Sensory and motor development is the gradual process by which a child gains use and coordination of the large muscles of the legs, trunk, and arms, and the smaller muscles of the hands. A baby begins to experience new awareness through sight, touch, taste, smell, and hearing.
Babies’ motor development generally follows a typical pattern:
- At 1 month of age, babies’ neck muscles are not developed enough to support their heads for prolonged periods of time. Babies can lift their heads only briefly when lying on their stomachs. Limb movements are influenced by newborn reflexes, such as the startle reflex, which makes a baby throw out his or her arms and spread the fingers in response to a loud noise or other sudden, unexpected stimulus. By 6 weeks of age, newborn reflexes begin to fade and the baby’s strength and coordination improve.
- By age 3 months, your baby can control his or her head movements. Put your baby on his or her tummy during awake periods and closely supervise. Allowing your baby to exercise and move in this position helps develop head and neck muscles. Around 4 months of age, babies gain control and balance in their head, neck, and trunk. Most babies can balance their heads for short periods when in a stable position. Around this same age, your baby starts playing with his or her hands and grasps your finger on purpose, rather than as a reflex.
- Between 4 and 6 months of age, babies’ balance and movement dramatically improve as they gain use and coordination of large muscles. During this time, babies purposefully roll over and may be able to sit with their hands balancing them in front (tripod position). Reaching toward an object with both hands, babies may grasp at toys with their palms.
- Babies gain more control of their muscles between 6 and 9 months of age as the nervous system connections continue to form. By the 7th month, babies can see almost as well as an adult. Babies develop leg and trunk coordination, sit alone steadily, and may crawl using both their hands and feet. Some babies even pull themselves up to a standing position, although the timing and sequence of these milestones vary widely.
- Around 9 to 12 months of age, babies develop more control over their hands and fingers and may be able to grab small objects with a forefinger and thumb. The brain continues to grow, helping to refine control over the large muscles. By now, your baby will probably be able to crawl and stand. In these few months before babies begin to walk, they often spend hours “cruising” around the room holding on to furniture and other objects. Cruising develops muscles and coordination and gives your baby a chance to practice walking.
- Many toddlers start to walk around 9 to 15 months of age. Those first steps are possible because of changes that have taken place in the brain and the spinal cord.
Babies’ sensory development generally follows a typical pattern:
- Vision. At 1 month of age, babies can see about 30 cm (12 in.) in front of them. Babies this age especially enjoy looking at the human face and bright contrasting colours. At 2 months of age, babies begin to be able to follow a toy or other object when it is moved in front of their face. At 3 to 4 months, babies can focus on an object or your smiling face from 1 m (1.1 yd) to 2 m (2.2 yd) away and begin to see a full range of colours. At 7 to 12 months, a baby’s vision is the same as an adult’s vision.
- Hearing. At 1 month of age, babies strongly prefer the sound of the human voice. Hearing is the same as an adult’s hearing. They recognize the voice of their caregiver, even when they are in another room. At 2 months of age, babies begin to coo and make sounds, such as ooh and ahh. At 4 months, babies often amuse themselves with babbling and are beginning to understand that tone of voice means different things. At 6 or 7 months, babies start copying the sounds they hear spoken. Babies may not be able to say the words they are hearing yet, but they can understand many of the words you say. At 12 months, babies are working hard to master language, and soon they may say their first word.
- Touch. Babies of all ages have a well-developed sense of touch. They often prefer soft, gentle touches and cuddles.
- Smell and taste. Babies of all ages have a well-developed sense of smell and taste. They prefer sweet smells and know the smell of their mother’s breast milk. At 9 to 12 months of age, most babies like to experience and explore objects through taste and texture, which prompts them to put almost anything they can into their mouths.