What to know about Piaget’s stages of cognitive development

Piaget’s stages are a theory of how a child’s cognition — meaning their knowledge and understanding about the world — develops between birth and adulthood.

Jean Piaget was an early psychologist who specialized in child development from the 1920s onward. Piaget developed his theories by watching children and making notes about their progress.

The core idea of Piaget’s theory is that children develop by acting as “little scientists” who explore and interact with their world to understand people, objects, and concepts. They do this naturally, even without the help of an adult.

This article explains Piaget’s four stages of cognitive development, key concepts, and how people can use them to help children learn and develop.

Piaget’s stages

This table and the following sections outline Piaget’s four stages of cognitive development:

Stage Age Key information
The sensorimotor stage 0–2 years Infants start to build an understanding of the world through their senses by touching, grasping, watching, and listening.

Infants develop object permanence (see below).

The preoperational stage 2–7 years Children develop language and abstract thought.

Children begin to use symbolic play (“playing pretend”), draw pictures, and talk about things that happened in the past.

The concrete operational stage 7–11 years Children learn logical concrete (physical) rules about objects, such as height, weight, and volume.

Children learn conservation, the idea that an object, such as water or modeling clay, remains the same even when its appearance changes.

The formal operational stage 11+ Children learn logical rules to understand abstract concepts and solve problems.

1. The sensorimotor stage (birth to 2 years)

baby chewing toy
A baby will use their senses to explore the environment.

From birth to 2 years of age, an infant begins to understand the world around them by using their senses and bodily movements. Experts call this the sensorimotor stage.

At first, a baby uses their basic reflex movements, such as sucking and waving their arms, to explore their environment. They also use their senses of sight, touch, smell, taste, and hearing.

As a little scientist, they gather information from these experiences and learn how to differentiate between people, objects, textures, sights, and how different situations make them feel.

Object permanence

The most advanced cognitive achievement a child reaches during this stage is object permanence. Object permanence refers to when an infant understands that an object still exists, even when they are not able to see, smell, touch, or hear it.

Object permanence is important because it means that the infant has developed the ability to form a mental image, or representation, of an object rather than merely reacting to what they experience in their immediate environment.

2. The preoperational stage (2 to 7 years)

In the preoperational stage, a child builds on object permanence and continues to develop abstract ways of thinking. This includes developing sophisticated language skills and using words and behaviors to represent objects or events that they experienced in the past.

The child displays five key behaviors during this period:

  • Imitation. This is where a child can mimic someone’s behavior even when the person they are imitating is no longer in front of them.
  • Symbolic play. A child starts to use objects as symbols, projecting the properties of one object onto another; for example, pretending a stick is a sword.
  • Drawing. Drawing involves both imitation and symbolic play. It begins as scribbles and develops into more accurate abstract representations of objects and people.
  • Mental imagery. The child can picture many objects in their minds. They may ask the names of objects often to secure these associations in their mind.
  • Verbal evocation of events. The child can use language to describe and represent events, people, or objects from their past.

During the preoperational stage, the child is egocentric. This means they only understand the world from their perspective and struggle to see other peoples’ points of view.

3. The concrete operational stage (7 to 11 years)

The concrete operational stage is another major turning point in a child’s cognitive development. The child builds on and masters abstract thought. They become less egocentric and more rational.

During this stage, the child acquires the ability to develop and apply logical, concrete rules to objects (but not to abstract concepts — this comes in the formal operational stage).

This includes a better ability to classify objects into groups and subgroups, the ability to understand logical orders, such as height and weight, and an understanding of conservation.


Conservation is the understanding that an object can change in size, volume, or appearance, but remain the same object.

For example, the appearance of water changes when someone pours it from a short, wide glass into a tall, narrow bottle, but the water itself does not change. The child now understands this.

4. The formal operational stage (11 to adult)

school children doing experiment with toy vehicle
During the formal operational stage, children learn to use logic and create theories.

In the formal operational stage, which is the final stage of cognitive development, a child learns more sophisticated rules of logic. They can use logical roles to understand abstract concepts and solve problems.

The child is now able to analyze their environment and make deductions. They move beyond the limits of understanding objects and facts, toward problem-solving. This involves creating theories about what is possible based on their existing knowledge.

The child can now use their existing knowledge to create new theories about the world and make predictions about what will happen in the future.

Important concepts

The following sections will explain several important aspects of cognitive development that Piaget proposes as a part of his theory.


Piaget was the first to include the idea of a schema into a theory of cognitive development. A schema is a category of knowledge, or a mental template, that a child puts together to understand the world. A schema is a product of the child’s experiences and can represent objects, events, or concepts.

For example, a child can develop the schema of a dog. At first, the word “dog” only refers to the first dog they meet, but over time, the word comes to represent all dogs. When a child is putting this schema together, they may call every furry, four-legged animal a dog before they master the category.

In addition to creating new schemas, children can adapt their existing schemas based on new experiences.

As a child ages, they form more schemas and adapt existing schemas to allow them a greater understanding of the world. In this sense, schemas are a way of structuring acquired knowledge.

Two key concepts related to schemas are assimilation and accommodation:

  • Assimilation is where a child uses a pre-existing schema to understand a new object or situation.
  • Accommodation is where a child adapts a pre-existing schema to fit a new experience or object. This process is more mentally challenging than assimilation.


Equilibration motivates a child to continue through the stages of cognitive development.

When a child experiences assimilation, their world view is inaccurate, and they are in a state of disequilibrium. This motivates the child to accommodate new information, to reach a state of equilibrium.

Challenges to the theory

Piaget made many significant contributions to how people think about child development with his theory. However, it is not without criticisms, such as:

  • There is inconsistent evidence for these four stages across different children.
  • Evidence suggests that children can perform certain cognitive tasks at a younger age than Piaget suggests is possible.
  • Piaget’s theory does not account for other influences on cognitive development, such as social and cultural influences.
  • Piaget does not specify which psychological processes drive these developmental changes.

How to use Piaget’s theory

toddlers playing together
Interaction with other children will help a child’s development.

Piaget’s theory centers on the idea that children, as little scientists, need to explore, interact with, and experiment in order to gain the information they need to understand their world.

Caregivers and educators can put Piaget’s theory into practice by providing plenty of opportunities for children to explore their environment. This includes letting them learn by trial and error and by experimenting with their environment.

In the early stages, people can help a child learn better by giving them new and interesting toys to play with and answering the questions they ask about the world. Providing challenging new objects and situations can create disequilibrium, which encourages the child to learn to reach equilibrium.

In later stages, word puzzles, problem-solving tasks, and logic puzzles will help their cognitive development.

Allowing a child to interact with other children may also help enhance their learning, especially those of a similar or slightly higher developmental stage to their own.


Piaget’s theory of cognitive development had a significant impact on how people understand childhood development today. Piaget suggests that children go through four distinct stages of cognitive development from birth to adulthood.

Each stage includes certain milestones where the child demonstrates a more sophisticated understanding of the world. Piaget believes that development occurs through a continuous drive to expand and adapt schemas, or understandings about the world. However, some people have criticized Piaget’s theory.

People can also explore other theories of cognitive development, such as Vygotsky and Montessori theories.

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