The newborn days are behind you. As your baby becomes more alert and mobile, each day will bring exciting new adventures. Every experience, from cuddling before nap time to listening to a sibling's chatter, will help your baby learn more about the world.

Expect your baby to grow and develop at your baby's own pace. But consider these general infant development milestones as your baby's personality appears.

Most babies will become more aware of the world around them and want to explore. From ages 4 to 6 months, your baby is likely to enjoy:

• Evolving motor skills. Your baby's arms and legs probably wiggle and kick more purposefully now. Your baby is likely rolling over. Your baby's head control will get better as the muscles gain strength. Most babies this age raise their heads when lying facedown. They might even try to push themselves up or bear weight on their legs. Around age 6 months, many babies begin sitting alone after being positioned upright.
• Improving hand-eye coordination. Your baby will probably grasp your finger, a rattle or a soft object. Anything within reach is likely to end up in your baby's mouth. You might notice your baby pulling objects closer with a raking motion of the hands.
• Clearer vision. Your baby is starting to be able to tell the difference between shades of reds, blues and yellows. Complex patterns and shapes become more interesting at this age. You might notice your baby focusing on a toy or staring at their reflection. If you roll a ball across the floor, your baby will probably turn the head to follow the action.
• Babbling and other new sounds. Babies this age often start to babble chains of letter sounds, such as "ba" or "dee." Your baby might react to sound by making sounds and use the voice to express joy. Your baby also might be able to tell between emotions by tone of voice, and begin replying to "no." Some babies might even know their name.

At this age, learning and play go together. But it doesn't take expensive educational toys or intense effort to capture your baby's attention. To promote infant development:

• Talk to your baby. Ask questions and react to your baby's coos and gurgles. Describe what you see, hear and smell around the house, outdoors, and when you're out and about. Use simple words such as "baby," "cat," "go," "walk," "hot" and "cold." Remember that your tone of voice and facial expression can communicate ideas and emotions.
• Turn on the tunes. Music can help calm, entertain and teach your baby. Sing or play lullabies, upbeat children's songs or your own favorites.
• Change positions. Lay your baby on the tummy for a few supervised minutes. Many babies enjoy practicing their new rolling skills, and they may roll over quickly. Hold a colorful toy or make a noise to encourage your baby to pick up the head or practice rolling over. Hold your baby's hands while lying down and say, "Are you ready to stand up? Here we go!" Count to three as you gently pull your baby to a standing position. When your baby's ready, try a sitting position. Hold your baby or use pillows for support.
• Offer simple toys. Babies this age often enjoy colorful toys, especially those that make sounds. Try a musical toy, a mirror, a rattle with a handle. To help your baby focus, put out only one or two toys at a time. Place one toy slightly out of reach to encourage your baby to stretch and creep. Shake a rattle behind your baby's head so that your baby can turn and grab it. Babies may also like to watch their movements in a mirror.
• Read to your baby. Reading to a baby helps with speech and thought development. Most babies will soak in your words and might even mimic the sounds you make. Start with books that have large, brightly colored pictures. Describe what's happening on each page. Point to and name common objects. You might make this part of your routine before putting your baby to bed.
• Play favorite games. Cover your face with your hands, then remove your hands and say, "Peekaboo, I see you!" Play patty-cake. Ask, "Where are your toes?" Then touch your child's toes and say, "Here are your toes!" Hide one of your baby's toys with the corner of a blanket and encourage your baby to find it.
• Take time to cuddle. Balance new events with plenty of quiet time. Gentle caresses and tender kisses can help your baby feel safe, secure and loved. When you hold or rock your baby, talk quietly or sing soothing songs.
• Get to know your baby's personality. Start to notice how your baby reacts to new toys, people or situations. Figuring out your baby's behavioral style, called temperament, will help you both be less stressed.

Your baby might reach some developmental milestones ahead of schedule and lag behind a bit on others. This is common. But it's a good idea to be aware of the signs or symptoms of a problem.

Consult your baby's health care provider if you're concerned about your baby's development or your baby:

• Has very stiff or tight muscles.
• Seems very floppy.
• Reaches with only one hand.
• Hasn't shown any improvement in head control.
• Doesn't respond to sounds, such as by startling to sudden loud noises.
• Doesn't reach for or bring objects to the mouth.
• Doesn't attempt to roll over.
• Has an eye or eyes that consistently turn in or out.
• Doesn't babble.
• Doesn't seem to enjoy being around people or spontaneously smile.

Trust your instincts. The earlier a problem is found, the earlier it can be treated. Above all, delight in your baby's discoveries and abilities.