The stages of child development are typically divided into the following categories: Infants or babies, toddlers or preschoolers, school age, and adolescent or teenager. Furthermore, Piaget's cognitive stages of development include sensorimotor, preoperational, concrete operational and formal operational.
The first two years of a child's life are often called the infant or baby stage, during which developing initial human bonds is imperative. During the preschool or toddler stage, which lasts from around age 2 to 5, children interact with the world around them and begin to develop independence. School age, spanning ages 6 to 12, is an important time to develop social skills and to lay a foundation for future beliefs and behaviors. The adolescent or teenager stage lasts from about age 13 to 18 and is a time of maturing and seeking more independence.
When tracking intellectual development, Piaget's stages of development are often referenced. The sensorimotor stage lasts from birth to approximately 24 months and is marked by increasing physical interaction with immediate objects. The preoperational stage, which lasts until around age 7, is when memory and imagination develop and children become capable of thinking of things symbolically. The concrete operational stage, from age 7 to 11, is when logic and reasoning develop. The formal operational stage begins at age 11 and is when children can understand abstract concepts.