Expressive timing and dynamics in infant-directed and non-infant-directed singing
AbstractExpressive variations in timing and dynamics were examined in infant-directed performances of by mothers and in non-infant-directed performances by non-mothers. Mothers sang to their infants, and non-mothers sang informally on their own. Acoustic analyses revealed that infant-directed performances had fewer expressive variations in timing such as rubato and ritardando than did non-infant-directed performances. By contrast, infant-directed performances exhibited a greater dynamic range than non-infant-directed performances. Moreover, relations between pitch height and amplitude were more tightly coupled in infant-directed than in non-infant-directed performances. We interpret mothers’ liberal modulation of dynamics and their limited modulation of timing as fine-tuning to the perceptual, emotional, and informational needs of infants.