Piaget’s Theory of Cognitive Development

Piaget’s cognitive development theory explains how children’s mental models of the world are constructed. Part of the basis for this theory is that intelligence is not a fixed trait and that cognitive development occurs during physical maturation and through environmental interaction.

Piaget was employed to develop French versions of English intelligence test questions by the Binet Institute in the 1920s. He was intrigued by the reasons behind children’s wrong answers to logic-driven questions. To Piaget, the incorrect answers showed that adults and children think in different ways. In 1936, Piaget became the first psychologist to systematically study cognitive development. Through his studies, Piaget developed a theory of the stages of cognitive development in children, as well as a series of tests that demonstrated children’s different cognitive capabilities.

Piaget was not interested in testing basic skills like spelling and counting as a means of determining children’s I.Q. Instead, he sought to understand how children develop concepts like time, quantity, justice and so on. Before Piaget’s studies, it was generally assumed that children possessed the same cognitive skills as adults but were simply less competent. Piaget showed that young children actually think in completely different ways when compared to adults.

By Piaget’s assertion, all children are born with a very basic mental composition. This composition forms the basis on which all consequent learning is built.

The Differences in Piaget’s Theory

The theory developed by Piaget was unique in that:

  • It was the first to be concerned with only children and not all learners.
  • It focused on development instead of children’s ability to learn specific information or behaviours.
  • It was the first to look at development as a series of discrete stages. These stages could be checked by observing qualitative differences in a child’s behaviour that marked new ways of thinking.

Piaget developed his theory with the goal of explaining how children develop from people with limited mental capabilities into adults who are capable of complex mental processes like critical thinking and the forming of hypotheses.

He saw development as a progressive mechanism that involved the reorganisation and transformation of the unique mental processes of a child as a direct result of both physical maturation and environmental experience.

The Three Basic Components of Piaget’s Cognitive Theory

The three basic components are:

  1. Schemas
  2. Assimilation, accommodation and equilibration
  3. The stages by which cognisance develops:
    -Concrete operational
    -Formal operational


Try and imagine being unable to construct a mental model of the world. Without one, it becomes impossible to make use of most of the information anyone has available. For instance, it becomes impossible to make a plan for the future based on knowledge of the past. Schemas are the basic building blocks which form these mental models.

Piaget defined schemas as repeatable and cohesive actions made up of component actions woven together and directed by a core meaning.

This means that Piaget saw schemas as the fundamental unit that comprises intelligent behaviour. The easiest way to think of a schema is as a unit of knowledge. Each schema relates to precisely one aspect of the world such as objects, abstract concepts or actions.

In 2004, Wadsworth proposed that a schema functions like a kind of index card for the brain. When the brain processes incoming information or stimuli, it looks up the corresponding schema and triggers the appropriate response.

When Piaget discussed the ways in which a person’s mental processes develop, he meant the ways in which the complexity and number of schemas a person has learned increase.

When children are capable of perceiving the world around themselves according to their existing schemas, Piaget said that they were in a state of equilibrium.

In his theory, Piaget placed great emphasis on the importance of schemas and their role in cognitive development. One approach to schemas is as a set of depictions of the world. People store these representations and then call upon them when the information contained is relevant.

As an example, someone can have a schema for buying groceries. This schema contains a sequence of actions such as going to a shop, picking up a basket, searching for items, placing the correct items in the basket, taking all the items to the checkout, paying for them and then taking them home. This type of schema is known as a ‘script’. Whenever someone needs to buy groceries, they can utilise this schema and follow the instructions stored in their memory.

Piaget’s schemas are usually much simpler than this, especially the ones commonly utilised by infants. He discussed the process by which schemas grow more numerous and more elaborate as children get older.

According to Piaget, babies are born with a few innate schemas, even without any experiences to base them on. These schemas can be seen in the ways in which all infants have the same innate reflexes. These reflexive behaviours are preprogrammed into everyone on a genetic level.

For instance, babies will suck on almost anything that touches their lips. They will suck on a nipple, a dummy or even something like a person’s finger. Upon observing this common behaviour, Piaget decided that babies have an innate ‘sucking schema’. The same can be said for the grasping schema that is triggered when an object touches the palm of a baby’s hand. A more complex motion, like a baby shaking a rattle, can be thought of as the combination of the grasping schema and the shaking schema.

Assimilation, Accommodation and Equilibration

Piaget saw intellectual growth as the process by which people adapt or adjust to their surrounding world. The process of adaptation occurs through assimilation, accommodation and then equilibration.

Assimilation: The process of utilising an existing schema when dealing with a new situation or object.

Accommodation: The process of changing existing schema or knowledge when its application is not adequate when dealing with the new situation or object.

Equilibration: The process by which development is moved onto the next stage. According to Piaget, cognitive development would occur in sudden leaps rather than at a constant rate. A child reaches equilibrium when their schemas are capable of dealing with most new situations at the assimilation stage of the process. However, when there are no existing schemas available to deal with new information, when the assimilation stage fails, it causes an uncomfortable feeling of disequilibrium.

When the learning process fails, equilibration is the force which drives a person to restore balance by learning whatever is required to overcome the challenge. Once sufficient information has been acquired, the assimilation stage becomes adequate for dealing with new situations until the next time that a change is required.

The 4 Stages of Cognitive Development

Piaget suggested in his theory of cognitive development that children progress through four distinct stages. Each one reflects an increase in the sophistication and complexity of a child’s thought processes.

His theory of development looks at how children acquire knowledge about certain abstract concepts as they age. The concepts Piaget was particularly interested in included object permanence, counting ability, categorization skills, quantity, causality and an idea of justice.


Piaget called these four stages:

  1. Sensorimotor: Generally lasts from birth until 18 to 24 months.
  2. Preoperational: Generally lasts from the end of the sensorimotor stage until age 7.
  3. Concrete operational: Generally lasts from the end of the sensorimotor stage until 7 to 11 years.
  4. Formal operational: Lasts from the end of the concrete operational stage and extends throughout adulthood.


All children progress through these stages in the same order. For further information on this see the Child & Family Blog

While it is impossible for a child to skip any of these stages, different children progress through the stages at differing rates. It is even possible for some children to never obtain the final stages.

Piaget never claimed that children were guaranteed to reach any of the stages at a particular age. Instead, he used age as an average indication of when children could be expected to reach any given stage.

Sensorimotor Stage (From birth to 2 years):

During the sensorimotor stage, infants develop the concept of object permanence. This means they understand that an object continues to exist when they cannot see it. Doing so requires the ability to form a schema around an object.


Preoperational Stage (From 2 to 7 years): During the preoperational stage, children develop the ability to represent objects or concepts via symbols. This is the time during which children develop an understanding of how numbers represent quantity.


Concrete Operational Stage (From 7 to 11 years): During the concrete operational stage, children become capable of operational and logical thought processes. This is the point at which an individual becomes capable of simulating a situation mentally instead of requiring physical objects to test their theories. During this stage, children develop the ability to conserve number, mass and weight. This means that they understand that these characteristics can remain the same as an object’s appearance changes.


Formal Operational Stage (From 11 years onwards): During the formal operation stage, people become capable of conceptualising the most abstract concepts. They also develop the ability to form and then test a hypothesis using logical methodologies.

The influence of Piaget’s ideas in developmental psychology has been enormous.

He has changed how people view the child’s world and their methods of studying children.

Jean Piaget’s work has helped people understand how knowledge is developed at different stages of childhood.