Erik Erikson is a 20th-century psychoanalyst best known for his psychosocial theory of development that considers the impact of socialization on personality development from childhood to adulthood. This theory has eight distinct stages, each the potential root of later health and pathology. Since Erikson believed that personality and identity were shaped over the lifespan, he maintained that experiences later in life could heal problems from early childhood.

Infant: Trust vs. Mistrust

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As infants, children learn to trust others based upon the consistency of their caregivers. If children receive adequate and nurturing care at this stage, they will develop optimism, trust, confidence and security. Unsuccessful completion of this stage can result in an inability to trust, which may cause anxiety, heightened insecurities and a general mistrust of the world.

Toddler: Autonomy vs. Shame and Doubt

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Between the ages of 1 and 3, children begin to exert their independence. If children in this stage are encouraged and supported in their increased independence, they become more confident and secure in their own ability to survive in the world. If caregivers discourage children's independence during this stage, through harsh criticism or excessive control, children begin to doubt their own abilities to survive in the world, becoming overly dependent on others and lacking in self-esteem.

Preschooler: Initiative vs. Guilt

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As preschoolers, children become curious about people and imitate the adults around them. They begin to plan activities, make up games and initiate activities with others. If given this opportunity, children develop a sense of initiative and feel secure in their ability to lead others and make decisions. If children are not able to take the initiative and succeed at appropriate tasks, they may develop a sense of guilt, which can lead to inhibition.

School-Age Child: Industry vs. Inferiority

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At this stage, children begin to develop a sense of pride in their accomplishments. They initiate projects, see them through to completion and feel good about what they've achieved. During this time, teachers play an important role. If children are encouraged and positively reinforced for their initiative, they begin to feel industrious and confident in their ability to achieve goals. If children are restricted from accomplishing their goals by their caregivers or teachers, they begin to feel inferior, doubting their own abilities.

Adolescent: Identity vs. Role Confusion

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At this stage, children become adolescents struggling to discover their own identity. They start to care about how they look to others and begin to experiment to find out who they are. If adolescents are encouraged to explore their possibilities and thus start to form their own identities, they develop a strong sense of themselves. Those unsuccessful during this stage tend to experience role confusion and internal upheaval.

Young Adult: Intimacy vs. Isolation

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At the young adult stage, people tend to seek companionship and love. Intimacy is based in part upon identity development, thus individuals in this stage must know themselves to be able to share intimacy. Failure to develop intimacy can lead to promiscuity, or getting too close too quickly and not sustaining it. Or it can lead to exclusion or rejection of relationships and those who have them.

Middle-Aged Adult: Generativity vs. Stagnation

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During middle adulthood, people establish their careers, settle down within a relationship, raise families and develop a sense of being part of a bigger picture. People are working to establish stability and attempting to produce something that makes a difference in society. Inactivity and meaninglessness are common fears during this stage. Adults can develop a sense of stagnation, become self-absorbed and offer little to society. Too much stagnation can lead to the unresolved midlife crisis.

Older Adult: Ego Integrity vs. Despair

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Erikson believed that much of life is preparation for the middle adulthood stage, while the last stage involves reflection. People contemplate their accomplishments during this stage and develop ego integrity if they see themselves as having led a successful life. If they see themselves as unproductive, feel guilt about their pasts or feel that they didn't accomplish their life goals, they become dissatisfied with life and develop despair, which can lead to depression and hopelessness.