Stimulus dominance in dichotic listening

Twenty-four listeners received 20 dichotic-listening runs of natural stop-vowel syllables. Listeners marked 2 responses for each of 30 pairs of syllables per run, which yielded 480 pairs of responses for each of the 30 pairs of syllables. The principal analysis focused on 'stimulus dominance' wherein a significantly higher score occurs for one of the competing syllables in a pair regardless of the ear to which that syllable is presented. With 30 pairs of syllables, there were 15 possible instances of stimulus dominance; 11 were observed. The voicing feature was contrasted for 9 of the 15 pairs. Seven of those pairs resulted in significantly higher scores (dominance) for the voiceless stop than for the voiced, one resulted in a higher score for the voiced member of the pair, and for one pair the scores for the 2 members were essentially the same. Stimulus dominance cannot, however, be characterized sufficiently as a dominance of voiceless over voiced stops; 3 of the 6 pairs in which voicing was shared also produced significant stimulus dominance. Stimulus dominance for a given pair of syllables may interact with, and in some cases override, the ear advantage. Of the 30 pairs of syllables, 11 produced a significant right ear advantage (REA), 9 produced a significant left ear advantage (LEA), and for 10 pairs the ear advantage was not significantly different from zero. For a specific pair of syllables, the direction of ear advantage usually corresponded to the ear that received the dominant syllable.