Piaget’s Stages of Cognitive Development

Subject: Psychology
Pages: 7
Words: 1674
Reading time:
6 min
Study level: College


Jean Piaget was born in Switzerland in 1896. In his youth, he studied philosophy and obtained a doctorate in biology by the age of 21. In his work in biology, he discovered that mollusks could adapt to different environments and that their shells matured differently according to their environment. This discovery led him to consider how humans might adapt and mature differently according to their environment. This new area of interest led him to study developmental psychology and he went on to become one of the most respected and influential figures in the field.

The majority of his work in psychology and that which he is most famous for is his theory of cognitive development. Piaget believed that children were born with an innate desire (and need) to adapt to their environment and that they do this by interacting with it and learning from it. He came up with the idea of ‘schemas’ which are the basic building blocks of intelligence. Babies start with minimal in-built schemas for things such as sucking and grasping and moving limbs. As the baby grows its schemas are refined and combined to create more complex schemas such as for walking. This development takes place through the processes of ‘assimilation’, ‘accommodation’, and ‘equilibrium’ (Bryant, 1995). A baby will try and apply its schema of sucking its mother’s nipple to obtain nutrients to sucking a cup of juice; this is the baby’s attempt to assimilate the task of drinking from a cup into its existing schemata. The sucking schema is inadequate for the task and the child will be in a state of disequilibrium. To restore balance the child must modify its existing schemas to accommodate the new task or experience. This is the process of ‘adaptation’ (McIlveen, 1997).

Piaget identified four main stages of cognitive development through which all children pass as they grow older. Each stage is typified by the kind of schemas a child has within that stage. The intellectual understanding attained at each stage builds upon that of the previous stage, and the stages are therefore passed through in sequence. Development remains continuous and fluid through all the stages, however, rather than jumping from one stage to the next.

The sensorimotor stage

The first stage is called the sensorimotor stage. This stage occupies approximately the first two years of the child’s life. It is characterized by the child’s hands-on approach to discovering the world around it. The child learns by hearing, seeing, smelling (sensory), and grasping, sucking, and pulling (motor). The first few months are also characterized by the baby’s lack of ‘object permanence (Gross, 1992). This means that the child is not able to understand that when an object is removed from view the object still exists. To the child, if an object is out of sight it is out of mind. The child is also extremely egocentric; it is unable to make the distinction between itself and the world around it (Pulaski, 1980).

The preoperational stage

The second stage in Piaget’s theory of cognitive development is the preoperational stage which lasts from the ages of 2 to 7 years old. During this stage, the child greatly develops the ability to use symbols and language. Although the child learns to distinguish between itself and the rest of the world it is still egocentric in that it is unable to see things from other people’s point of view or to ‘put itself in other people’s shoes.

The concrete operational stage

The next stage is called the concrete operational stage which lasts from 7 to 11 years of age. This stage is where the child acquires the ability to perform logical operations. These cognitive operations allow the child to make logical deductions that are not dependant on their perceptions although they still need grounding in concrete experience. These logical operations are also fully reversible allowing the child to consider a lot of possibilities. The child also becomes a great deal less egocentric, allowing it to become a lot more sociable and consider various points of view (McIlveen, 1997).

The formal operational stage

The fourth and final stage is the formal operational stage which develops from the age of 11 to the age of 16. During this stage, the child’s ability to perform logical operations continues to grow and is freed from the need for the experience of the object or situation (Pulaski, 1980). This enables the child to think in more abstract terms allowing them to consider hypothetical situations as well as real experiences. The child also becomes capable of ‘reflective abstraction’ which allows them to acquire new knowledge by considering and reflecting upon existing knowledge.

Criticism of theory

Piaget’s theory is coherent and offers a complete and detailed model of intellectual development from birth to adulthood. It is the most well-known and possibly the most established theory of its kind. It is also one of the most controversial. Many psychologists have criticized Piaget’s theory, especially about the manner of the experiments he used to explore and prove his theories (Bryant, 1995).

One of the first criticisms of Piaget’s work is that he often only used his own three children as test subjects for his experiments. This could introduce several confounding variables and problems with the validity of the results. First of all the use of only three participants for any kind of experiment is too small, especially when the results are to be applied to the whole world. Any kind of anomalies or unusual traits of his three children would be magnified. (Wadsworth, 1989) For instance, if one of his children was able to perform a particular mental operation at a very young age, this could be interpreted as meaning a third of the whole world’s children would be able to do the same, even though only a tiny proportion actually could (Gruber, 1977).

Another problem with Piaget’s use of his children is that there were many things in the children’s lives and environment which would be unique to them. An important example of this is the fact that their father was one of the world’s leading scientists! How many people in the world can say that? This means that Piaget’s great intelligence would have probably been passed on to his children in some way, either through genetics or through his interaction with them as they grew up (McIlveen, 1997). This means that they may have been more intellectually developed than the average child of their age and they would also be familiar with their father’s way of thinking and communicating, perhaps helping them to perform better in his experiments (Gross, 1992). Although Piaget’s theory is fundamentally based largely on his observations of his children, it is worth noting that he also performed larger scale experiments and some of his earlier work with his children was re-tested by himself and others with not too dissimilar results.

Piaget has also been criticized for the wording he used during his experiments. Some say that his wording was often too advanced, abstract, or ambiguous for the child to understand what is required of them. There is also the issue of what each child understands of certain words (McIlveen, 1997). For instance, when performing a liquid conservation experiment, Piaget would ask the child if one glass had more water in it than the other. Would the child have the same understanding of the word ‘more’ as ‘three-dimensional volume’ that Piaget would have? The child may interpret this as meaning ‘does one glass have more height of water in it. If so, then this is a different problem of cognition and does not necessarily mean that the child does not grasp the concept of conservation.

Much of Piaget’s work was based on observations, usually of his children, which were non-experimental and recorded in a qualitative, yet systematic and comprehensive way. He saw this as the best way to solve the puzzles of cognitive development which concerned him. This kind of procedure produces results that are not easily analyzed and do not give definitive ‘black and white answers. The data he gathered is therefore open to some interpretation (Pulaski, 1980).

Piaget’s theory that children aged below seven are intrinsically egocentric has also been cast into serious doubt. Whilst it is generally agreed that youngsters are egocentric to some extent, it has been observed that children as young as four can choose suitable gifts for their mother’s birthday, rather than (as Piaget would have expected) buying toys that they would like. It has also been shown that children as young as four can use ‘child-contingent’ language to talk to younger children, meaning that they modify their language making it less complex so that it can be understood by the toddler.


There are many flaws in Piaget’s theory of cognitive development and perhaps even more flaws in the methodology he used to explore and verify it. The volume of criticism that this has generated has left very few people who still entirely agree with Piaget’s theory. Many people dispute his theory as a whole. This revolt however does not necessarily mean that Piaget’s contribution to the field of cognitive development is invalidated, in fact, in some ways it only serves to highlight how important his work has become.

All other alternative theories of cognitive development stem from or are inspired by Piaget’s work in one way or another. Some are an attempt to build on or refine his disputed theories into a more practical or rational explanation. Many new theories are a reaction to Piaget’s, very much at odds with his ideas and often from an opposite viewpoint (such as Vygotsky). If Piaget had not formed and published his theories on cognitive development then Vygotsky and other theorists may never have come to offer their alternative views and the subject of cognitive development may not have been researched nearly as much as it has been to date. For this reason, even if Piaget’s theories are eventually largely dismissed or disproved, his contribution to the subject should still be considered of great importance.


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  2. Gross R. D. (1992) “Psychology: The Science of Mind and Behaviour, 2nd Ed. Hodder & Stoughton.
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