[A new test for hemisphericity: the examination of its validity and reliability]

A new cognitive test for hemispherecity, based on the knowledge of hemispheric functional differences, was developed. In the first experiment, fifty subjects were examined their preferences for either visual-spatial or visual-verbal processing to the stimuli to which both types of processing were available. In the second experiment, ERP (Event Related Potentials) were measured in the two conditions: One, subjects processed the stimuli used in the first experiment as the visual-nonverbal stimuli, the other, subject processed the same stimuli as the visual-verbal stimuli. ERP from the left and the right hemispheres differed between both conditions in the later components. In the third experiment, both groups of subjects who preferred visual-verbal processing and visual-nonverbal processing were asked to report the Hiragana words presented tachistoscopically to the left or the right visual field. The former group of subjects showed a significant right visual field advantage while the latter group of subjects showed no visual field difference. These results confirm that the newly developed test for hemispherecity has appropriate validity and reliability.