Online Bachelors Degree in Adult Psychology: According to Erik Erikson's stages of human development, first enumerated in Childhood and Society (1950), a young adult is generally a person between the ages of 20 and 40, whereas an adolescent is a person between the ages of 13 and 19, although definitions and opinions vary. The young adult stage in human development precedes middle adulthood. A person in the middle adulthood stage is between the ages of 40 and 65. In maturity, a person is 65 years old or older.
