Effect of acoustic variation in stimuli on response patterns in dichotic listening

Abstract

Two sets of tapes for dichotic listening were prepared from synthetic stop‐vowel stimuli which varied on a voice‐onset‐time (VOT) continuum. Each set contained the same three voiced syllables (ba, da, ga) in combination with one of two sets of voiceless stimuli which differed in VOT by 30 msec from Set I to Set II. The two sets of voiceless stimuli differed only in acoustic structure, not in the listeners' identification. Six stimulus‐onset asynchronies (SOA) were used for each of four listeners who demonstrated right‐ear advantages. Set I results differed from Set II results in the SOA at which the left‐ear score surpassed the right‐ear score when the left‐ear signal was lagged. Results are discussed with reference to a “phonetic processing” hypothesis [Berlin et al., J. Acoust. Soc. Am. 53, 699–709 (1973) and Studdert‐Kennedy et al., J. Acoust. Soc. Am. 48, 599–602 (1970)] and to an “acoustic interference” hypothesis [Speaks et al., J. Acoust. Soc. Am. 57, S52 (A) (1975)]. [Supported by USPHS Grant No. NS‐12125.]