Kiefte Michael, Kluender Keith R
School of Human Communication Disorders, Dalhousie University, Halifax, Nova Scotia B3H 1R2, Canada.
J Acoust Soc Am. 2008 Jan;123(1):366-76. doi: 10.1121/1.2804951.
Several experiments are described in which synthetic monophthongs from series varying between /i/ and /u/ are presented following filtered precursors. In addition to F(2), target stimuli vary in spectral tilt by applying a filter that either raises or lowers the amplitudes of higher formants. Previous studies have shown that both of these spectral properties contribute to identification of these stimuli in isolation. However, in the present experiments we show that when a precursor sentence is processed by the same filter used to adjust spectral tilt in the target stimulus, listeners identify synthetic vowels on the basis of F(2) alone. Conversely, when the precursor sentence is processed by a single-pole filter with center frequency and bandwidth identical to that of the F(2) peak of the following vowel, listeners identify synthetic vowels on the basis of spectral tilt alone. These results show that listeners ignore spectral details that are unchanged in the acoustic context. Instead of identifying vowels on the basis of incorrect acoustic information, however (e.g., all vowels are heard as /i/ when second formant is perceptually ignored), listeners discriminate the vowel stimuli on the basis of the more informative spectral property.
文中描述了几个实验，在这些实验中，在经过滤波的前导音之后呈现出从/i/到/u/变化的合成单元音系列。除了第二共振峰（F(2)）外，目标刺激通过应用一个提高或降低较高共振峰振幅的滤波器来改变频谱倾斜度。先前的研究表明，这两种频谱特性都有助于单独识别这些刺激。然而，在本实验中我们表明，当一个前导音句子由用于调整目标刺激频谱倾斜度的相同滤波器处理时，听众仅根据F(2)来识别合成元音。相反，当前导音句子由一个中心频率和带宽与后续元音的F(2)峰值相同的单极滤波器处理时，听众仅根据频谱倾斜度来识别合成元音。这些结果表明，听众会忽略在声学语境中不变的频谱细节。然而，听众并非基于错误的声学信息来识别元音（例如，当第二共振峰在感知上被忽略时，所有元音都被听成/i/），而是根据信息量更大的频谱特性来区分元音刺激。
