Dichotic listening: reversals in ear advantage

Synthetic CV syllables (stop+/a/) were presented dichotically to two listeners (mean REA = 11%). Although the main findings paralleled those of Studdert-Kennedy and Shankweiler [J. Acoust. Soc. Am. 48, 579–594 (1970)], the result of interest was for the 12 double-contrast pairs. The mean REA of 12% for these pairs obscured the fact that the ear advantage was REA = 62% with voiceless stops in the left ear (V − Left, V + Right), but LEA = 37% with voiceless stops in the right ear (V + Left, V − Right). The same reversal occurred for a third listener (LEA = 4%). This reversal was not obtained for voicing-contrasted, place-shared pairs for two of the three listeners, indicating that it does not reflect simply a V+ feature dominance. The reversal in ear advantage disappeared when the same listeners were tested with natural CVs, suggesting that (1) the synthetic CVs contain artifacts (although monotic scores were nearly 100%); (2) the reversal depends upon overall level of difficulty (scores were higher for natural CVs); or (3) that results with synthetic stimuli differ qualitatively from those with natural stimuli. [Supported by PHS Grant No. NS-12125.]