Dipartimento di Psicologia e Scienze Cognitive, Università degli Studi di Trento, Trento, Italy.
Dipartimento di Psicologia, Università degli Studi di Milano-Bicocca, Milano, Italy.
Eur J Neurosci. 2022 Aug;56(3):4086-4106. doi: 10.1111/ejn.15730. Epub 2022 Jun 23.
The present study investigated whether listeners can form abstract voice representations while ignoring constantly changing phonological information and if they can use the resulting information to facilitate voice change detection. Further, the study aimed at understanding whether the use of abstraction is restricted to the speech domain or can be deployed also in non-speech contexts. We ran an electroencephalogram (EEG) experiment including one passive and one active oddball task, each featuring a speech and a rotated speech condition. In the speech condition, participants heard constantly changing vowels uttered by a male speaker (standard stimuli) which were infrequently replaced by vowels uttered by a female speaker with higher pitch (deviant stimuli). In the rotated speech condition, participants heard rotated vowels, in which the natural formant structure of speech was disrupted. In the passive task, the mismatch negativity was elicited after the presentation of the deviant voice in both conditions, indicating that listeners could successfully group together different stimuli into a formant-invariant voice representation. In the active task, participants showed shorter reaction times (RTs), higher accuracy and a larger P3b in the speech condition with respect to the rotated speech condition. Results showed that whereas at a pre-attentive level the cognitive system can track pitch regularities while presumably ignoring constantly changing formant information both in speech and in rotated speech, at an attentive level the use of such information is facilitated for speech. This facilitation was also testified by a stronger synchronisation in the theta band (4-7 Hz), potentially pointing towards differences in encoding/retrieval processes.
本研究旨在探讨在忽略不断变化的语音信息的情况下，听者是否能够形成抽象的语音表征，以及他们是否可以利用由此产生的信息来促进语音变化检测。此外，本研究旨在了解抽象的使用是否仅限于言语领域，还是也可以在非言语情境中运用。我们进行了一项脑电图 (EEG) 实验，包括一个被动和一个主动的Oddball 任务，每个任务都有一个言语和一个旋转言语条件。在言语条件下，参与者听到一个男性说话者发出的不断变化的元音（标准刺激），这些元音偶尔会被一个女性说话者发出的更高音调的元音（偏离刺激）取代。在旋转言语条件下，参与者听到的是旋转的元音，其中言语的自然共振峰结构被打乱了。在被动任务中，在两种条件下呈现偏离语音后，都诱发出了失匹配负波，表明听者能够成功地将不同的刺激组合成一个共振峰不变的语音表征。在主动任务中，与旋转言语条件相比，参与者在言语条件下表现出更短的反应时间 (RT)、更高的准确性和更大的 P3b。结果表明，在非注意水平上，认知系统可以在语音和旋转语音中跟踪音高规律，而忽略不断变化的共振峰信息，而在注意水平上，这种信息的利用更有利于语音。这种促进作用也在θ波段（4-7 Hz）的更强同步中得到了证明，这可能表明了编码/检索过程的差异。
