Synthetic stimuli attenuate the effect of attention on the dichotic right-ear advantage

This study assessed attentional effects on the right-ear advantage (REA) fo r a dichotic-listening task that used synthetic-speech syllables, Presentin g subjects with monaural tone cues at various intervals prior to dichotic p airs of natural-speech syllables, T. A. Mondor and M, P. Bryden 1991 (The i nfluence of attention on the dichotic REA. Neuropsychologia, 29, 1179-1190) found a reduced REA with longer intervals. This suggested that tone cues a t longer intervals helped overcome a right-ear attentional bias. Despite su fficient statistical power, in the present study no reduction in the REA wa s found with longer intervals between tones and synthetic-speech syllables. As synthetic-speech stimuli tend to fuse better into the percept of a sing le stimulus than do natural-speech stimuli, attentional effects on the REA may be reduced with dichotic stimuli that fuse. (C) 1999 Elsevier Science B .V. All rights reserved.