Each of the stages is age-related and consists of distinct ways of thinking. The sensorimotor stage, which lasts from birth to about two years of age, is the first Piagetian stage. At the beginning of this stage, newborns have little more than reflexive patterns with which to work. The preoperational stage, which lasts from approximately two to seven years of age, is the second Piagetian stage. In this stage, children begin to represent the world with words, images, and drawings.
Symbolic thought goes beyond simple connections of sensory information and physical action.
However, although preschool children can symbolically represent the world, according to Piaget, they still lack the ability to perform operations, the Piagetian term for internalized mental actions that allow children to do mentally what they previously did physically. The concrete operational stage, which lasts from approximately seven to eleven years of age, is the third Piagetian stage. In this stage, children can perform operations, and logical reasoning replaces intuitive thought as long as reasoning can be applied to specific or concrete examples. For instance, concrete operational thinkers cannot imagine the steps necessary to complete algebraic equation, which is too abstract for thinking at this stage of development. The formal operational stage, which appears between the ages of eleven and fifteen, is the fourth and final Piagetian stage.