Acoustical regularities in infant-directed vocalizations worldwide

• Published in: The Journal of the Acoustical Society of America 2019-03, Vol.145 (3), p.1766-1766
• Main Authors: Moser, Cody J., Lee-Rubin, Harry, Collaboration, Infant-Directed Vocalizations, Bainbridge, Constance M., Atwood, Stephanie, Krasnow, Max M., Mehr, Samuel A.
• Format: Article
• Language: English
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.5101469

Adults often differentiate their song and speech between infants and other adults. Why? Is this a product of just some cultures or does it reflect a universal part of human vocal communication and human cognition? On the latter hypothesis, infant directed-song might regularly exhibit certain features across cultures, including high redundancy and repetition, high signal-to-noise ratios, and superb vowel prolongation and stability compared to adult-directed song. We built a corpus of 1614 recordings of infant- and adult-directed singing and speech produced by 411 people living in 20 societies, including hunter-gatherers and subsistence farmers. Each participant provided examples of each of the four vocalization types. Using exploratory and confirmatory analyses, we show that the acoustical features of infant-directed song and speech are universally distinct from adult-directed song and speech, especially in terms of the phonetic space of their formants, their general rhythmic structure, and their pitch range attributes.