Visual and auditory development in an infant covers a number of important milestones. Even though the sense of hearing is quite developed at birth, infants need to learn how to interpret all of the things they are hearing. Vision is not fully developed at birth, so infants have even more milestones in that area. Parents should speak to their pediatrician if they have any concerns about their infant's development.
Visual, Birth to 7 Months
When infants are born, they can only focus on objects between 8 and 10 inches in front of them. It's not until an infant is 1 month that she can focus on an object moving from side to side. By 3 months old, infants can recognize people at a distance and follow objects moving in any direction. At around 4 months old, your infant's eyes will start working together so that she can track fast-moving objects and develop depth perception. As she matures, she'll become increasingly aware of colors and more complex patterns, as well. Instead of preferring the black and white geometric patterns she liked as a newborn, she will look for red or blue objects around her.
Visual, 8 to 12 Months
By the age of 12 months, infants have the same visual levels as adults. Their visual and motor coordination have matured so much, in fact, that they can even throw their baby food at you with a great deal of accuracy. Between 8 and 12 months, infants mostly just improve their eye-hand-foot-body coordination through crawling and playing, says the American Optometric Association. There are no specific milestones listed by the American Academy of Pediatrics.
Auditory, Birth to 7 Months
By the end of the first month, babies turn toward familiar sounds, such as their parents' voices, and react unhappily to loud noises. At 3 months old, they will smile at the sound of a parent's voice and may even start to babble. In the next few months, babbling strings of consonant sounds become much more common and your infant should start imitating sounds he has heard. At 4 months old, infants can distinguish emotions by the tone of voice and use their own voices to express joy and displeasure. They can also begin to recognize their own name and possibly even the word "no."
Auditory, 8 to 12 Months
For infants this age, auditory development is seen through language milestones. Their hearing is almost as developed as an adult's. They should be paying closer attention to speech and trying to imitate it through sounds and inflections. By 1 year old, they may even say a few words, attempt to imitate words and respond to simple verbal requests.