Gordon P C, Eberhardt J L, Rueckl J G
Department of Psychology, Harvard University, Cambridge, MA 02138.
Cogn Psychol. 1993 Jan;25(1):1-42. doi: 10.1006/cogp.1993.1001.
Four experiments addressing the role of attention in phonetic perception are reported. The first experiment shows that the relative importance of two cues to the voicing distinction changes when subjects must perform an arithmetic distractor task at the same time as identifying a speech stimulus. The contribution of voice onset time to phonetic labeling decreases when subjects are distracted, while that of FO onset frequency increases. The second experiment shows a similar pattern for two cues to the distinction between the vowels /i/ (as in "beat") and /I/ (as in "bit"). Under low attention conditions, formant pattern has a smaller effect on phonetic labeling while vowel duration has a larger effect. Together these experiments indicate that careful attention to speech perception is necessary for strong acoustic cues (voice-onset time and formant patterns) to achieve their full impact on phonetic labeling, while weaker acoustic cues (FO onset frequency and vowel duration) achieve their full impact on phonetic labeling without close attention. Experiment 3 shows that this pattern is obtained when the distractor task places little demand on verbal short-term memory. Experiment 4 provides a data set for testing formal models of the role of attention in speech perception. Attention is shown to influence the signal-to-noise ratio in the phonetic encoding of acoustic cues; the sustained phonetic contribution of weak cues without close attention stems from reduced competition from strong cues. This principle is instantiated in a network model in which the role of attention is to reduce noise in the phonetic encoding of acoustic cues. Implications of this work for understanding speech perception and general theories of the role of attention in perception are discussed.
本文报告了四项关于注意力在语音感知中作用的实验。第一个实验表明，当受试者在识别语音刺激的同时必须执行算术干扰任务时，两种用于区分浊音的线索的相对重要性会发生变化。当受试者分心时，语音起始时间对语音标记的贡献会降低，而基频起始频率的贡献会增加。第二个实验显示了区分元音/i/（如“beat”中的发音）和/I/（如“bit”中的发音）的两种线索的类似模式。在低注意力条件下，共振峰模式对语音标记的影响较小，而元音时长的影响较大。这些实验共同表明，要使强声学线索（语音起始时间和共振峰模式）对语音标记产生充分影响，需要仔细关注语音感知，而弱声学线索（基频起始频率和元音时长）在不密切关注的情况下就能对语音标记产生充分影响。实验3表明，当干扰任务对言语短期记忆的要求较低时，会出现这种模式。实验4提供了一个数据集，用于测试注意力在语音感知中作用的形式模型。研究表明，注意力会影响声学线索语音编码中的信噪比；弱线索在不密切关注的情况下持续产生语音贡献，源于强线索竞争的减少。这一原理在一个网络模型中得到体现，其中注意力的作用是降低声学线索语音编码中的噪声。本文还讨论了这项工作对理解语音感知以及注意力在感知中作用的一般理论的意义。
