PIAGET`S STAGES OF COGNITIVE DEVELOPMENT

Characteristics of the Preoperational Stage

The preoperational stage occurs between ages two and six. Language development is one of the hallmarks of this period. Piaget noted that children in this stage do not yet understand concrete logic, cannot mentally manipulate information, and are unable to take the point of view of other people, which he termed egocentrism.

During the preoperational stage, children also become increasingly adept at using symbols, as evidenced by the increase in playing and pretending. For example, a child is able to use an object to represent something else, such as pretending a broom is a horse. Role playing also becomes important during the preoperational stage. Children often play the roles of "mommy," "daddy," "doctor" and many others.

Egocentrism:

Piaget used a number of creative and clever techniques to study the mental abilities of children. One of the famous techniques egocentrism involved using a three-dimensional display of a mountain scene. Children are asked to choose a picture that showed the scene they had observed. Most children are able to do this with little difficulty. Next, children are asked to select a picture showing what someone else would have observed when looking at the mountain from a different viewpoint.

Invariably, children almost always choose the scene showing their own view of the mountain scene. According to Piaget, children experience this difficulty because they are unable to take on another person's perspective.

Conservation:

Another well-known experiment involves demonstrating a child's understanding ofconservation. In one conservation experiment, equal amounts of liquid are poured into two identical containers. The liquid in one container is then poured into a different shaped cup, such as a tall and thin cup, or a short and wide cup. Children are then asked which cup holds the most liquid. Despite seeing that the liquid amounts were equal, children almost always choose the cup that appears fuller.

Piaget conducted a number of similar experiments on conservation of number, length, mass, weight, volume, and quantity. Piaget found that few children showed any understanding of conservation prior to the age of five.