Two well-respected social scientists who theorized on human development are Erik Erikson and Jean Piaget. Erik Erikson’s theory of human development addresses the tasks of various age groups and the potential negative effects of unsuccessfully attempting those tasks. Jean Piaget focused on cognitive development from birth through the adolescent years.

Erik Erikson’s theory of human development addresses the tasks of various age groups. According to a report from Honolulu Community College, the developmental goal of infancy is for the child to develop either a sense of trust or a sense of mistrust. The level of comfort the baby receives during this stage of life correlates to her attainment of trust.

Jean Piaget’s theory of cognitive development focuses on the infant’s progress to intellectually make sense of her world. During the sensory-motor stage, according to the Child Development Institute, the infant progresses from possessing the reflexive skills of grasping and sucking to more advanced infant skills, such as hitting an object on a mobile with the realization that the mobile moves when she hits it.

Early Childhood

Erikson’s theory for toddler development describes the task of gaining a sense of autonomy versus gaining a sense of shame or guilt. Toddlers who succeed in doing for themselves attain this goal while toddlers who are more dependent struggle. In the preschool stage, young children begin to initiate tasks on their own. If unsuccessful in this stage, the result is the child developing a sense of doubt.

Piaget’s theory for cognitive development for early childhood spans from age 2 to age 7 and is known as the preoperational stage. During this time period, the toddler increases the use of words to communicate his own needs. In later years of this stage, the child becomes more social with others. He also is limited in his understanding of complex processes; thus, focusing on one aspect of a concept at a time makes it easier for him to understand.

School Age

Erikson identifies the task of industry for the school age child. This outlines the goal of the child to either learn to do more complex tasks by herself or, if unsuccessful, to gain a sense of inferiority.

Piaget’s theory of children ages 7 to 12 is the period of concrete operations. In this stage, the child learns complex concepts. An example of a complex concept typically learned at this stage is that of conservation, an example of which is understanding that a tall narrow glass holds the same amount of liquid as a short, fat glass.


Gaining an identity is the task of adolescence, according to Erikson’s theory. Failure to explore the varying roles one person can have can lead to what Erikson calls confusion; The varying roles a teenager takes on helps build her sense of self.

Piaget’s period of formal operations is his final stage of development. This time frame, from age 12 and up, allows the individual to understand and perform complex tasks and build upon those tasks. The ability to understand abstractions is another accomplishment accorded to this stage of cognitive development.


Erikson’s theory of development continues beyond the childhood and adolescent years and addresses the tasks of three stages of adulthood. During the young adult period the task is, according to Erikson, to commit themselves to others in the form of intimacy. The lack of success in this task leads to isolation. In the middle adult years, the individual seeks to be productive to themselves, their families and their communities. The task, therefore, is to gain a sense of generativity, which is preferable to the opposite task, which is to gain a sense of stagnation. Finally, the successful older adult seeks to gain a sense of integrity at the expense of a sense of despair. This stage includes reflection on his life and the experience of loss.