Jean Piaget effectively started the "cognitive revolution," assessing his own children and the answers children supplied in tests. He found clues in children's wrong answers which led him to a clinical method of observation and flexible questioning. Children have, he perceived, an inborn ability to adapt to their surroundings.
As a result of his research, his theory of cognitive development has four different stages which can be applied universally. In the first stage - The Sensorimotor stage - infants (up to 2 years old), who begin life with basically random behavior, become goal-oriented. From chance associations, babies learn to reproduce enjoyable results.
Between the ages of 2 and 7 years, although logical thinking is not yet developed, children begin to use recall rather than physical representations and their system of symbols develops; for example, a child who wants ice-cream now remembers the taste and does not need a physical prompt. This is the Preoperational stage. The sensory cue is sufficient. This also means that language and imagination develop rapidly in this stage. Toys become representative of reality - playing house, making pretend tea, having a picnic with teddy bears and dolls, and so on.
Logical connections follow and between about 7 years of age and 11 children solve problems concerning actual events or difficulties. This is the stage of Concrete Operations. Provided that they represent tangible things, they can solve problems like, for example, finding their own way to school (within reason) and understanding distances between places.
Once entrenched, children can begin thniking abstractly and from about 11 years of age through adulthood the Formal Operations stage is apparent. Options and possibilities become part of the thinking process and hypothetical situations and abstract concepts become part of reasoning.
3. Concrete operations