Jean Piaget’s ideas regarding how a child develops has had an enormous influence on our views about babies and children. He said children are not little adults; rather, their thinking is different.Covering every life stage from birth to death, Erik Erickson's theory differs from many other developmental theories and adds a social experience point of view to the discussion about development. He examined how a person socializes, and how this affects her sense of self and well-being.

Professional Similarities

Piaget (1896-1980) was a developmental psychologist and biologist. Erik Erickson (1902-1994) was a developmental psychologist and psychoanalyst. Both were developmental psychologists who brought another perspective and tradition to their work. The influence of their other professions can be seen in their theories. Piaget used ideas influenced by biology to explain children's development; for example, assimilation and accommodation are vital concepts in his theory. Both of these terms are related to adaptation to the environment and are used in biology. Erickson developed ego in this theory, a term that was introduced by Freud's psychoanalysis.

Stage Theories

Piaget described the cognitive development of children in his theory, which stresses internal growth and development. Erickson's theory describes how external social structure influences an individual. Both theorists proposed theories that are built upon stages.

Fixed Stages

Piaget's theory includes four stages of development; an individual reaches the final stages at around age 11. Erickson's theory contains eight stages, and an individual reaches the last stage at age 55 (or 65). Both theories stress that a person passes through fixed stages, and the order in which an individual passes through the stages is the same. It is not possible to jump over a stage and reach a higher stage more quickly.

Similar Stages

There are similarities in both theories in the ages at which children reach a stage and regarding the sequence of life events. Piaget's first stage takes place during a child' first two years, while Erickson’s first stage describes the first year. During the sensorimotor stage, Piaget says children learn to move and operate their bodies, and Erickson describes how a child learns to trust his environment and how this helps a child to grow as an individual. Piaget and Erickson stress the importance of reflexes and instinctive behavior during the first years. Both theories minimize the influences of biological changes during puberty and stress the importance of the development of self-concept during adolescence. Adolescence is Piaget’s final stage, called the formal stage. Erickson calls this stage adolescence.