During your baby’s first four months, did you have doubts that she really understood much that was happening around her? This parental reaction is not surprising. After all, although you knew when she was comfortable and uncomfortable, she probably showed few signs of actually thinking. But studies show that from the minute your baby is born, she is learning about the world around her, even though it may not be apparent to you or others. Now, as her memory and attention span increase, you’ll start to see evidence that she’s not only absorbing information but also applying it to her day-to-day activities.
During this period, one of the most important concepts she’ll refine is the principle of cause and effect. She’ll probably stumble on this notion by accident somewhere between four and five months. Perhaps while kicking her mattress, she’ll notice the crib shaking. Or maybe she’ll realize that her rattle makes a noise when she hits or waves it. Once she understands that she can cause these interesting reactions, she’ll continue to experiment with other ways to make things happen.
Your baby will quickly discover that some things, such as bells and keys, make interesting sounds when moved or shaken. When she bangs certain things on the table or drops them on the floor, she’ll start a chain of responses from her audience, including funny faces, groans, and other reactions that may lead to the reappearance—or disappearance—of the object. Before long, she’ll begin dropping things intentionally to see you pick them up. As annoying as this may be at times, it’s one important way for her to learn about cause and effect and her personal ability to influence her environment.
It’s important that you give your child the objects she needs for these experiments and encourage her to test her “theories.” But make sure that everything you give her to play with is unbreakable, lightweight, and large enough that she can’t possibly swallow it. If you run out of the usual toys or she loses interest in them, plastic or wooden spoons, unbreakable cups, and jar or bowl lids and boxes are endlessly entertaining and inexpensive.
Another major discovery that your baby will make toward the end of this period is that objects continue to exist when they’re out of her sight—a principle called object permanence. During her first few months, she assumed that the world consisted only of things that she could see. When you left her room, she assumed you vanished; when you returned, you were a whole new person to her. In much the same way, when you hid a toy under a cloth or a box, she thought it was gone for good and wouldn’t bother looking for it. But sometime after four months, she’ll begin to realize that the world is more permanent than she thought. You’re the same person who greets her every morning. Her teddy bear on the floor is the same one that was in bed with her the night before. The block that you hid under the can did not actually vanish after all. By playing hiding games like peekaboo and observing the comings and goings of people and things around her, your baby will continue to learn about object permanence for many months to come.