Soli S D
J Acoust Soc Am. 1983 Jun;73(6):2150-65. doi: 10.1121/1.389539.
The influence of spectral cues on discrimination peaks in the region of the phonetic voicing boundary was examined. The discriminability of voice onset time (VOT) differences of the same temporal magnitude was assessed using stimuli from labial and velar consonant-vowel VOT continua that differed in the timing of spectral changes associated with the first formant (F1) transition, and in the location of the phonetic boundary. Subjects were initially given labeling tests and fixed-standard AX and all-step discrimination tests on both series. Half the subjects then received all-step discrimination training on one series and half received training on the other series. Finally, all subjects were again given the labeling and discrimination tests on both series. Just noticeable differences (jnds) in VOT were estimated from the all-step functions before and after training. Initial jnds showed that VOT discrimination was most accurate around the voicing boundary on the two continua, where differences in F1 onset frequency accompany variations in VOT. jnds on both series decreased significantly after training, although these regions of greater sensitivity remained. No evidence was seen of increased sensitivity around +/- 20-ms VOT, as expected if auditory processing constraints were influencing temporal order judgments. Comparisons of post-training jnds within and across series indicated that spectral components of VOT, primarily F1 onset frequency differences, exert a substantial influence on discrimination, and, along with other spectral cues provided by source differences at stimulus onset, can account for the discontinuities in discrimination often reported in research with VOT continua. Large phonetic effects also were seen in the initial performance of all subjects: jnds decreased consistently as standards drew nearer the voicing boundary. However, these effects were absent in the final jnds for most subjects. Implications of these findings for the understanding of basic auditory and attentional processes in speech perception are discussed.
研究了频谱线索对语音浊音边界区域辨别峰值的影响。使用来自唇音和软腭辅音-元音VOT连续统的刺激来评估相同时间幅度的语音起始时间（VOT）差异的可辨别性，这些刺激在与第一共振峰（F1）过渡相关的频谱变化时间以及语音边界位置上有所不同。首先让受试者对两个系列进行标记测试以及固定标准的AX和全步辨别测试。然后，一半受试者在一个系列上接受全步辨别训练，另一半在另一个系列上接受训练。最后，再次让所有受试者对两个系列进行标记和辨别测试。根据训练前后的全步函数估计VOT中的恰可察觉差异（jnds）。初始jnds表明，在两个连续统的浊音边界附近，VOT辨别最为准确，此时F1起始频率的差异伴随着VOT的变化。训练后两个系列的jnds均显著下降，尽管这些更高敏感度的区域仍然存在。未发现如预期的在±20毫秒VOT附近敏感度增加的证据，即如果听觉处理限制影响时间顺序判断的话。系列内和系列间训练后jnds的比较表明，VOT的频谱成分，主要是F1起始频率差异，对辨别有重大影响，并且与刺激起始时声源差异提供的其他频谱线索一起，可以解释在VOT连续统研究中经常报道的辨别不连续性。在所有受试者的初始表现中也观察到了较大的语音效应：随着标准接近浊音边界，jnds持续下降。然而，对于大多数受试者来说，最终的jnds中没有这些效应。讨论了这些发现对理解语音感知中基本听觉和注意力过程的意义。
