Melodic Contours of Maternal Humming to Preterm Infants in Skin-To-Skin Contact: Impact of the Infant’s Gender

Since birth infants are sensitive to the temporal structure and melodic contours of infant-directed speech and singing. Infant-directed singing enhances attention and plays a crucial role in sustaining an infant’s moderate arousal state. Nevertheless, the characteristics of the melodic contours of maternal humming to preterm infants are not known. There is also a need to investigate the influence of infant’s gender on the melodic contours of maternal humming. Goals: 1) to identify the melodic contours of maternal humming directed to preterm infants in skin-to-skin contact, 2) to analyze if the melodic contour types have an impact on infants’ overlapping vocalizations, 3) to observe the differences between the melodic contours of maternal humming directed to female and to male infants and 4) to identify the differences between the overlapping vocalizations during maternal humming directed to female and male infants. Method: Preterm mothers (n = 36) were invited to speak and to hum to their preterm infants after a silent baseline period. Microanalysis of the melodic contours was conducted based on identified temporal units of maternal humming. Results: A predominance of sinusoidal, bell-shaped and rising melodic contours was observed. Significant differences were found in infants’ overlapping vocalizations according with the melodic contours styles. Moreover, more overlapping vocalizations in female than in male infants were found during rising, U-bell-shaped and sinusoidal phrases. Furthermore, higher frequencies of falling and sinusoidal contours were observed in maternal humming directed to male infants while higher frequencies of rising contours were found in humming directed to female infants. Conclusions: The melodic style of maternal humming as well the infants’ overlapping vocalizations produced during the humming can be influenced by infant’s gender. These results underline how the mother’s vocal behavior is influenced by infant’s characteristics from the get-go.