Cerebral hemispheric differences in visual perception of various types of verbal material.

Hemispheric differences in perception of various verbal material were sought in two groups of Ss: 10 normal adults (a control group) and 10 patients of the Neurosurgery Clinic with focal brain damage either to the left or right hemisphere. The stimuli were letters projected singly, in three-letter nonsense sequences or in three letter Polish words on a screen in the left or right visual half-field. The results obtained from the control groups indicate that the dominance of the left hemisphere is limited only to the meaningful verbal material. The results obtained from the patients support the first finding and show that this dominance can be cancelled by some left hemisphere damage without influence on the perception of meaningless material.