 Infants exhibit a natural preference for infant-directed over non-infant-directed lullabies and their own mothers' voice over that of another female.Much research has been generated on the role of lullabies in nurturing caregiving bonds between mother and child.Mothers who sing lullabies to their infants engage in a bonding activity that actually alters the underlying neural structure of the infant brain such that the infant becomes "tuned" into music and its association with parental affiliation.