You and your baby are now well out of the newborn period. Your baby has become much more interactive and responds more predictably to your cues. You can actually enjoy more playtime with baby as he reaches out for toys, shakes rattles, and squeals in delight at your smiling face. Here is a guide to help you understand the many changes that come at this age and to help your baby grow and develop through these months. Additionally, here is what you should expect at your four-month visit to the pediatrician.