Newborns don't know that their hands are a part of them: baby may use one hand to play with the other, almost as though they were toys. A toy that can be held, like a rattle, helps baby understand who those little hands belong to. When the rattle produces sounds after a shake from baby, eyes and ears locate the noise and baby makes an exciting discovery: baby's hand shakes the rattle, and that's what creates the new sound!

For the first six months, babies use their eyes and hands separately—baby fingers things without looking at them and looks at things without touching them. And as long as looking at an object and touching that object remain separate in baby's mind, your baby will stay a passive observer of the world, instead of an active participant in its goings-on. One of the biggest challenges of the first year of life is developing eye-hand coordination. In order to fully explore the world, your little shaker and mover must put these two activities—looking and touching—together. Although the subtle skill of developing hand control often receives second billing to the glamour of walking, it's just as vital. The child who is good with a ball or a hammer is one whose hand–eye coordination is well developed; good drivers also have good eye-hand coordination. Offering appropriate kinds of play as soon as your baby's ready will speed your child's sense of accomplishment and learning, and contribute to success in future hand–manipulating skills, such as sports, musical training, or anything that requires physical interaction.