Contralateral noise effects on the perception of manner for initial voiceless stops
Richard E. Pastore, Crystle B. Morris, Robert J. Logan, Jody Kaplan Layer · The Journal of the Acoustical Society of America · 1985
Several years ago, we discovered that the perception of an initial voiceless consonant “p” in a monaural CV syllable could be altered by a burst of noise roughly coincident (+/−50 ms) with the onset of the stop. These noise-induced misperceptions were found only when the noise was contralateral to the consonant and approximately equal in intensity (+/−20 dB). We later found that the effect was highly dependent upon the subsequent vowel. Our current research investigates effects of the (a) following vowel, (b) linguistic property of the stimulus (actual word versus nonsense word), (c) the task of the subject (identification of word versus initial consonant), and (d) presentation of no-noise control trials (randomly mixed with noise trials versus blocked separately). The natural token stimuli were spoken by a male linguist, and digitized for later computer synthesis at equal average intensities. We found systematic errors in the perception of “p” as “t” under certain conditions, the perception of “t” as “p” for other conditions and, under some conditions, no errors. Differences also were found for the two types of no-noise control. The possible basis for these noise-induced misperceptions will be discussed. [Research supported by NSF grant BNS-83-02873.]