AP Psychology Unit 3 Notes: Developmental Psychology (From Conception Through Adulthood)

Developmental psychology

The study of how and why people change across the lifespan physically, cognitively, and socially.

Germinal stage

The first couple of weeks after conception when the fertilized egg divides rapidly, becomes a blastocyst, and implants in the uterine wall.

Embryonic stage

Prenatal period (about weeks 2–8) when major organs begin forming and the basic body plan develops; a high-risk period for teratogen effects.

Fetal stage

Prenatal period (about week 9 to birth) marked by dramatic growth in size and continued maturation of body systems, especially the brain.

Teratogen

Any substance or environmental factor that can harm prenatal development; effects depend on dose, timing, and genetic vulnerability.

Fetal alcohol syndrome (FAS)

A pattern of outcomes linked to heavy prenatal alcohol exposure, often including growth problems and brain-based impairments.

Newborn reflexes (rooting and sucking)

Automatic, inborn responses that support survival; rooting is turning toward a cheek touch, and sucking occurs when something touches the lips.

Schema

A mental framework used to organize and interpret information (e.g., a category or routine like “dog” or “bedtime”).

Assimilation

Interpreting a new experience by fitting it into an existing schema (using an old category without changing it).

Accommodation

Adjusting an existing schema or forming a new one when new information doesn’t fit; often drives major conceptual change.

Sensorimotor stage

Piaget’s stage from birth to about age 2 in which infants learn through senses and actions and gradually develop mental representations.

Object permanence

The understanding that objects continue to exist even when they cannot be seen; a key development in the sensorimotor stage.

Preoperational stage

Piaget’s stage (about ages 2–7) marked by rapid language and symbol use, but limited logical operations; conservation is typically difficult.

Egocentrism (Piaget)

A cognitive limitation common in the preoperational stage involving difficulty taking another person’s perspective (not the same as selfishness).

Conservation errors (centration and reversibility)

Preoperational mistakes in judging quantity because children focus on one feature (centration, like height) and struggle to mentally undo a change (reversibility).

Concrete operational stage

Piaget’s stage (about ages 7–11) when children can perform logical operations on concrete objects and typically understand conservation.

Formal operational stage

Piaget’s stage (about age 12 and up) involving abstract and hypothetical reasoning; having the capacity does not guarantee perfect logic in all situations.

Zone of proximal development (ZPD)

Vygotsky’s concept: the range between what a learner can do independently and what they can do with guidance.

Scaffolding

Temporary, adjustable support (e.g., hints, modeling, breaking steps down) that helps a learner succeed in the ZPD and is gradually removed.

Trust vs. mistrust

Erikson’s infancy stage focused on whether caregivers are reliable; successful resolution supports a sense of safety and predictability.

Secure attachment

An attachment pattern where an infant uses the caregiver as a secure base, may protest separation, and is soothed when the caregiver returns.

Contact comfort

The calming value of soft touch and warmth in attachment (highlighted by Harlow’s monkey studies), showing comfort is a powerful driver of attachment behavior.

Fluid vs. crystallized intelligence

Fluid intelligence is quick reasoning and solving novel problems (tends to decline with age); crystallized intelligence is accumulated knowledge and verbal skills (often stays stable longer or improves).

Kohlberg’s levels of moral reasoning

Three levels describing the logic behind moral judgments: preconventional (punishment/reward), conventional (approval/law and order), and postconventional (social contract/universal principles).

Ethic of care (Gilligan)

An approach to moral reasoning that emphasizes relationships, empathy, and responsibility for others, complementing justice/rights-focused reasoning.