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Interaural time just-noticeable-difference (jnd) of a narrow-band noise masked by a wideband noise was measured for nine different interaural configurations of the masking noise at a fixed signal-to-noise ratio. The narrow-band noise was 1/3 octave wide centered about 500 Hz, and the wideband masker was bandpass filtered between 250 and 1500 Hz. Our results are in agreement with earlier results with tones [M. F. Cohen, J. Acoust. Soc. Am. Suppl. 1 64, S35 (1978); J. Acoust. Soc. Am. 70, 1289-1293 (1981); J. E. Slocum and R. M. Stern, J. Acoust. Soc. Am. Suppl. 1 68, S60 (1980)] and are the opposite of what may be expected from the results of binaural detection experiments: the jnd is largest for the interaurally phase reversed masker and smallest for the diotic masker. In addition, no consistent relation was observed between the size of the jnd and the perceptual location of the masker. Predicted jnds were calculated from a model based on the interaural phase difference of the stimuli in the two ears and were in rough agreement with the experimental results. [ABSTRACT FROM AUTHOR]

Determines the impact of the characteristics of an immediately preceding vowel with the identification of vowel quality in selected vowel-like sounds. Generation of affected vowels; Presentation of pairs of vowels to listeners; Indications for ambiguous auditory characteristics.

In two experiments on normals we presented CV nonsense syllables both dichotically and monotically, with onsets of the syllables separated by 0, 15, 30, 60, and 90 msec (first experiment) and 0, 90, 180, 250, and 500 msec (second experiment). We found that when one of the CV's trailed the other by 30-60 msec, the trailing CV became more intelligible than when it was given simultaneously; the leading syllable's intelligibility dropped from its 'simultaneous' level when leading by 15 and 30 msec. The leading message was more intelligible between 15 and 250 msec when the two channels were mixed monotically. In the dichotic simultaneous conditon, voiceless consonants were more intelligible than voiced, especially in voiced-voiceless pairs. When the voiced CV trailed the voiceless CV, the former became almost as intelligible as its voiceless counterpart. A left hemisphere 'speech processor' was postulated, with suppression of information from ipsilateral sources during contralateral stimulation. The postulated 'speech processor' may be involved in acoustic-signal-vocal-tract control functions. [ABSTRACT FROM AUTHOR]

When dichotic nonsense syllables are presented to temporal lobectomy patients at equal intensities, the ear contralateral to the site of the lesion performs more poorly than the ipsilateral ear; if the ipsilateral ear is stimulated below threshold, the contralateral ear performs near 100%. However, if the intensity of speech in the ipsilateral ear is increased above SRT, the contralateral scores drop markedly as intelligibility increases in the ipsilateral ear. This 'trade off' does not occur when noise is the competing stimulus. This phenomenon is interpreted as a sign of 'speech identification' and is suggested as a potential technique for differentiating speech from nonspeech elements. [ABSTRACT FROM AUTHOR]