Department of Psychology, Harvard University, Cambridge, MA, USA.
Haskins Laboratories, Yale University, New Haven, CT, USA.
Nat Hum Behav. 2022 Nov;6(11):1545-1556. doi: 10.1038/s41562-022-01410-x. Epub 2022 Jul 18.
When interacting with infants, humans often alter their speech and song in ways thought to support communication. Theories of human child-rearing, informed by data on vocal signalling across species, predict that such alterations should appear globally. Here, we show acoustic differences between infant-directed and adult-directed vocalizations across cultures. We collected 1,615 recordings of infant- and adult-directed speech and song produced by 410 people in 21 urban, rural and small-scale societies. Infant-directedness was reliably classified from acoustic features only, with acoustic profiles of infant-directedness differing across language and music but in consistent fashions. We then studied listener sensitivity to these acoustic features. We played the recordings to 51,065 people from 187 countries, recruited via an English-language website, who guessed whether each vocalization was infant-directed. Their intuitions were more accurate than chance, predictable in part by common sets of acoustic features and robust to the effects of linguistic relatedness between vocalizer and listener. These findings inform hypotheses of the psychological functions and evolution of human communication.
当与婴儿互动时，人类通常会改变他们的言语和歌声，这些改变被认为有助于交流。基于跨物种声音信号数据的人类育儿理论预测，这种改变应该是全球性的。在这里，我们展示了跨文化的婴儿指向和成人指向的发声之间的声学差异。我们收集了 21 个城市、农村和小规模社会中 410 个人的 1615 段婴儿指向和成人指向的言语和歌声录音。仅从声学特征就可以可靠地分类婴儿指向性，不同语言和音乐中的婴儿指向性的声学特征模式一致，但存在差异。然后，我们研究了听众对这些声学特征的敏感性。我们通过一个英语网站招募了来自 187 个国家的 51065 人，播放这些录音，让他们猜测每个发声是婴儿指向还是成人指向。他们的直觉比随机猜测更准确，部分可以通过共同的声学特征来预测，并且不受发声者和听众之间语言相关性的影响。这些发现为人类交流的心理功能和进化提供了假设。
