Abstract
A distinctive dominance effect of the steady-state vowel /a/ sound in the non-verbal hemisphere in Western Ss was found by Tsunoda's tapping test. In contrast to these results, several studies carried out with Western Ss using Kimura's dichotic listening test did not show any distinctive tendency for the dominance effect of vowel sounds. In this experiment, the author intended to set up a tapping test analogous to the Kimura's test using syllables. Test subjects were 12 Westerners and 6 second-generation Japanese. The cerebral dominance of vowel /a/ without loading of /doop/ was non-dominant side, whereas in the loading condition, the original pattern disappered completely and a new pattern lateralized to the dominant hemisphere was observed. The grade of the dominancy shift of vowel sounds in the dichotic test mainly depends upon the experimental condition. If a technique free from the influence of the contralateral shift had been applied, more clear-cut results could have been obtained.
