During the first few months of a newborn’s life, the entire world as she knows it is what is before her eyes. As soon as something disappears out of her eyesight – it’s as if it never existed. Gradually the world opens up to encompass what is outside the range of her senses, and she begins to think and imagine people and objects that she doesn’t see in front of her. This is object permanence – the ability to understand that objects still exist after they are no longer in sight.

Object permanence is an important element in a baby's intellectual and emotional development. As soon as a baby is able to conjure up an image of a person or object in her mind, she is also capable of cognitive thought: remembering, imagining, deductive reasoning and planning. She is no longer dependent on trial and error to solve problems. She is now capable of bringing up an image in her mind of an object that is no longer in sight, say a bottle, remember where she saw it last, and set out to find it. In other words, she can use the images in her mind before taking action, which is the first step in being able to plan and understand the concept of expectations for the future based on the past.

Out of Sight, IN the Mind

The popular expression "out of sight, out of mind" is more than just an expression. It is a truism for the first months of a baby's life. What he can’t see simply doesn’t exist for him. If a newborn is looking at a rattle and we take it away and replace it with something else, he will not search for the rattle. It’s as if he has forgotten it ever existed.

When a baby is approximately eight months old, an interesting and dramatic change occurs. If you leave the room, he may start to cry and try to look for you the last place he saw you – at the door. Or if he is playing with a toy, and you take it away and hide it behind your back, he will look for it behind you. These are signs that your baby has achieved an important intellectual milestone – object permanence. Baby's mind can now conjure up a visual image of a person or object, and "see" it in his mind even when it’s not physically there.

The process begins at four or five months, and is completed by the end of the second year. Recent research indicates that the process may, in fact, begin much earlier, but a baby simply has no way of displaying his grasp of the concept because of limited motor development.

During the period when object permanence develops, babies love to play games like "Peek-a-Boo, I See You." They demand to play again and again, and the joy that the experience brings is apparent. Why? Because in the real world, baby has no control over the people and things that disappear from him. His parents leave the room; and take a seemingly interesting toy away, perhaps because it is dangerous. In contrast, peek-a-boo-like games offer him some control. He can make his mother's smiling face appear and reappear over and over again from behind the door. He can press a button on his toy to make the clown jump up again and again. This newfound power and control is intoxicating and brings with it bursts of laughter and joy. This excitement peaks in the second half of the first year, when these types of game are the undisputed favorites.

After the age of 18 months, interest in these games diminishes, and the toddler simply puts to good use what he has learned and practiced. When his favorite toy goes missing, he will simply look for it in the last place he saw it, and if he doesn't find it, will continue looking in places where it is normally found.

Your role as parents

During the first six months, it’s important to introduce a routine and familiar layout in the child's environment to encourage her to become accustomed to having expectations. For example, she knows and learns to expect that there is always a mobile hanging from the crib, her favorite book is open on her play mat, and her bath is always given in the same manner. These things help baby to sense the concept of permanence in her life and begin to have expectations.

In the second half of the first year, play peek-a-boo-type games with your baby often, such as hiding and reappearing from behind a door, covering and uncovering your face with your hands, and hiding a toy and encouraging her to find it. There are a number of toys designed specifically for this, or that at least have elements in them that enable you to play with them for this purpose, such as pop-up games or a jack-in-the-box. These toys empower baby to play on her own, independent of the cooperation of others.