1 Psychology and human development1.3 Learning and learning theories
1.3.6 Cognitive development
6 min read3 figures
Written by Resident Doctor Committee · Published
Piaget's stage theory
Piaget originated the stage theory of cognitive development, which describes how reasoning itself matures through four stages. In his model, children actively construct knowledge.
Stage | Approximate age | Central achievement |
|---|---|---|
Sensorimotor | Birth to 2 years | Object permanence |
Preoperational | 2 to 7 years | Semiotic (symbolic) function |
Concrete operational | 7 to 11 years | Conservation |
Formal operational | From about 11 or 12 years | Hypothetico-deductive thought |
The preoperational stage has a preconceptual substage that gives way to an intuitive substage at about 4 years.
Piaget's stages are cognitive. Erikson's stages are psychosocial, Kohlberg's are moral and Freud's are psychosexual.
How schemas change
A schema is the organised unit of knowledge, built from past experience, on which cognitive development works.
Assimilation is making sense of new experience by fitting it into an existing schema without changing the schema.
Accommodation is modifying an existing schema when new experience does not fit it, as when learning that a cow is not a dog alters the dog schema.
Adaptation is the umbrella term for assimilation and accommodation.
Disequilibrium is the imbalance that appears when assimilation fails because experience does not fit current schemas, and its discomfort motivates change.
Equilibration is the self-regulating process that coordinates assimilation and accommodation to resolve disequilibrium and restore balance. It operates across all stages.
Sensorimotor stage
Understanding develops through perception and action, moving towards intentional behaviour and mental representation.
Substage | Age | Achievement |
|---|---|---|
1 Reflex activity | 0 to 1 month | Exercises innate reflexes |
2 Primary circular reactions | 2 to 4 months | Repeats a chance action centred on the infant's own body, for its own sake |
3 Secondary circular reactions | 4 to 8 months | Repeats one unchanged action to reproduce an effect on an external object |
4 Coordination of secondary circular reactions | 8 to 12 months | Links two familiar schemes intentionally, as means to an end |
5 Tertiary circular reactions | 12 to 18 months | Deliberately varies actions on objects to see new outcomes: the small experimenter |
6 Representational thought | 18 to 24 months | Deferred imitation, symbolic play and secure object permanence |
Object permanence
Object permanence, understanding that objects exist when not perceived, is the central achievement of the sensorimotor stage. It is not a preoperational feature.
Infants retrieve partly hidden objects earlier, but they first search for a completely hidden toy at about 8 to 9 months (substage 4).
The A-not-B error is searching the old hiding place despite seeing the object moved elsewhere.
Object permanence is secure by about 18 to 24 months.
Baillargeon's looking-time studies suggested expectations about hidden objects at 3 to 4 months, because search tasks also demand memory, motor control and inhibition.
Other sensorimotor achievements
Deferred imitation, copying a model who is no longer present, shows a stored mental image and representational thought in substage 6.
Piaget placed the earliest, primitive differentiation of self from the world in this stage, alongside the start of symbolisation at about 18 months.
Preoperational stage
Symbols now support language, drawing and pretend play, but mental operations are not yet reversible.
The semiotic (symbolic) function, one thing standing for something absent, shows in pretend play when one object substitutes for another.
Egocentrism, failing to separate one's own viewpoint from another's, is the defining limitation of this stage. It is not selfishness.
On Piaget's three mountains task, the egocentric child picks their own view as the doll's view.
Centration is attending to one salient feature and ignoring the rest, so a spread-out row of counters seems to hold more.
Animism is crediting lifeless objects and natural events with life, feelings and intentions.
Artificialism is the belief that natural things were made by people.
Phenomenalistic causality is assuming that events occurring together in time cause one another, such as blaming an angry thought for an illness.
Transductive reasoning goes from one particular case to another without a general rule, whereas inductive reasoning ends in a general rule.
Human figure drawing gives a non-verbal, age-normed estimate of a young child's cognitive ability, because detail and proportion grow in a predictable order between about 3 and 6 years.
Concrete operational stage
Conservation, understanding that quantity is unchanged by a change in appearance, is the hallmark achievement of this stage. Preoperational children fail it because they judge by one dimension, such as the height of liquid in a glass.
Reversibility and decentration, attending to several features at once, are the two abilities that make conservation possible.
Children of this age also manage classification, seriation and syllogistic reasoning from given, concrete premises.
Understanding puns and riddles, which need two meanings held at once, emerges in this stage.
Conservation of | Approximate age acquired |
|---|---|
Number | 5 to 6 years |
Mass and liquid quantity | 6 to 7 years |
Length and area | 7 to 8 years |
Weight | 9 to 10 years |
Volume | 11 to 12 years |
Horizontal decalage is applying an operation successfully in one domain before another, which challenges strict stage boundaries.
Formal operational stage
Formal operational thought, from about 11 years through adolescence, is hypothetico-deductive and abstract: it works on hypothetical, contrary-to-fact possibilities and tests hypotheses systematically.
In the pendulum task, the adolescent varies one factor at a time to identify the cause.
Concrete operational logic is tied to real objects, whereas formal operational logic can work on propositions and possibilities.
Its use depends on education, familiarity and context, and even adults do not reason formally in every domain.
Later theorists matched the maturity hierarchy of defences to Piaget's stages, placing neurotic defences such as intellectualisation with the formal operational stage.
Criticisms of Piaget
Simpler or more meaningful tasks often reveal abilities earlier. Development is less uniform than fixed stages imply, and the model underplays teaching and culture.
Original task | Simplified version | Finding |
|---|---|---|
Three mountains | Hughes's policeman doll task | Younger children show perspective taking |
Conservation | McGarrigle and Donaldson's naughty teddy | Accidental rearrangement reduces misleading task demands |
Vygotsky
Vygotsky's sociocultural theory holds that cognitive development is shaped by culture and social interaction, and so varies between cultures.
The zone of proximal development is the gap between what a child achieves alone and what the child achieves with guidance from an adult or more capable peer.
The functions in the zone of proximal development are maturing but still need help.
Scaffolding, associated with Bruner, is support that is gradually withdrawn.
Private (self-directed) speech helps children plan and regulate their own actions. It appears at about 3 years and goes underground as silent inner speech by about 7.
Communicating at the person's level of thought
With concrete thinkers, use short literal sentences, one idea at a time, familiar objects or pictures, and time linked to events such as "after lunch".
Clinicians should assess individual needs rather than assign a childhood stage to someone because of disability, dementia or illness.
Age or articulate speech alone does not establish understanding or decision-making capacity.