Think back to the first song you can remember. For many people it is a lullaby hummed at bedtime, a nursery rhyme repeated in the car, or a silly tune a grandparent sang while cooking. Songs like these seem simple, almost too simple to matter. Yet music is one of the oldest ways that people have comforted, taught and connected with their children, and in cultures all around the world, adults sing to babies without being told to do so. There is good reason for that instinct, a