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# Piaget's stages of cognitive development

- Theory

Piaget described how children think differently at each age: by acting, by symbols, by concrete logic and finally by abstract logic.

Updated Nov 5, 2026

## Key points

- Sensorimotor (0 to 2 years): learning by senses and actions; object permanence; ends with the start of symbolic thought.
- Preoperational (2 to 7): symbols, language and pretend play; egocentrism, animism, magical thinking; no conservation.
- Concrete operational (7 to 11): logic about concrete things; conservation, reversibility, classification.
- Formal operational (11 and up): abstract and hypothetical reasoning; not reached by everyone in every area.
- Assimilation fits new information into a schema; accommodation changes the schema.
- Critiques: development is more continuous, children show skills earlier, and culture and schooling matter more than he allowed.

## What it is

Jean Piaget proposed that children build knowledge actively, organizing experience into mental frameworks (schemas). New information is either fitted into an existing schema (assimilation) or forces the schema to change (accommodation), and the balance between the two (equilibration) drives development. He described four stages, each with a typical way of thinking; the ages are approximate, and later research shows children often reach these skills earlier and more gradually than he thought.

## Key facts

- Object permanence (knowing that a hidden object still exists) appears in the second half of the first year.
- Conservation is the understanding that the amount of liquid does not change when it is poured into a taller, thinner glass.
- Egocentrism in this sense means being unable to take another person's viewpoint, not selfishness.
- Vygotsky added the social side: children learn best in the zone of proximal development, with help from more skilled people.

## Piaget's four stages

| Stage (approximate age) | How the child thinks | Key achievements | Limits |
| --- | --- | --- | --- |
| Sensorimotor (0 to 2 years) | Through senses and movement | Object permanence; deliberate actions; deferred imitation | No mental representation at first |
| Preoperational (2 to 7 years) | With symbols, words and pretend play | Language; symbolic play | Egocentrism; animism; centration; no conservation |
| Concrete operational (7 to 11 years) | With logic about concrete objects | Conservation; reversibility; ordering and classification | Difficulty with abstract or hypothetical ideas |
| Formal operational (11 years and up) | With abstract and hypothetical logic | Hypothesis testing; thinking about thinking; abstract ideas | Not used by everyone in every situation |

## Clinical notes

- A preoperational child may believe that illness is a punishment or that a shot is a sign of being bad: explanations should be concrete and reassuring.
- A school-age child understands step-by-step concrete explanations, such as germs entering through a cut.
- Adolescents can reason about future consequences, but under stress or strong emotion they may fall back on more concrete thinking.

## Memory aid

Do, Pretend, Count, Imagine: the child acts, then pretends, then counts real things, then imagines what is possible.

## Test yourself

Think of the answer, then tap the question to see it.

## In which Piaget stage does object permanence appear?

In the sensorimotor stage (0 to 2 years), in the second half of the first year.

## A 5-year-old says the taller glass has more juice after watching it poured from a short wide glass. What does this show?

Lack of conservation, typical of the preoperational stage (2 to 7 years).

## What is the difference between assimilation and accommodation?

Assimilation fits new information into an existing schema; accommodation changes the schema to fit the new information.

## What are the main critiques of Piaget's theory?

Development is more continuous than stage-like, children show many skills earlier, and culture and teaching shape thinking more than he proposed.

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## Elsewhere in DurgiPedia

- [Learning and memory](https://durgical.com/en/physiology/learning-and-memory/)

## Connections

## Related 6

- [Erikson's psychosocial stages](https://durgical.com/en/behavioral-science/erikson-s-psychosocial-stages/)
- [Moral development (Kohlberg)](https://durgical.com/en/behavioral-science/moral-development/)
- [Milestones of the first year](https://durgical.com/en/behavioral-science/milestones-of-the-first-year/)
- [Adolescence: development and the HEADSSS interview](https://durgical.com/en/behavioral-science/adolescence-development-and-the-headsss-interview/)
- [Language development and speech red flags](https://durgical.com/en/behavioral-science/language-development-and-speech-red-flags/)
- [Communication skills: open questions, empathy and teach-back](https://durgical.com/en/behavioral-science/communication-skills-open-questions-empathy-and-teach-back/)

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Educational content on behavior and the clinical relationship; not a diagnostic or treatment guide and no substitute for assessment by a health professional. If you or someone near you is at risk, seek help now from an emergency service or a mental-health helpline.

Sources: [Stages in Theory and Experiment. Fuzzy-Structuralism and Piagetian Stages](https://pmc.ncbi.nlm.nih.gov/articles/PMC9832071/) (Integrative Psychological and Behavioral Science (PubMed Central), 2023); [Children's Understanding of Biology and Health](https://pmc.ncbi.nlm.nih.gov/articles/PMC2533821/) (Canadian Child and Adolescent Psychiatry Review (PubMed Central), 2004).

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Representative model, for educational purposes only.

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