Babies come into this world with small heads and incomplete brains, with survival and growth dependent on an extended fourth trimester outside the mother’s body, but close to it. The newborn baby must have loving care to begin to be able to coordinate her senses, emotions, thoughts, and body functions, as well as relationships with people in her environment. Babies do this by copying into their brain’s highways the mind and body habits they sense in their caregiver and others they love and trust. They develop these qualities by having frequent and repeated affectionate and playful interactions with their caregiver. These are often initiated by the baby, taking turns to imitate each other’s touch, motions, facial expressions, and sounds.