Stage theories: stop memorizing them one at a time.
Piaget, Erikson, Kohlberg and the others line up by age. Learn them as one table and the items get easy.
By Dr. Andrew Wichterman · September 14, 2026 · 5 min read · Updated October 5, 2026
Human Growth and Development items usually give you an age or a behavior and ask which stage, or which theorist. Students who learned each theory separately have to search four mental lists. Students who learned them as one table read across a row. Build the table.
The row structure
Down the left side, age bands: infancy, toddlerhood, early childhood, middle childhood, adolescence, early adulthood, middle adulthood, late adulthood. Across the top, the theorists. Fill each cell with the stage name and its one distinguishing behavior.
- Piaget (cognitive): sensorimotor, preoperational, concrete operational, formal operational. Key behaviors: object permanence, egocentrism and centration, conservation, abstract reasoning.
- Erikson (psychosocial): eight crises from trust vs. mistrust to integrity vs. despair. The exam tests the crisis name and the age.
- Kohlberg (moral): preconventional, conventional, postconventional, each with two stages. Tested through short dilemmas: what reason does the person give?
- Freud (psychosexual): oral, anal, phallic, latency, genital. Still appears, usually as a contrast to Erikson.
- Vygotsky: not stages, but the zone of proximal development and scaffolding. Appears when the stem mentions a more capable peer or adult.
The table, filled in
Infancy, birth to about two: Piaget's sensorimotor stage, ending with object permanence; Erikson's trust versus mistrust; Freud's oral stage. Toddlerhood, two to three: preoperational begins; autonomy versus shame and doubt; the anal stage. Early childhood, three to six: preoperational, with egocentrism, centration and animism; initiative versus guilt; the phallic stage with the Oedipal conflict; Kohlberg's stage one, obedience and punishment. Middle childhood, six to twelve: concrete operations, with conservation, reversibility and classification; industry versus inferiority; latency; Kohlberg moving from stage two, self-interest and exchange, into the conventional level.
Adolescence, twelve to eighteen: formal operations, with hypothetical and abstract reasoning and the adolescent egocentrism Elkind described as the imaginary audience and personal fable; identity versus role confusion; the genital stage; Kohlberg's conventional stages three, good-boy good-girl, and four, law and order. Early adulthood: intimacy versus isolation. Middle adulthood: generativity versus stagnation. Late adulthood: integrity versus despair. Postconventional morality, stages five and six, is reached by a minority of adults, and Kohlberg eventually doubted that stage six could be measured. Read across any row and the item is answered.
Neighbors that get mixed in
Marcia extended Erikson's identity stage into four statuses defined by whether exploration and commitment have occurred: diffusion, neither; foreclosure, commitment without exploration; moratorium, exploration without commitment; achievement, both. An item about an adolescent who adopted the parents' career plan without considering alternatives is foreclosure, not identity achievement. Gilligan answered Kohlberg with an ethic of care, arguing his justice-based stages undervalued relational reasoning; her levels move from self-interest through care for others to a balance of the two.
Havighurst framed each period by developmental tasks rather than crises. Levinson described adult life as alternating stable periods and transitions, with the midlife transition around forty. Loevinger traced ego development, Fowler traced faith development, and Kegan traced orders of consciousness; these appear rarely and usually as distractors. When an item names a theorist you have not placed, the question to ask is whether the stem describes thinking, feeling about the self, moral reasoning or a task, because that tells you which column of the table the item is drawing from.
The items that separate students
Most misses in this area are one row off. The stem says a child can conserve volume, and the student picks preoperational because the child is described as seven. Read the behavior before the age. Behavior is the evidence; age is the approximation.
For Kohlberg, the stem gives a reason, not an action. Two people can make the same choice at different stages. "Because I would get punished" is preconventional. "Because it is the law" is conventional. "Because of a principle that applies to everyone" is postconventional.
Three items, worked
A four-year-old insists that her brother has more juice because his glass is taller, though both were poured from the same measuring cup. The behavior is centration and a failure of conservation: preoperational. The age confirms it, but the behavior decides it. A nine-year-old refuses to cheat on a test "because the teacher said it is against the rules and I would get in trouble." Punishment avoidance plus authority: Kohlberg's preconventional stage one, despite an age at which many children are moving into conventional reasoning. The reason given, not the age, is the evidence.
A sixty-eight-year-old recently retired client describes reviewing his career and feeling that most of it was wasted and that it is too late to change anything. Erikson's integrity versus despair, resolved toward despair. The distractor will be generativity versus stagnation, which belongs to the working years and concerns contribution to the next generation. If the client were fifty and worried about leaving nothing behind, that would be the answer; at sixty-eight and looking back, it is not.
Adult development and aging
Do not stop at adolescence. Erikson's adult stages, Levinson's seasons, and the basic facts about cognitive aging (crystallized intelligence holds; fluid intelligence declines) appear regularly. Grief models (Kübler-Ross, Worden's tasks) also live here.
Attachment
Ainsworth's strange situation and the four attachment patterns come up as descriptions of a toddler's behavior on reunion. Secure, avoidant, ambivalent/resistant, disorganized. Know the reunion behavior for each.
One table, reviewed weekly, replaces four chapters. That is the whole method.