Piaget’s Stages of Cognitive Development

Piaget's stages
(Last Updated On: January 17, 2019)

Piaget’s stages of cognitive development describes a series of stages of mental development that progresses over the course of childhood. This theory had a tremendous impact on the fields of developmental psychology and education. The theory outlines four distinct stages and focuses on how children acquire knowledge as they grow.

An Overview of Piaget’s Stages

Piaget’s stages of development are:

  • The Sensorimotor Stage (ages 0 to 2)
  • The Preoperational Stage (ages 2 to 7)
  • The Concrete Operational Stage (ages 7 to 11)
  • The Formal Operational Stage (ages 11 into adulthood)

The theory was the work of a man named Jean Piaget, a Swiss psychologist who became the first to conduct systematic research on the cognitive development of children.

What made Piaget’s stages so unique and revolutionary?

  • Piaget was one of the first to suggest that the way children think is fundamentally different than that of adults. Prior to Piaget, the prevailing belief was that children were simply smaller versions of adults and that their thinking was simply less competent than that of adults. Piaget’s work demonstrated that children think about the world differently than adults do.
  • Piaget’s stages suggest that kids actively participate and construct their knowledge. Rather than believing that children passively take in the things they observed, Piaget believed that kids play an active role in learning about the world around them.
  • Each of Piaget’s stages is marked by distinctive shifts in the way that kids think. The theory he developed describes four different stages of cognitive development that children go through as they learn more about the world.
  • During the earliest stages of development, children learn about the world primarily through their senses. As development progresses, children’s intellectual abilities become increasingly sophisticated, eventually allowing kids to think and reason about abstract concepts and problems.

How Did Piaget Form His Theory?

Piaget’s fascination with science began early in life, with his initial interests lying with the natural sciences. Born in the late 1800s, Piaget was a child prodigy. He published his first scientific paper on the subject of mollusks when he was just 11 years old. He went on to earn a Ph.D. in Zoology. It was after spending a semester studying with Carl Jung that Piaget developed a stronger interest in psychology.

It was his work in Alfred Binet’s laboratory in Paris that Piaget developed an interest in children’s cognitive development. Charged with interpreting the results on the standardized intelligence tests that Binet had developed for the French government, Piaget was interested in why children answered questions incorrectly. Upon questioning kids about their answers, he realized that how they responded depended upon their level of intellectual development.

His observations of his young nephew and later his own children added to his growing theory of childhood cognitive development.

Piaget’s theory focused on three critical components:

  • Schemas, or the mental frameworks that make up knowledge
  • The ways that this knowledge is acquired or altered (assimilation, equilibration, and accommodation)
  • The stages of mental development that children go through as they obtain and create knowledge.

Piaget’s Stages of Cognitive Development

Piaget proposed that children progress through four distinct stages of intellectual development. Each stage is marked by changes in how kids think about and relate to the people and object in their environment.

1. The Sensorimotor Stage (ages 0-2)

  • Children learn about the world via their senses
  • Basic activities such as sucking, rooting, listening, grasping objects, and sucking on things are how infants learn about the world
  • As they progress through this stage, they eventually learn object permanence, or that things continue to exist even when they can no longer be seen

During the first two years of life, a child’s knowledge of the world stems from motor actions and sensory information. A remarkable amount of learning takes place during this relatively brief period. One of the critical events of the sensorimotor stage is the development of object permanence, or the understanding that objects continue to exist even when they cannot be seen.

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The physical milestones of this stage also contribute to cognitive development, as children explore the world through reaching, grasping, rolling, crawling, and eventually walking. The earliest foundations of language development are established during this stage as well.

What Is the Sensorimotor Stage?

During the sensorimotor stage, infants learn about the world around them through their senses, perceptions, and motor skills. Infants are limited in terms of their ability to independently explore, so every interaction they have with people and the environment serves as an important learning opportunity.

Babies and toddler rely on the basic abilities they were born with, such as rooting, sucking, chewing, and looking, to learn more about themselves, the people around them, and the environment they live in.

Looking at a very young child, you might question just how much they really are able to generate knowledge from their actions. The truth is that babies are able to acquire a tremendous amount of information just by utilizing their sensory systems and motor skills. Sights, sounds, movements, tastes, smells, and textures all provide valuable information that help infants discover the world.

6 Sensorimotor Substages

Piaget believed that the events of this stage were so dramatic that he actually divided the sensorimotor stage further into six distinct substages.

1. Reflexive Activities (0 to 1 month): At this substage, the infant gains knowledge of the world through their inborn reflexes. At this point, an infant’s actions pretty much consist of performing reflexive actions such as sucking at a nipple or chewing on a toy.

Through these actions, new objects are assimilated and reflexes are accommodated to respond to new objects. While these actions seem very basic, they serve as an important stepping stone in intellectual development.

2. Primary Circular Reactions (1 to 4 months): Infants begin to repeat reflexive actions that are related to their own bodies and that they find pleasurable. For example, a baby might suck her thumb or kick her legs against a soft blanket. Babies also begin to notice when objects disappear.

3. Secondary Circular Reactions (4 to 8 months): Babies continue to repeat actions that they find enjoyable, but they also begin to perform actions that involve manipulating objects. For example, a baby might shake a toy in order to hear the sound that it makes.

4. Coordination of Reactions (8 to 12 months): During this stage infant begin to perform more goal-directed actions. Rather than simply repeating pleasurable actions, they will intentionally seek out actions or objects in the environment that they want to play with. For example, a child might push aside unwanted object to get to an interesting toy.

5. Tertiary Circular Reactions (12 to 18 months): During this substage, infants begin to experiment with new ways of solving problems. Babies now display intentional reactions that they have learned during the earlier substages. For example, a child might take a stack of blocks apart and will now try to figure out how to put it back together again. Babies also explore trial-and-error processes in order to see what happens or what sort of reaction they will get.

6. Early Representational Thought (18 to 24 months): During this final sensorimotor stage, children begin to show signs of symbolic thought. Babies now possess mental representations of objects, which means they are also able to think about things that are not there.

Object Permanence During the Sensorimotor Stage

One of the hallmarks of the sensorimotor period in Piaget’s stages of development is the presence of egocentrism. Children at this stage of development are unable to take the perspective of other people.

In addition to not being able to see things from others people’s perspective, children at this stage are also in the process of developing object permanence, or the understanding that objects continue to exist even when they cannot be seen. During the early sub-stages of the sensorimotor stage, children lack any sense of object permanence. If an object cannot be seen, it simply no longer exists in their view.

As children progress through this stage, they begin to learn more about the objects around them and the fact that things can exist even though they may be hidden. During the first month of life, a baby may track an object with its eyes but ignore the objects sudden disappearance. From about 1 to 4 months, an infant will stare at the spot where an object vanished.

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It is during the age from around 4 to 8 months that children start to search for an object that is partially concealed, and from 8 to 12 months a clear understanding of object concepts begins to emerge.

If you have ever played peek-a-boo with an infant, you can see the development of object permanence in action. A very young infant might not search for a hidden object and will be very surprised when it pops out from a hidden spot. A child with an emerging sense of object permanence, on the other hand, will actively search for the hidden object.

Final Thoughts on the Sensorimotor Stage

The sensorimotor stage of development serves as an important building block for future cognitive growth. While children may be limited to learning through their senses and motor actions, this does not mean that this is an uneventful stage of development. A tremendous amount of growth takes place during the sensorimotor stage, laying the foundation for the upcoming preoperational stage of development.

 2. The Preoperational Stage (ages 2 to 7)

  • Egocentrism is a common characteristic of this stage, since children struggle to see things from other’s point of view
  • Children begin to think symbolically and are able to understand that symbols and words represent objects in the real world

The early part of this stage of cognitive development is marked by the emergence of language. Why is this an important part of Piaget’s stages? Because it suggests that children are capable of symbolic thought. Children utilize language to symbolically represent objects, people, and ideas.

While their thinking is becoming increasingly sophisticated, kids at this stage of cognitive development struggle with logic and mentally transforming information.

Piaget’s experiments demonstrated, for example, that kids in the preoperational stage have difficulty with conservation.  For example, kids are shown two glasses containing the same amount of liquid. The liquid is then poured into two different containers – a short, wide glass and a tall skinny glass. While they saw that the two amounts were equal, children in the preoperational stage will invariably select the tall skinny glass as containing more.

This period of cognitive development is also marked by an inability to take another person’s perspective, which Piaget referred to as egocentrism. In his own experiments, Piaget found that when children were asked to select an image depicting another person’s view of a scene, children would simply select their own view because they could not imagine the scene from the other individual’s perspective.

 3. The Concrete Operational Stage (ages 7 to 11)

  • Children begin to utilize logical and organized in their thinking, but they tend to think about things in very concrete terms
  • They struggle to think about abstract ideas or concepts
  • They learn conservation, or the idea that the total amount of something such as a glass of water remains the same even if it is divided into smaller parts

The concrete operational stage of cognitive development is marked by the emergence of logical thought. Kids become much more capable at applying logic, but they also tend to be very concrete, literal thinkers. At this point, they still struggle with abstract ideas and hypothetical situations.

In addition to thinking more logically, kids also become less egocentric and capable of conservation. At this stage of cognitive development, children are better able to consider other people’s perspectives and understand that other people do not see things the same way that they do.

 4. The Formal Operational Stage (age 11 to adulthood)

  • Children at this stage of cognitive development are beginning to utilize abstract thinking when they consider problems
  • As they consider complex problems about the world, including social and moral issues, they become better at considering theoretical and abstract ideas

The fourth and final stage in Piaget’s stages of cognitive development is characterized by the emergence of abstract thought. Instead of simply relying on their own experiences, kids begin to imagine multiple possible ways of solving problems.

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Whereas younger kids typically rely on trial-and-error when solving problems, those who have reached the formal operational stage are able to systematically solve problems using logic. Trial-and-error may still come in to play, but it involves a more methodical and organized approach rather than the haphazard style that younger kids use.

While Piaget himself did not identify exact ages when these stages occur, most explanations of the theory identify a typical range during which the stage often occurs. While Piaget believed that these stages were universal, not all individuals reach the later stages. Not everyone, for example, reaches formal operations and becomes skilled at deductive reasoning and abstract thinking.

A Summary Chart of Piaget’s Stages

Stage of DevelopmentAgeCharacteristics of the StageDevelopmental Changes
Sensorimotor StageBirth to 2 YearsAt this stage of cognitive development, an infants understanding of the world comes from their sensory experiences and motor movements.Babies develop object permanence, or the understanding that things continue to exist even when they are out of sight.


Infants discover that they are separate entities from the people and things around them.

Through their interactions with people and objects, babies learn that their own movements can cause things to happen.

Preoperational Stage2 to 7 YearsDuring this stage, kids develop the ability to think symbolically. They utilize language and pictures to represent objects and ideas. However, they tend to be very egocentric and only see things from their own perspective.Egocentrism is high during this stage.


Children learn to think symbolically, but they also tend to be very concrete thinkers.

Concrete Operational Stage7 to 11 YearsWhile kids at this stage are still concrete thinkers, they become more logical at this stage of cognitive development.During this stage, kids learn to understand conservation, or the idea that two things can be equal amounts even though the size and shape of the object differs.


Concrete thinking tends to remain high, but kids become more organized and logical in their thoughts.

The use of inductive logic, or the ability to reason from a specific piece of information to a more general principle, emerges.

Formal Operational Stage12 and UpTweens and teens develop the ability to think abstractly and can solve hypothetical problems.This period is marked by the emergence of abstract thought.


As kids enter the teen years, they spend more time thinking about hypothetical situations related to moral and philosophical questions.

Deductive logic also emerges at this stage, which involves the ability to reason from a general principle to a specific situation.

The Impact of Piaget’s Stages

Piaget’s theory of cognitive development had a lasting impact on the fields of psychology and education. Most educational programs today are based around the idea that instruction should be geared towards a child’s developmental level. Strategies such as peer-led instruction and social facilitation are also rooted in the tenets of Piaget’s stages.

While influential, Piaget’s theory has not been without criticism. Many note that development does not necessarily align to a series of distinct stages, a fact that even Piaget himself observed. Others suggest that his stages may have been too broad, vague, and not clear on how children’s learning actually occurs.

Researchers also suggest that Piaget underestimated children’s abilities. The understanding of object permanence, for example, is thought to occur much earlier than what Piaget believed.

Nevertheless, Piaget’s theory of cognitive development had a powerful impact on our understanding of the intellectual abilities and growth of children.


Phillips, J.L. (1975). The Origins of Intellect: Piaget’s Theory. San Francisco: W.H. Freeman and Company.

Piaget, J. (1977). Gruber, H.E.; Voneche, J.J. eds. The Essential Piaget. New York: Basic Books.

Piaget, J. (1983). Piaget’s theory. In P. Mussen (ed). Handbook of Child Psychology. 4th edition. Vol. 1. New York: Wiley.

Schaffer, D.R. & Kipp, K. (2010). Developmental Psychology: Childhood & Adolescence. Belmont, CA: Cengage Learning.

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