| |
Abstract:
This study focuses on lateral asymmetries in auditory
processing under dichotic-listening conditions using evoked
potentials (EP's). This procedure involves the presentation of
stimuli to both ears simultaneously and is commonly used to study
hemispheric differences in processing auditory input. Previous
research on dichotic-listening has shown a right-ear advantage for
speech sounds. This finding is typically associated with the left
hemisphere's dominance in language processing. In a previous study,
we demonstrated a right-ear advantage for short- duration tones in
a dichotic-listening paradigm (using a white noise mask as a
competing stimulus). This suggests that certain stimulus features,
rather than speech per se, may account for the left-hemispheric
advantage. The current study further investigated the role of
stimulus features by comparing laterality effects of speech sounds
and short-duration tones. In a counterbalanced order, speech sounds
(e.g. "ba" and "ta") or tones were presented to one ear, while a
mask or no mask was simultaneously presented to the other ear. The
participant listened passively to 8 blocks of 200 trials.
Hemispheric differences in the N1 component of the evoked potential
were then compared across stimulus conditions. The results indicate
that short-duration tones mimic the degree to which speech sounds
exhibit a right-ear advantage. This is consonant with the notion
that basic stimulus features contribute to laterality effects in
the auditory system.
|
