Piaget's cognitive theory of development encompasses four main stages: the sensorimotor from 0-2 years, the preoperational from 2-7 years, the concrete operational from 7-11 years, and the formal operational from 11 on. Piaget believed that older children not only know quantitatively more than younger ones, but actually think in qualitatively different ways. His theory focusses on how children think and represent the world, and how these capabilities change as the child matures (Jackson, Robinson & Dale, 1977). In this paper I will examine in detail the preoperational stage of development, including its characteristic abilities (such as language and socialization of behavior) and its limitations (such as egocentrism and failure to conserve, among other things).
In the preoperational period, sensorimotor functioning decreases and the use of conceptual representation increases. "The child becomes increasingly able to internally represent events (think) and becomes less dependent on current sensorimotor actions for direction of behavior." (Wadsworth, 1979, p.69). The acquisition of language is, therefore, one of the most dramatic and far-reaching developments of this stage. Children typically begin using spoken words as symbols in one-word sentences around age 2; by age four they can speak and comprehend language remarkably well (Santrock, 1983).
This new capability is instrumental in facilitating other intellectual development as well. The use of language has three important consequences for cognitive development in general. First, the possibility of a verbal exchange with others marks the beginning of true socialization of action. Second, the internalization of words, which originally occurs through imitation, allows for the appearance of what we, as adults, recognize as thought. Third, the mental representation of actions, objects, and events, which were formerly available on a purely perceptual or motor level, means th...