Psychology has many theories of personality development with the Erikson model proving to be most popular. Eric Erikson proposed eight stages through which a healthy developing human should pass from infancy to late adulthood. With each stage, a person meets and completes new challenges. The psychoanalyst theorized that personal development was directly impacted by social experiences.

The last stage of life, or Integrity vs. Despair, involves reflection on a life lived. This stage encompasses ages 65 and up as a time to contemplate accomplishments and failures, aging, the end of life, and loss. Those who feel proud of their accomplishments feel a sense of integrity. They have few regrets and feel they will leave a legacy of contributing to the world. If a person thinks there were wasted opportunities or wishes to turn back the clock, despair and bitterness can develop.

Individuals with integrity attain wisdom, even when confronting death. Even though this is a positive reaction to aging, there is danger in being too wise. Maladaptation can result when a person avoids reality by acting young without acknowledging the difficulties of aging. The opposite effect called malignancy can happen when a person is preoccupied with regrets and past mistakes. In this state, one loses interest in life’s activities and appears to not care about life anymore. Neither one of these reactions are ideal. Finding a balance between maladaptation and malignancy leads to wisdom, the understanding of your life’s actions, and the acceptance of the outcome.

“The questions as to who is bigger and who can do or not do this or that, and to whom—these questions fill the adult's inner life far beyond the necessities and the desirabilities which he understands and for which he plans."
- Erik H. Erikson (1902–1994)