Right hemisphere advantage in processing Cantonese level and contour tones: evidence from dichotic listening.

The brain lateralization pattern of Cantonese tonal processing was examined with the dichotic listening (DL) paradigm. Three factors were manipulated systematically in the study. First, the processing of level tones was compared with that of contour tones. Second, the influence of a linguistic context in tonal processing was studied by contrasting the patterns of brain lateralization for real syllables, pseudo-syllables, and hums. Finally, the discrimination and the identification tasks were used to test how processing depth might modulate the results obtained. A right hemisphere advantage (RHA) was obtained regardless of tone type, stimulus type, and task. In addition, the performance on level tones was in general better than that on contour tones. These findings suggest that Cantonese speakers are highly sensitive to the acoustic features of lexical tones, which supports the acoustic view about tonal processing.