Wang Ningyuan, Oxenham Andrew J
Department of Psychology, University of Minnesota, Minneapolis, Minnesota 55455.
J Acoust Soc Am. 2014 Sep;136(3):1237. doi: 10.1121/1.4892771.
Spectral contrast effects may help "normalize" the incoming sound and produce perceptual constancy in the face of the variable acoustics produced by different rooms, talkers, and backgrounds. Recent studies have concentrated on the after-effects produced by the long-term average power spectrum. The present study examined contrast effects based on spectral motion, analogous to visual-motion after-effects. In experiment 1, the existence of spectral-motion after-effects with word-length inducers was established by demonstrating that the identification of the direction of a target spectral glide was influenced by the spectral motion of a preceding inducer glide. In experiment 2, the target glide was replaced with a synthetic sine-wave speech sound, including a formant transition. The speech category boundary was shifted by the presence and direction of the inducer glide. Finally, in experiment 3, stimuli based on synthetic sine-wave speech sounds were used as both context and target stimuli to show that the spectral-motion after-effects could occur even with inducers with relatively short speech-like durations and small frequency excursions. The results suggest that spectral motion may play a complementary role to the long-term average power spectrum in inducing speech context effects.
频谱对比效应可能有助于“规范化”传入声音，并在面对不同房间、说话者和背景所产生的可变声学环境时产生感知恒常性。近期研究集中于长期平均功率谱所产生的后效应。本研究考察了基于频谱运动的对比效应，类似于视觉运动后效应。在实验1中，通过证明目标频谱滑动方向的识别受到先前诱导性滑动的频谱运动的影响，证实了存在带有词长诱导物的频谱运动后效应。在实验2中，目标滑动被一个合成正弦波语音所取代，该语音包括一个共振峰过渡。诱导性滑动的存在和方向使语音类别边界发生了偏移。最后，在实验3中，基于合成正弦波语音的刺激被用作背景刺激和目标刺激，以表明即使使用具有相对较短语音样持续时间和较小频率偏移的诱导物，也可能出现频谱运动后效应。结果表明，频谱运动在诱导语音背景效应方面可能对长期平均功率谱起到补充作用。
