Jean Piaget's theory of cognitive development was based on the concept that children are not small adults. They have specific stages of development. The stages included the sensorimotor stage, which occurs around the ages of 0-2. During this stage children begin to experience spatial and sensory learning.
The next stage is the Preoperational stage. This stage generally occurs from the ages of 2-7. This stage includes the child’s abilities to begin classification. This lets the child combine like objects in basic groups based on things like size and color. Serialization also occurs during this stage and is the ability to organize things by progression, like size, numerical values or color shadings.
The third stage is known as the concrete operational stage, ages 7-11. In this stage the child begins to think in a more logical manner about objects and things going on around him. The child begins to achieve success in using the concepts of numbers, "understanding of quantity, length or numbers associated with an object or process."
The fourth and final stage Paget explains is the formal operational stage. This stage begins around the age of 11 and continues to adulthood. The abilities of the child continue to increase and expand. The child can think more logically and begins to comprehend hypothetical ideas, the concept of the future, and becomes less literal in his/her concepts of life.
"Piaget wrote that there are four major stages of cognitive development. These stages are invariant, hierarchical, and seen in children universally."