Chapter 8: Lifespan Development of Human Potential
Chapter 8: Lifespan Development of Human Potential
Theories of Development
Piaget’s Stage Theory of Cognitive Development[
In Chapter 7, we saw how the ability of chimpanzees to solve two-choice visual discrimination problems improved gradually over the course of 300 problems. At the end, the chimp appeared to solve the problems in a qualitatively different manner. Rather than observing gradual improvement across the first six trials of each new problem, the chimp would jump from chance to perfect performance on the second trial (Harlow, 1949). One might conclude, it transitioned from an “incremental” stage to a “hypothesis-testing” stage of development. The name of the stage is descriptive of the performance, not explanatory. The explanation lies in the history of exposure to examples of the same type of problem. Although heredity and environment interact gradually and incrementally, sometimes the behavioral effect appears to constitute a qualitative change in the individual. The ability to comprehend language and speak result from physical development of the infant’s brain and speech organs, improved ability to imitate, and continual exposure to vocalizations.
Jean Piaget, a Swiss psychologist, proposed an influential theory of cognitive development from birth through adulthood (Piaget, 1928; 1952; 1962; Piaget & Inhelder, 1973). Piaget was an example of a stage theorist. Stage theory describes human development as a fixed sequence of capabilities resulting in qualitatively different ways of responding to the world. Piaget describes cognitive development as the continual modification (i.e., accommodation ) of schemas based on the incorporation (i.e., assimilation ) of new knowledge. Piaget applied the overarching principles of assimilation, accommodation, and schema development to integrate the cumulative interactive effects of heredity and experience as the child ages and advances through the different stages.
The sensorimotor and pre-operational stages last from infancy through preschool and the early grades. During the sensorimotor stage (from approximately birth to two years) the child is preverbal, learning the relationships between sensory (e.g., visual and auditory) stimuli and movement. During the pre-operational stage , the child is able to use language to acquire skills and knowledge. Interacting with a child that speaks is fundamentally different than interacting with a non-verbal child. Piaget’s distinction between non-verbal (sensorimotor) and verbal (pre-operational) stages seems appropriate and important. A child is able to learn in a qualitatively different way once acquiring speech. We need to be careful, however, in how we interpret the meaning of a stage of development. It is one thing to describe the child as behaving as though being in a particular stage and a very different thing to offer the stage as an explanation for behavior. You might recognize this as another example of a pseudo-explanation. Why does the child speak?