Sharma A, Kraus N, McGee T, Carrell T, Nicol T
Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL 60208.
Electroencephalogr Clin Neurophysiol. 1993 Jan-Feb;88(1):64-71. doi: 10.1016/0168-5597(93)90029-o.
The concept of categorical perception of speech and speech-like sounds has been central to models of speech perception for decades. Event-related potentials (ERPs) provide a neurophysiologic perspective of this important phenomenon. In the present experiment the mismatch negativity (MMN) event-related potential, which is sensitive to fine acoustic differences, was recorded in adults. Of interest was whether the MMN reflects the acoustic or categorical perception of speech. The MMN was elicited by stimulus pairs (along a continuum varying in place of articulation from /da/ to /ga/) which had been identified as the same phoneme /da/ (within category condition) and as different phonemes /da/ and /ga/ (across categories condition). The acoustic differences between these two pairs of stimuli were equivalent. The MMN was observed in all subjects both in the within and across category conditions. Furthermore, the MMN did not differ in latency, amplitude or area within and across categories. That is, the MMN indicated equal discrimination both across and within categories. These results suggest that the MMN appears to reflect the processing of acoustic aspects of the speech stimulus, but not phonetic processing into categories. The MMN appears to be an extremely sensitive electrophysiologic index of minimal acoustic differences in speech stimuli.
几十年来，语音和类语音声音的范畴知觉概念一直是语音感知模型的核心。事件相关电位（ERP）为这一重要现象提供了神经生理学视角。在本实验中，对成年人记录了对细微声学差异敏感的失匹配负波（MMN）事件相关电位。感兴趣的是MMN是否反映了语音的声学或范畴知觉。MMN由刺激对诱发（沿着从/da/到/ga/发音部位连续变化），这些刺激对被确定为相同音素/da/（类别内条件）和不同音素/da/和/ga/（跨类别条件）。这两对刺激之间的声学差异是等同的。在类别内和跨类别条件下，所有受试者均观察到了MMN。此外，MMN在类别内和跨类别之间的潜伏期、波幅或面积没有差异。也就是说，MMN表明在跨类别和类别内具有同等的辨别力。这些结果表明，MMN似乎反映了语音刺激声学方面的加工，而不是语音刺激的范畴加工。MMN似乎是语音刺激中最小声学差异的极其敏感的电生理指标。
