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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人类婴儿啼哭的听不见的成分会影响母亲的乳房区域的血流动力学反应。

遇险发声是生存的基础，在许多哺乳动物中，这种发声的声音和超声成分在系统发育上都得到了保留。在此基础上，我们假设声信号的超声不可听成分也可能在人类中起迄今隐藏的作用。通过调查人类的痛苦发声（婴儿啼哭），我们在这里显示出，与其他物种相似，人类婴儿啼哭包含超声成分，这些成分调节母亲的血液动力学反应，而母亲没有意识地意识到这些调节。在两项研究中，我们测量了母亲暴露于婴儿啼哭的超声成分时其乳房的血液动力学活性。尽管母亲不了解超声波，超声波与可听见成分的结合会增加母亲乳房区域的氧化血红蛋白浓度。仅当身体表面暴露于超声成分时才能观察到这种调制。这些发现提供了第一个证据，表明声信号的超声成分在人类母婴互动中起作用。