Human Maternal Vocalizations to Infants as Biologically Relevant Signals: An Evolutionary Perspective

Abstract

When talking to infants, human mothers use vocal patterns that are unusual by the standards of normal conversation. Mothers, as well as fathers and adults who are not parents, speak consistently more slowly and with higher pitch when interacting with infants, in smooth, exaggerated intonation contours quite unlike the choppy and rapid-fire speech patterns used when addressing adults. To praise an infant, mothers typically use wide range pitch contours with a rise-fall pattern. To elicit an infant ’s attention, they also use wide-range contours, but often ending with rising pitch. When soothing an infant, mothers tend to use long, smooth, falling pitch contours, in marked contrast to the short, sharp intonation patterns used in warning or disapproval. This use of exaggerated and stereotyped vocal patterns in mothers ‘ speech to infants has been observed in numerous European, Asian, and African cultures and appears to be a universal human parental behavior.