Distinctive messages in infant-directed lullabies and play songs

Mothers were recorded singing a song of their choice in both a lullaby style and a play-song style to their 6-month-olds. Adult raters identified the play-song-style and lullaby-style versions with 100% accuracy. Play-song-style renditions were rated as being more brilliant, clipped, and rhythmic and as having more smiling and more prominent consonants. Lullaby-style renditions were characterized as being more airy, smooth, and soothing. Adults observed videotapes (without sound) of 6-month-olds listening to alternating lullaby-style and play-song-style trials and performed at above chance levels when determining which music the infants were hearing. Coding analyses revealed that infants focused their attention more toward themselves during lullaby-style trials and more toward the external world during play-song-style trials. These results suggest that singing may be used to regulate infants' states and to communicate emotional information.