Valente Daria, Magnard Cecile, Koutseff Alexis, Patural Hugues, Chauleur Celine, Reby David, Pisanski Katarzyna
Department of Life Sciences and Systems Biology, University of Turin, Torino 10123, Italy.
Lucie Hussel Hospital, Maternity Ward, Montée du Dr Chapuis, Vienne 38200, France.
Philos Trans R Soc Lond B Biol Sci. 2025 Apr 3;380(1923):20240009. doi: 10.1098/rstb.2024.0009.
Nonlinear acoustic phenomena (NLP) likely facilitate the expression of distress in animal vocalizations, making calls perceptually rough and hard to ignore. Yet, their function in adult human vocal communication remains poorly understood. Here, to examine the production and perception of acoustic correlates of pain in spontaneous human nonverbal vocalizations, we take advantage of childbirth-a natural context in which labouring women typically produce a range of highly evocative loud vocalizations, including moans and screams-as they experience excruciating pain. We combine acoustic analyses of these real-life pain vocalizations with psychoacoustic experiments involving the playback of natural and synthetic calls to both naïve and expert listeners. We show that vocalizations become acoustically rougher, higher in fundamental frequency (pitch), less stable, louder and longer as child labour progresses, paralleling a rise in women's self-assessed pain. In perception experiments, we show that both naïve listeners and obstetric professionals assign the highest pain ratings to vocalizations produced in the final expulsion phase of labour. Experiments with synthetic vocal stimuli confirm that listeners rely largely on nonlinear phenomena to assess pain. Our study confirms that nonlinear phenomena communicate intense, pain-induced distress in humans, consistent with their widespread function to signal distress and arousal in vertebrate vocal signals.This article is part of the theme issue 'Nonlinear phenomena in vertebrate vocalizations: mechanisms and communicative functions'.
非线性声学现象（NLP）可能有助于动物发声中痛苦情绪的表达，使叫声在感知上显得粗糙且难以忽视。然而，它们在成年人类语音交流中的功能仍知之甚少。在此，为了研究自发的人类非语言发声中疼痛的声学关联的产生和感知，我们利用分娩这一自然情境——在分娩过程中，劳动妇女在经历极度疼痛时通常会发出一系列极具感染力的大声呼喊，包括呻吟和尖叫。我们将对这些现实生活中疼痛发声的声学分析与心理声学实验相结合，该实验涉及向新手和专家听众播放自然和合成的叫声。我们发现，随着分娩进程的推进，发声在声学上变得更粗糙、基频（音高）更高、更不稳定、更大声且持续时间更长，这与女性自我评估的疼痛加剧情况相平行。在感知实验中，我们表明新手听众和产科专业人员都将分娩最后排出阶段发出的声音评为最高疼痛等级。对合成语音刺激的实验证实，听众在很大程度上依赖非线性现象来评估疼痛。我们的研究证实，非线性现象在人类中传达强烈的、由疼痛引起的痛苦情绪，这与其在脊椎动物发声信号中广泛的传达痛苦和唤醒情绪的功能相一致。本文是主题为“脊椎动物发声中的非线性现象：机制与交流功能”的一部分。
