Social and Cognitive Developmental Milestones: From Birth to 2 Years

Children grow quickly, but the rate of growth is less important than the way they learn new skills. The following developmental guidelines can give you an idea of when babies generally make certain advances in two of the four developmental categories: social and cognitive. It's important to remember, though, that your child is an individual, and progress may vary slightly.

Social development

Social development refers to your child's emotional needs and ways of responding to and interacting with others, for instance, your baby's reaction to being separated from you or encountering a new situation.

  • Birth to 3 months old. Your infant may smile in response to your voice and focus on your face when you talk. Babies in this age group may also begin to develop their own easygoing, sociable or serious personality.
  • 3 to 6 months old. By this stage, your baby can distinguish emotions in your voice and facial expressions and may respond to them. Babies continue to communicate using sounds, gestures, facial expressions and crying. At this age, babies who are curious about voices or noises will turn their head in response.
  • 6 to 9 months old. During this phase, babies may smile at people they recognize and show fear of strangers. Your child will probably use his or her hands to explore your face and hands and begin to show interest in other children. Babies at this stage of development enjoy playing interactive games like waving bye-bye, patty-cake and peek-a-boo with you and may respond to their reflection in a mirror.
  • 9 to 12 months old. Expect a messy mealtime, as children at this age may now want to feed themselves. Your child may also begin to wave bye-bye when leaving or when seeing others leave.
  • 12 to 18 months old. By now, your child is aware of your daily routine and can show emotion and affection to you, other family members, pets and toys. Your toddler is beginning to enjoy group play more, as long as you are close by, but hasn't quite mastered playing with another child and instead plays near another child.
  • 18 to 24 months old. You may notice that your toddler seems to be curious about everything, including other children. Your child may watch and imitate you or others and begin to identify people by name. Though you're bound to see an increase in tantrums at this age, you may also find that you have a new little helper, since your child now enjoys helping you more than ever before.

Cognitive, or intellectual, development

Cognitive development is the process by which babies learn problem-solving skills and come to relate to the world around them, for example, what your baby thinks when you hide beneath a blanket. At a very young age, your baby will think that you are gone, but older babies will understand the person is hidden but still present.

  • 3 to 6 months old. Your little one is perfectly happy just looking around and may begin to recognize patterns, familiar objects and even you! Babies in this age group may soon find their feet and enjoy playing with them. They will also begin to anticipate their daily routine and associate actions with certain results, for example, batting a certain toy will make it spin or squeak.
  • 6 to 9 months old. Now your baby can understand how simple toys, like balls, cars and squeak toys, work. Babies at this age may also recognize familiar routines, like bath and bedtime.
  • 9 to 12 months old. By now, your baby can understand simple sentences and questions. Even though it may be hard to tell, children can now remember their parents even when they can't see them. At this age, babies will also experiment with putting objects in spaces, taking them out and throwing them down.
  • 12 to 18 months old. Your toddler may learn best by experimenting now. During this period, babies are increasingly able to find and recognize objects, including their cup, clothing or toys, on their own or when you ask for them.
  • 18 to 24 months old. Now children can begin to remember what comes next in their daily schedule. You may notice that children are more possessive at this age, using words like "mine," "I like" or "I don't want," and they may be able to identify their belongings among others.

You can learn more about the milestones in your baby's life by visiting the Ages and Stages section of the website for the American Academy of Pediatrics. If you ever have concerns about your child's growth and development, be sure to address them with your pediatrician.

For more information about the stages of growth in your child, visit the Infant, Toddler, Pre-school section of the Children, Youth and Teens page of Military OneSource.



Find programs and services at your local installation.

View a directory of installations

Service members, family members, surviving family members, service providers and leaders rely on Military OneSource for policy, procedures, timely articles, cutting-edge social media tools and support. All in one place, empowering our military community.