Distress vocalizations are fundamental for survival, and both sonic and ultrasonic components of such vocalizations are preserved phylogenetically among many mammals. On this basis, we hypothesized that ultrasonic inaudible components of the acoustic signal might play a heretofore hidden role in humans as well. By investigating the human distress vocalization (infant cry), here we show that, similar to other species, the human infant cry contains ultrasonic components that modulate haemodynamic responses in mothers, without the mother being consciously aware of those modulations. In two studies, we measured the haemodynamic activity in the breasts of mothers while they were exposed to the ultrasonic components of infant cries. Although mothers were not aware of ultrasounds, the presence of the ultrasounds in combination with the audible components increased oxygenated haemoglobin concentration in the mothers' breast region. This modulation was observed only when the body surface was exposed to the ultrasonic components. These findings provide the first evidence indicating that the ultrasonic components of the acoustic signal play a role in human mother-infant interaction.

中文翻译：

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人类婴儿哭声中的听不见的成分会影响母亲乳房区域的血流动力学反应。


遇险发声是生存的基础，这种发声的声音和超声波成分在许多哺乳动物的系统发育中都得到了保留。在此基础上，我们假设声学信号中的超声波听不见的成分也可能在人类身上发挥着迄今为止隐藏的作用。通过研究人类遇险发声（婴儿哭声），我们发现，与其他物种类似，人类婴儿的哭声包含调节母亲血液动力学反应的超声波成分，而母亲并没有意识到这些调节。在两项研究中，我们测量了母亲暴露于婴儿哭声的超声波成分时乳房的血流动力学活动。尽管母亲们不知道超声波，但超声波与声音成分的结合增加了母亲乳房区域的氧合血红蛋白浓度。仅当身体表面暴露于超声波成分时才能观察到这种调制。这些发现提供了第一个证据，表明声信号的超声波成分在人类母婴互动中发挥作用。