From the very beginning of life, children demonstrate curiosity and an ability to learn. They explore the objects around them, interact with others, and engage in play activities, all of which help them gain an understanding of themselves and of their world. Cognitive development encompasses thinking, learning, reasoning, and memory, and as children improve these skills, they will grasp the function of everyday objects and start to understand more complex concepts, like counting and time. Cognitive abilities will be crucial to them as they enter school, and with these skills in place, they will be able to expand upon the knowledge they have already developed. A delay in these milestones may indicate certain health conditions, including mental retardation, Down syndrome, learning disabilities, and autism spectrum disorders.

The milestones included below are meant to illustrate the general path of cognitive development, but they should not be viewed as a fixed timeline. All children are unique in their development, and one missed milestone is not necessarily a cause for concern. A child who is very behind in one area of development or has missed milestones in several areas of development should see a pediatrician, and parents should talk to their child’s doctor whenever they have questions or concerns.

Cognitive Milestones:
3 months - The child looks at his hands, plays with his fingers, can bring his hands to his mouth.
7 months - The child can find objects that have been partially hidden, explores objects with hands and mouth, will try to reach objects that are far away.
1 year - The child uses different methods for exploring objects (shaking, dropping, banging), can easily discover objects that have been hidden, looks at the correct picture of an object that has been named, imitates the gestures of others, begins to use objects in the correct manner (drinking from a cup or brushing hair with a hairbrush).
2 years - The child can find objects that have been hidden under two or three objects, engages in make-believe play.
3 years - The child can use mechanical toys, can match objects with pictures in a book, can sort objects by shape and color, completes puzzles that have three or four pieces, comprehends the concept of “two,” uses dolls during make-believe play.
4 years - The child can correctly identify some colors, understands the concept of counting and might know some numbers, begins to understand the concept of time, can complete three-part commands, can remember parts of a story, understands “same” and “different,” tries to solve problems.
5 years - The child can count to ten or higher, can name at least four colors, has a better understanding of time, knows the function of everyday objects.

Possible Signs of Cognitive Delays:
3 months - The child has not noticed his hands.
7 months - The child shows no interest in playing peek-a-boo by 8 months.
1 year - The child does not search for objects that were hidden while he watched.
3 years - The child does not engage in pretend play.
5 years - The child cannot understand two-part commands involving prepositions (“put the book on the table and get the ball from under the chair”).