cognitive development

Meaning: Cognitive development is how thinking, memory, language, and reasoning change across the lifespan. In Piaget's account, children build schemas and revise them by assimilation (fitting new information into an existing schema) or accommodation (changing the schema to fit new information). Approximate stages: sensorimotor (birth to about 2; object permanence), preoperational (about 2 to 7; symbolic thought, egocentrism, no conservation), concrete operational (about 7 to 11; conservation, logic about concrete objects), formal operational (about 12 onward; abstract and hypothetical reasoning). Vygotsky's sociocultural account instead stresses social interaction, in which a more skilled partner helps a child work within the zone of proximal development.

On the MCAT: A passage describes a child's behavior and you name the stage. A child who searches for a hidden toy shows object permanence (sensorimotor). A child who says a tall, thin glass holds more than a short, wide one fails conservation (preoperational). Questions may also ask whether an example is assimilation or accommodation.

Common confusion: Students swap assimilation and accommodation. The schema changes only in accommodation. Ages are approximate, and children can differ in timing. Piaget's stages are also not Kohlberg's moral stages or Erikson's psychosocial stages.