Attention to central and peripheral visual space in a movement detection task. III. Separate effects of auditory deprivation and acquisition of a visual language.

We employed event-related brain potentials (ERPs) and measures of signal detectability to compare attention to peripheral and central visual stimuli in normal hearing subjects who were born to deaf parents (HD Ss) and whose first language was American Sign Language (ASL). The results were compared with those obtained from normal hearing Ss and congenitally deaf Ss in the same paradigm. Task performance and ERPs during attention to the foveal region were similar in the 3 groups. In contrast, with attention to the peripheral stimuli the deaf Ss displayed attention effects over the occipital regions of both hemispheres that were several times larger than those in the hearing and the HD Ss. However, both HD and deaf Ss displayed lateral asymmetries in behavior and ERPs that were opposite in direction to those of the hearing Ss. Whereas hearing Ss detected the direction of target motion better when it occurred in the left visual field, deaf and HD Ss performed better for right visual field targets. Consistent with these results, the amplitude of the attention-related increases in the ERPs were larger from temporal and parietal regions of the right than the left hemisphere in hearing Ss, but were larger from the left than the right hemisphere in both the HD and the deaf Ss. These results suggest that auditory deprivation and the acquisition of a visual language have marked and different effects on the development of cortical specializations in humans.