Piaget’s Theory of Cognitive Development

One of the most well-known theories to explain a child’s development was created by Jean Piaget. On this page, we’re going to go over the basics of his theory on cognitive development.

If you have ever babysat, worked with children, or cared for younger siblings, you might have experienced moments where you noticed that the child just didn’t understand simple concepts. When you play peek-a-boo with a baby, it appears as though they genuinely don’t know where you went. When you try and reason with a toddler, it appears as though they can’t understand why their brother also needs to eat food, even though the toddler wants it for themselves.

Other than causing hilarious moments of misunderstanding, these situations show how far along the child is in their cognitive development. There are certain concepts and skills that children develop as they age into young adults.

piaget's stages of cognitive development

Who is Jean Piaget?

Jean Piaget was a Swiss psychologist who traveled to France to study children and intelligence. He noticed, while studying children and raising three children of his own, that children would get the same questions wrong or misunderstand similar concepts at the same age.

He went on to develop a theory that outlined different stages that children went through to complete their cognitive development.

There are four stages that Piaget believes children have to go through in order to reach full human intelligence. These four stages are the:

  • Sensorimotor Stage
  • ProOperational Stage
  • Concrete Operational Stage
  • Formal Operational Stage

If you want to remember the order of these four stages use this mnemonic device: “Some People Can’t Focus.”

Let’s go through each of these stages.

Sensorimotor Stage

This is the first stage in the theory of cognitive development. It starts at birth and continues until the age of 2. During this stage, babies use their senses to develop schemas, a concept I will explain later, and learn about the world around them. Piaget breaks the sensorimotor stage into six substages. The first substage is simply the refinement of basic reflexes that help the baby survive and feed. By the sixth substage, the baby has begun to experiment with different movements in order to get a reaction or experience sensations. They might hold a rattle, shake it, or throw it across the room in order to see what the consequences of those actions are.

object permanence in the sensorimotor stage

In this stage, the child develops object permanence. When children are first born, they cannot understand that items exist outside of what they can see and hear. As they start to develop, they understand that even though their mother has walked out of the room, the mother still exists.

Preoperational Stage

The second stage of cognitive development, the Preoperational Stage, lasts between the ages of 2-7. This is also known as “early childhood development.” While the child has already established that things exist outside of what they can see and hear, they are still limited to understanding things from their own perspective. This is called egocentrism. As the child moves through the Preoperational Stage, however, the child begins to use symbolic play and thought to move out of an egocentric way of thinking. They can begin to see things from other points of view. While Piaget theorized that this development happened around age 7, other psychologists have concluded that egocentrism ends around age 3-5.

Children also start to develop language at this time. They use symbols to connect letters and words with sounds. This is why children begin to read as early as 2.

Throughout the Preoperational Stage, children also learn how to combine different schema to solve a problem and understand the world around them. In the beginning stages of the Preoperational Stage, children have a hard time understanding Conservation. They can’t comprehend, for example, that the same amount of liquid can be held in two containers with different shapes. They may say a tall, skinny glass can hold more liquid than a short, wide glass of the same volume.

Concrete Operational Stage

As the children hit age 6 or 7, they move into the Concrete Operational stage. They can begin to use logic to solve problems and come up with conclusions. Children are generally limited to inductive reasoning during this stage. For example, if they observe 10 dogs and all 10 dogs pant in the summertime, they can conclude that all dogs pant during the summertime.

Deductive reasoning comes later.

In the Concrete Operational Stage, children can begin to grasp the idea of Conservation. They also begin to understand Classification and Reversibility. Reversibility works well with Conservation. Children between the ages of 7-12 begin to understand that if you smash a ball of clay, it still has the same quantity as it did previously. With reversibility, the child begins to understand that smashing the ball of clay is reversible. They can simply roll the ball back up and it will still maintain the same quantity as before.

Classification is the ability to classify and organize objects. Through seriation, the children can also begin to classify and order those objects due to logic.

These skills greatly contribute to a child’s ability to understand the world around them and solve problems. But they are still limited and have one more stage in their cognitive development.

Stage 4: Formal Operational

The last and final stage in Piaget’s theory of cognitive development doesn’t end when a child reaches their teenage years or even adulthood. When the child reaches the age of 11 or 12, they enter into the Formal Operational Stage. This stage lasts for the rest of their lives.

The Formal Operational Stage is the time when the child begins to use abstract thinking and deductive reasoning to solve problems. They can think outside of the rules of the world and use more than just trial and error to approach problems.

Children also develop meta-cognition during this time. Not only can they start to use hypothetical situations to solve problems and solve more complex problems, they can also think about their thought processes.



So these are the four stages that Piaget describes in his Theory of Cognitive Development. As the child goes through each of these four stages, Piaget believes that they “collect” information as well as acquire that knowledge. These are called schemas. 

There are many types of schemas that people collect and change throughout their lifetime. They include:

  • Person schemas
  • Self-schemas
  • Event schemas
  • Social schemas

An example of a social schema may be the idea that you have to look someone in the eye when you are talking to them. (A person who grows up in a different culture may develop a different schema – that you must not look a person in the eye when you are talking to them.) Self-schemas include information about yourself, like the fact that you have two feet and two hands. As you develop, you may acquire additional schemas. The way you learn to solve problems and the knowledge of what a schema is in the first place are schema!

Assimilation and Accommodation

As I said earlier, we acquire new schema, but we also change those schema as we acquire new information and thought processes. These two processes are called assimilation and accommodation. 


Assimilation is the process of adjusting the schema you currently have in order to make room for new or even conflicting information. You also learn where and how to store the information that you currently have.

Technology is a great example of how we assimilate new information. You might have had your first exposure to a word processor when you played on a typewriter. You learned how to place your fingers on the keys and saw that pressing each letter created a letter on the page.

As technology evolved and you grew up, however, you were introduced to new schema, like Microsoft Word. You still put your fingers on the same keys and saw letters pop up onto the screen, but you also learned how to Save, Print, Copy, and Paste the letters that you typed.

Throughout the development of technology and your need to use a word processor, you become better and better and organizing the skills and information needed to complete your tasks. Your original schema about word processing was never proved to be “wrong,” but was merely expanded by new information.


Accommodation is the process of altering or changing the schema that already exist in order to accommodate new information. New schema may also be introduced during this process.

An example of this is how children learn about animals. When they see a gorilla, they might see a hairy primate and apply the schema of “gorilla.” But not all hairy primates are gorillas. As they assimilate new information, the child creates schemas for “baboon,” “chimpanzee,” and “orangutan.” New schema are created for these additional animals. The idea of what a gorilla was had to be changed and limited to what a gorilla actually is.

This process may also happen if children learned inaccurate information. Children who grow up with prejudiced parents, for example, may have to alter their schema of how the world works. If they grew up believing that one group of people were

Equilibration (balance of Assimilation and Accommodation)

Assimilation and accommodation are two key learning processes. You cannot expand your worldview without making room for new information and developing new schema. But which one is most important?

Piaget believed that an equal amount of both assimilation and accommodation were necessary to foster cognitive development. Children benefited most when they could make room for new information that didn’t change their existing schemas and could alter schemas with new, more factual information.

How Piaget’s Theory of Cognitive Development Affects Teaching and Interacting With Children

As you start to learn more about the different stages of cognitive development, you can start to use activities to foster a child’s development. You can encourage pretend play to develop a child’s understanding of symbols. You can give them logic puzzles to help them refine their skills during the Concrete Operational Stage.

Continue learning about each stage of cognitive development. As you do, you will learn more about when children begin to acquire different skills. Use this information to help your students or the children in your life as they go through each of the four stages.

Practical Psychology

Practical Psychology began as a collection of study material for psychology students in 2016, created by a student in the field. It has since evolved into an online blog and YouTube channel providing mental health advice, tools, and academic support to individuals from all backgrounds. With over 2 million YouTube subscribers, over 500 articles, and an annual reach of almost 12 million students, it has become one of the most popular sources of psychological information.

Leave a Comment