Outward evidence of a baby's learning and thinking is subtle at first: the newborn modifying his sucking to adapt to the breast, bottle, or pacifier; the 3-week-old who takes a break from feeding to look into her mother's eyes. Because a newborn's vision is believed to be no better than 20/400 -- meaning he sees things at 20 feet away as a person with perfect vision would see them from 400 feet away -- he can focus only on things within seven to ten inches from his face. So he is more attracted to stark contrasts, such as black and white. But as the connections between neurons in the brain's visual cortex increase, a baby begins to see more clearly. His depth perception also develops as he begins to coordinate his eye movements so that both eyes focus on the same thing at the same time. Now a baby may become fascinated by the finer features of a toy or his parents' faces, noticing three-dimensional details rather than looking only at the edges of objects.
By the time babies are 2 to 3 months old, they'll begin watching people as they walk across the room and be able to make eye contact with Mom and Dad. At this point, vision improves enough that babies are ready for new things to stimulate them (while still being attracted to the details of familiar objects that they are only now noticing). Vision improves to 20/60 or better around 6 months of age, allowing your little bundle to distinguish your face from the sea of adult faces he's already encountered.
Nelson believes that this ability to recognize caretakers also sparks a primitive understanding of cause and effect: "When I'm hungry, one of them feeds me," thinks the baby. An infant may look across the room toward the refrigerator because she's learned that bottles come from there. A breastfed baby may look at Mom the same way, as if to say, "Hey, there's the one with the milk!"
By 4 to 5 months of age, a baby will visually follow an object -- such as a spoon or a rattle -- when it falls out of her hand, marking the beginning of her understanding that she is separate from other people and things around her. Simple hiding games and rounds of peekaboo help a baby learn that objects and people still exist when she can't see them, and this leads to her ability to draw mental pictures of things that are not right in front of her. This could be the first step toward an active imagination.
Cracking the Code
As your baby's brain develops, you'll be delighted by those surprising moments when your tot lets you in on how much he's learned so far. Ami Day of St. Louis, MO, got a taste of this when her daughter, Mackenzie Ekren, started babbling out conversations at 6 months of age. "Her tone varied," said Day. "It wasn't a monotone like I thought it would be." Mackenzie showed that she understood the give-and-take of conversations by ending her stream of sounds to wait for a response. If there was none, she arched her eyebrows expectantly, waiting for her mother's reply. Her mother held up her end of the conversation either by saying something or by imitating her daughter's babbling, which gave Mackenzie enough reinforcement to mimic her mother right back and to try to outtalk her.
Interactions like this mark huge strides in cognitive development. "A baby is beginning to crack into the huge world of encoded communication that flies around -- what we call language," says Leslie. As the baby's babbling becomes more distinct (around 8 to 10 months), parents begin to wonder if she is actually forming words: "mama," "dada," or even complex phrases. But in general, babies this age don't associate words with meanings. Even if they say, "mama," they don't yet know that's your name. Around 10 to 12 months of age, they will start to acknowledge that words have meanings, but they may use one word for several purposes. For instance, a 1-year-old may use "cookie" to say, "I want a cookie," "I'm hungry," "That's a cookie," or a plethora of other things she associates with that particular word.
By babbling, a baby practices forming the varied sounds of her native language, with parents trying to help by providing lots of verbal input. When Margie Gitten, of Weston, FL, pointed to the polka dots on the nursery wall, she named each color for her daughter Emily. Emily cocked her head and looked as if she was registering the information. Although the 7-month-old wasn't yet able to learn colors, the interaction with her mom eventually helped her understand how groups of sounds form words, and how words represent things in her world.