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' sensory and 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.
- Between 9 months and 12 months of age, babies explore the world with all their senses. At the same time, they are developing more control over their hands and fingers and may be able to grab small objects with a forefinger and thumb. Most babies this age like to experience and explore objects through taste and texture, which prompts them to put almost anything they can into their mouths. 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.