This is the most-viewed and most-cited page on the site. Unfortunately.

  • The site is principally about post-16 learning and teaching. From that point of view the most interesting aspect of Piaget's work are the ideas of assimilation and accommodation.
  • This page was added simply to put those ideas in some minimal context. It does not set out to provide a comprehensive account of Piaget's ideas. It is grossly over-simplified. To cite it for any purpose other than its intention is to dumb down.
  • And Piaget has been overtaken in many areas anyway. It is the fate of great scholars, researchers and innovators to ask the great questions but produce the wrong answers...

Piaget's Key Ideas

Stages of Cognitive Development

Jean Piaget (1896-1980) was a biologist who originally studied molluscs (publishing twenty scientific papers on them by the time he was 21) but moved into the study of the development of children's understanding, through observing them and talking and listening to them while they worked on exercises he set.

"Piaget's work on children's intellectual development owed much to his early studies of water snails"

(Satterly, 1987:622)

His view of how children's minds work and develop has been enormously influential, particularly in educational theory. His particular insight was the role of maturation (simply growing up) in children's increasing capacity to understand their world: they cannot undertake certain tasks until they are psychologically mature enough to do so. His research has spawned a great deal more, much of which has undermined the detail of his own, but like many other original investigators, his importance comes from his overall vision.

He proposed that children's thinking does not develop entirely smoothly: instead, there are certain points at which it "takes off" and moves into completely new areas and capabilities. He saw these transitions as taking place at about 18 months, 7 years and 11 or 12 years. This has been taken to mean that before these ages children are not capable (no matter how bright) of understanding things in certain ways, and has been used as the basis for scheduling the school curriculum. Whether or not should be the case is a different matter.


Piaget's Key Ideas

Adaptation  What it says: adapting to the world through assimilation and accommodation 
Assimilation  The process by which a person takes material into their mind from the environment, which may mean changing the evidence of their senses to make it fit. 
Accommodation  The difference made to one's mind or concepts by the process of assimilation. 
Note that assimilation and accommodation go together: you can't have one without the other. 
Classification  The ability to group objects together on the basis of common features. 
Class Inclusion  The understanding, more advanced than simple classification, that some classes or sets of objects are also sub-sets of a larger class. (E.g. there is a class of objects called dogs. There is also a class called animals. But all dogs are also animals, so the class of animals includes that of dogs) 
Conservation  The realisation that objects or sets of objects stay the same even when they are changed about or made to look different. 


The ability to move away from one system of classification to another one as appropriate.

Egocentrism  The belief that you are the centre of the universe and everything revolves around you: the corresponding inability to see the world as someone else does and adapt to it. Not moral "selfishness", just an early stage of psychological development. 
Operation  The process of working something out in your head. Young children (in the sensorimotor and pre-operational stages) have to act, and try things out in the real world, to work things out (like count on fingers): older children and adults can do more in their heads. 
Schema (or scheme)  The representation in the mind of a set of perceptions, ideas, and/or actions, which go together. 
Stage  A period in a child's development in which he or she is capable of understanding some things but not others 

Stages of Cognitive Development

Stage  Characterised by 
(Birth-2 yrs) 
Differentiates self from objects 

Recognises self as agent of action and begins to act intentionally: e.g. pulls a string to set mobile in motion or shakes a rattle to make a noise 

Achieves object permanence: realises that things continue to exist even when no longer present to the sense (pace Bishop Berkeley) 

(2-7 years) 
Learns to use language and to represent objects by images and words 

Thinking is still egocentric: has difficulty taking the viewpoint of others 

Classifies objects by a single feature: e.g. groups together all the red blocks regardless of shape or all the square blocks regardless of colour 

Concrete operational 
(7-11 years) 
Can think logically about objects and events 

Achieves conservation of number (age 6), mass (age 7), and weight (age 9) 

Classifies objects according to several features and can order them in series along a single dimension such as size. 

Formal operational 
(11 years and up) 
Can think logically about abstract propositions and test hypotheses systemtically 

Becomes concerned with the hypothetical, the future, and ideological problems 

The accumulating evidence is that this scheme is too rigid: many children manage concrete operations earlier than he thought, and some people never attain formal operations (or at least are not called upon to use them).

Piaget's approach is central to the school of cognitive theory known as "cognitive constructivism": other scholars, known as "social constructivists", such as Vygotsky and Bruner, have laid more emphasis on the part played by language and other people in enabling children to learn.

See here for Howard Gardner's re-evaluation of Piaget: still a giant, but wrong in practically every detail.

And the combination of neuroscience and evolutionary psychology is beginning to suggest that the overall developmental model is based on dubious premises. (It's too early to give authoritative references for this angle.)

Piaget Reading

DONALDSON M (1984) Children's Minds London Fontana (readable and critical) 

SATTERLY D (1987) "Piaget and Education" in R L Gregory (ed.) The Oxford Companion to the Mind Oxford, Oxford University Press  [back]

WOOD D (1998) How Children Think and Learn (2nd edition) Oxford; Blackwell Publishing.

(up-dated 18.09.11)

To reference this page copy and paste the text below:

Atherton J S (2013) Learning and Teaching; [On-line: UK] retrieved from

Original material by James Atherton: last up-dated overall 10 February 2013

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