meaningful context) increased the advantage of the RVF over the left visual field presentation in lexical decision. Thus, even with an available strategy provided by congruent priming stimuli, RVF superiority in lexical decision is retained and even increased.