If you watch babies, you’ll notice they pay a lot of attention to what’s around them. An infant's eyes might be glued to you as you fix her a bowl of rice cereal. She might try to follow the family cat around to touch it. Because they can’t talk yet, babies pose a real challenge for researchers who want to figure out what’s going on in infants' brains. However, by tracking eye movement and actions, scientists have been able to draw conclusions about babies’ thinking. With this knowledge, parents can interact with their infants in ways that encourage their cognitive development.
Out of sight, out of mind -- that seems to be true for young infants. It takes a while for them to develop the idea that things still exist even though they can't be seen. Although some psychologists disagree about how early this "object permanence" develops, 4- and 5-month old babies show some understanding of the concept. At this age, babies watch the movement of a ball when it rolls behind an obstacle. Once the ball is hidden, the infants' eyes continue to move to the spot where they predict the ball will show up again. This action indicates babies are aware the ball has not disappeared for good.
Young babies love peek-a-boo. They will laugh when you suddenly appear from behind your hands because they are so delighted and surprised you showed up again. However, slightly older infants have indicated they form pictures or mental representations of objects that are hidden. By 10 months they will search for a toy that has been covered by a cloth. They can also make mental representations of concepts and group similar things together. For example, researchers found that at 6 months, babies can copy adult actions to make a puppet ring a bell. Later, the babies will generalize this to different puppets and repeat the same motions to try to get the new puppet to make the same noise.
At 7 to 8 months, babies can purposely perform actions to get what they want. For example, if an attractive toy is resting on a cloth but is out of reach, an infant will pull on the cloth until the toy is close enough to grasp. Slightly older babies can use a series of steps to gain a toy. They can get around a barrier, and grab a string and pull on it to get hold of a plaything. Infants 10 to 12 months can generalize this activity and repeat the process even if the barrier, string and toy are different from the original set-up.
Infants are intentionally communicating their wants and needs from an early age. Within the first few months a baby can purposely cry to inform his caregivers of a problem, such as hunger, a wet diaper or too much light. By 5 months, infants are regularly making noises with vowels because they haven’t developed enough mouth and tongue control to produce other sounds. Within the next two months babies add consonants to their repertoire. Between 7 and 12 months babies combine many sounds that resemble language. Sometimes it’s pure coincidence, but by the end of 1 year it’s not surprising to hear a baby use the real word to indicate a familiar object, such as “mama,” “dog” or “ball.”