1985, p. 18).
From the beginning of his life outside of the womb, the infant himself takes a controlling hand in obtaining and then organizing all his experience of the outside world. This process of absorbing and organizing experiences around the activities that produce them Piaget calls assimilation (Isaacs, 1985).
To further describe the stages of development, Piaget constructed four schemes, or miniature models of the world that the child builds from it. These four schemes are: 1) sensimotor period from birth to 2 years; 2) preoccupational period from 2 to 7 years; 3) period of concrete operations from 7 to 11 years; and, 4) period of formal operations from age 11 through adulthood (Bee, 1999). In each stage of development, specific processes occur, serving to a degree as building blocks upon which further development and maturation can be based. Each scheme can combine with another scheme to form larger units that in turn form increasingly complex and sophisticated models of the world that would emerge in later life and define the most advanced forms of human thought. What is useful and important about these "stage theories" is that they provide a basic framework for the investigation and analysis of human cognitive development within which individual variations can be better understood (Gerow, Brothern, and Newell, 1990).
In nativism, it is held that from about one to thee years of age, the developmental evolution of the child shifts from the oral to the anal stage. Formerly, the oral zone (i.e., the mouth) was the focus through which the child "saw" or experienced the world; impressions and sensations, both painful and pleasurable, were concentrated in this physiological region of the body (Miles, 1997). With the shift to the anal zone, and the corresponding introduction of the anal stage, the focus of both experience and sensation shifts. Until the age of one, and up to the age of three, most infants e...