Lively S E, Pisoni D B, Van Summers W, Bernacki R H
Department of Psychology, Indiana University, Bloomington 47405.
J Acoust Soc Am. 1993 May;93(5):2962-73. doi: 10.1121/1.405815.
The present investigation examined the effects of cognitive workload on speech production. Workload was manipulated by having talkers perform a compensatory visual tracking task while speaking test sentences of the form "Say hVd again." Acoustic measurements were made to compare utterances produced under workload with the same utterances produced in a control condition. In the workload condition, some talkers produced utterances with increased amplitude and amplitude variability, decreased spectral tilt and F0 variability and increased speaking rate. No changes in F1, F2, or F3 were observed across conditions for any of the talkers. These findings indicate both laryngeal and sublaryngeal adjustments in articulation, as well as modifications in the absolute timing of articulatory gestures. The results of a perceptual identification experiment paralleled the acoustic measurements. Small but significant advantages in intelligibility were observed for utterances produced under workload for talkers who showed robust changes in speech production. Changes in amplitude and amplitude variability for utterances produced under workload appeared to be the major factor controlling intelligibility. The results of the present investigation support the assumptions of Lindblom's ["Explaining phonetic variation: A sketch of the H&H theory," in Speech Production and Speech Modeling (Klewer Academic, The Netherlands, 1990)] H&H model: Talkers adapt their speech to suit the demands of the environment and these modifications are designed to maximize intelligibility.
本研究考察了认知负荷对言语产生的影响。通过让说话者在说出“再说一遍hVd”这种形式的测试句子时执行一项补偿性视觉跟踪任务来操纵负荷。进行声学测量以比较在负荷条件下产生的话语与在对照条件下产生的相同话语。在负荷条件下，一些说话者产生的话语具有增大的振幅和振幅变异性、减小的频谱倾斜度和基频变异性以及提高的说话速率。对于任何说话者，在不同条件下均未观察到第一共振峰（F1）、第二共振峰（F2）或第三共振峰（F3）有变化。这些发现表明在发音过程中喉部和喉部以下部位都进行了调整，以及发音动作的绝对时间安排也有改变。一项感知识别实验的结果与声学测量结果相似。对于在言语产生方面有显著变化的说话者，在负荷条件下产生的话语在可懂度方面具有虽小但显著的优势。在负荷条件下产生的话语的振幅和振幅变异性变化似乎是控制可懂度的主要因素。本研究结果支持林德布洛姆（Lindblom）在《语音产生与语音建模》（荷兰Klewer学术出版社，1990年）中提出的H&H模型的假设：说话者会调整他们的言语以适应环境需求，并且这些调整旨在使可懂度最大化。
