Piaget’s Contributions

Piaget’s theory involves a discontinuous process of development in four major
stages. The sensorimotor stage (birth to two years) is followed by the
preoperational stage (two to seven years), the concrete operational stage
(seven years to adolescence), and the formal operational stage (adolescence
to adulthood). During the sensorimotor stage, the child’s behavior is
largely reflexive, lacking coherent conscious thought; the child learns that
self and world are actually different, and that objects exist even when they
are not visible. During the preoperational stage, the child learns to infer the
perspectives of other people, learns language, and discovers various concepts
for dealing with the physical world. In the concrete operational stage,
the ability to reason increases, but children still cannot deal with abstract issues.
Finally, in formal operations, abstract reasoning abilities develop. The
differences between the stages are qualitative differences, reflecting significant,
discrete kinds of behavioral change.

Piaget’s theory is not entirely accurate; it does not apply cross-culturally
in many instances, and children may, under some experimental circumstances,
function at a higher cognitive level than would be predicted by the
theory. In addition, some aspects of development have been shown to be
more continuous in their nature than Piaget’s ideas would indicate. Yet
Piaget’s formulation is relatively parsimonious. The various aspects of the
theory are readily testable and falsifiable, and the heuristic utility of these
ideas has been enormous. This theory has probably been the most successful
of the several extant perspectives, and it has contributed significantly to
more recent advances in developmental theory. This progress includes the
work of James J. Gibson, which emphasizes the active role of the organism,
embedded in its environment, in the development of perceptual processes;
the information processing theories, which emphasize cognitive change;
and the ethological or evolutionary model, which emphasizes the interplay
of developmental processes, changing ecologies, and the course of organic
evolution.