Hemispheric differences in the effect of selective attention on the electrophysiological response to semantic processing

Two event-related potentials experiments examined the extent to which color-cued selective attention differentially modified semantic processing of single words in the cerebral hemispheres. Attentional status of the prime and target were manipulated within and between experiments. Lateralized presentation of associatively and categorically related words that shared common features (DOCTOR-NURSE) produced a significant N400 semantic priming effect in the left visual field/right hemisphere regardless of the attentional status of the prime or target. For the right visual field/left hemisphere, significant priming was produced in all conditions except when both the prime and target were ignored. In conjunction with ERP findings of effective early selection based on color, these results are interpreted as providing evidence for a view of attention as acting at multiple stages in the reading process, and against a simple sensory gain control interpretation of selective attention.