The impact of mother's mental health, infant characteristics and war trauma on the acoustic features of infant-directed singing.

Infant-directed singing (IDSi) is a natural means of dyadic communication that contributes to children's mental health by enhancing emotion expression, close relationships, exploration and learning. Therefore, it is important to learn about factors that impact the IDSi. This study modeled the mother- (mental health), infant- (emotional responses and health status) and environment (war trauma)-related factors influencing acoustic IDSi features, such as pitch (F0) variability, amplitude and vibration and the F0 contour of shapes and movements. The participants were 236 mothers and infants from Gaza, the Occupied Palestinian Territories. The mothers reported their mental health problems, infants' emotionality and regulation skills, and, along with pediatric checkups, illnesses and disorders, as well as traumatic war events that were also photo documented. The results showed that the mothers' mental health problems and infants' poor health status were associated with IDSi, characterized by narrow and lifeless amplitude and vibration, and poor health was also associated with the limited and rigid shapes and movements of F0 contours. Traumatic war events were associated with flat and narrow F0 variability and the monotonous and invariable resonance and rhythm of IDSi formants. The infants' emotional responses did not impact IDSi. The potential of protomusical singing to help war-affected dyads is discussed.