Piaget’s stages of development is a theory about how children learn as they grow up. It includes four distinct stages, each with different milestones and skills.

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Jean Piaget was a renowned psychologist and cognitive theorist in the 20th century who focused on child development. His theories came from observing children and recording their development.

He brought attention to the idea that children are not just small adults, and he argued that the way they think is fundamentally different.

Piaget believed that children act as “little scientists,” exploring their environment to gain understanding. He thought that children do this naturally, without any adult intervention. He put forth the idea of distinct developmental stages through which children learn language, memory, and reasoning.

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

The following table outlines Piaget’s four stages of cognitive development:

StageAgeWhat happens
sensorimotor stage0–2 yearsBabies start to build an understanding of the world through their senses by touching, grasping, watching, and listening.

They also begin to develop a sense of object permanence, which means they understand that objects exist even when they cannot see them.
preoperational stage2–7 yearsChildren develop language and abstract thought. This means they can think about concepts and ideas that are not physical.

They also begin symbolic play (“playing pretend”), drawing pictures, and talking about things that happened in the past.
concrete operational stage7–11 yearsChildren learn logical, concrete (physical) rules about objects, such as height, weight, and volume. They also learn that an object’s properties stay the same, even if the appearance changes (e.g., modeling clay).
formal operational stage12+ yearsAdolescents learn logical rules to understand abstract concepts and solve problems. For example, they may understand the concept of justice.

Babies from birth to 2 years of age use their senses and bodily movements to understand the world around them, which is why this stage is known as the sensorimotor stage.

A newborn’s first method of communication is through basic reflex actions such as sucking, flailing their arms, or shaking their head. They use their five senses of sight, touch, smell, taste, and hearing to explore their surroundings and their body.

Infants gather information about these experiences, learning how different things make them feel. They also learn to tell the difference between people, objects, textures, and sights.

During this stage, children also start to understand the concept of cause and effect. They begin to remember that certain actions will have a specific outcome and use this to plan their actions in advance.

At around 6 months, they will begin to understand object permanence. This means the child knows that objects continue to exist even if they can no longer see, hear, or feel them.

When a child has object permanence, it means they can now form a mental image, or representation, of an object instead of only reacting to experiences in their immediate environment.

Examples

Certain behaviors can indicate that a child has developed some of the key skills from this stage. For example, a child who understands cause and effect may intentionally shake a rattle to make a noise or cry in order to gain attention.

A child who understands object permanence will:

  • know their caregiver is still there when playing games such as Peek-A-Boo
  • know a toy still exists even if it is hidden under a blanket
  • understand they or their surroundings are still there even if they cover their eyes

During this stage, children build on object permanence and continue to develop abstract mental processes. This means they can think about things beyond the physical world, such as things that happened in the past.

They also imagine and think symbolically, and they begin to display this ability through their language and behavior.

The five key behaviors children display during this period are:

  • Imitation: Children can now mimic another person’s actions, even if the individual they are modeling is no longer in front of them.
  • Symbolic play: Children begin assigning characteristics or symbols to objects. They can project the properties of one object onto another. For example, they may pretend a stick is a sword.
  • Drawing: Imitation and symbolic play are both essential elements of drawing. It begins as meaningless scribbles and progresses to more accurate representations of objects and people.
  • Mental imagery: Children start to visualize a wide range of things in their mind. They may ask the names of objects frequently to establish associations between words and objects.
  • Verbal evocation of events: This means children can use words to describe and represent past events, people, or items.

The primary function of speech at this age is to externalize thinking, rather than for communication. Children may talk in a stream of consciousness and develop more sophisticated language skills as they move through this stage.

Piaget believed that children remain egocentric throughout the preoperational stage. This means they cannot understand that other people think in different ways to them or that events that take place are not always related to them.

Examples

Some examples a child is at the preoperational stage include:

  • imitating the way someone talks or moves even when they are not in the room
  • drawing people and objects from their own life but understanding they are only representations
  • pretending a stick is a sword or that a broom is a horse during play
  • imagining that they are a superhero or someone they admire
  • inventing an imaginary friend

Piaget theorized that at this stage, children further develop and master abstract thought and become less egocentric. They can now understand that events do not always relate to them and that others have different points of view.

Children also become able to apply logical, concrete rules to physical objects. However, they cannot yet do the same thing for abstract concepts.

The concrete operational phase centers around three elements:

  • Conservation and reversibility: Conservation the understanding that objects can change in size, volume, or appearance but essentially remain the same. Reversibility means that some things that have changed can return to their original state, while others cannot.
  • Classification: This means children can classify objects into groups and subgroups. For example, they can group objects based on color, shape, or similarities.
  • Seriation: Seriation is a child’s ability to group objects based on height, weight, or importance. It is an essential concept to master, as children require this skill during math and science education.

Examples

Some signs a child has learned the skills from this stage include:

  • knowing that water has the same properties (e.g., wetness) even when it is in different vessels or has a different color
  • understanding that water can freeze and then melt again but that other changes are permanent
  • being able to organize crayons into groups based on their color
  • being able to sort their toys into order, based on their size or importance

In this final stage of cognitive development, children learn more sophisticated rules of logic. They then use these rules to understand how abstract concepts work and to solve problems.

The child can analyze their environment and make deductions. They can create theories about what is possible and what might happen in the future, based on their existing knowledge.

This is known as hypothetical-deductive reasoning. It is an essential part of the formal operational stage. It allows someone to consider “What if?” A person with this skill can imagine multiple solutions and potential outcomes in a given situation.

Examples

A child at the formal operational stage can think of numerous ways of solving a single problem, then choose the best option based on how logical or successful it is likely to be.

For example, if a child has to create a model of the solar system using materials they have at home, there are a number of ways they could use them. Thinking of several possibilities and then using the one that is the most logical or effective shows they have hypothetical-deductive reasoning skills.

Children at this stage can also examine and evaluate their own thoughts and actions. For example, if they argue with a friend, they can consider how their opinions or behavior might have contributed. They can then decide how to approach the situation.

The following sections explain several important aspects of cognitive development that Piaget proposes in his theory.

Schema

Piaget included the idea of a schema into his theory of cognitive development.

A schema is a category of knowledge, or mental template, that a child develops to understand the world. It is a product of the child’s experiences.

For example, a child can develop a schema of a dog. Initially, the word “dog” only refers to the first dog they meet. However, over time, the word comes to represent and include all dogs. When a child puts this schema together, they may call every similar animal a dog before they master the category.

Schemas constantly grow and adapt as children gain new experiences, giving them the structure to acquire knowledge. Piaget suggested this occurs in two ways: assimilation and accommodation.

Assimilation means a child uses a preexisting schema to understand a new situation. For example, if they meet a new breed of dog, they may include it in their schema for “dog,” even if it looks different to dogs they have previously encountered.

Accommodation means a child adapts a pre-existing schema to fit a new experience or object. For example, if a child encounters a cat, they may add it to their schema for “dog” until someone explains that dogs and cats are different. They will then adapt their schema to this new information.

Equilibration

According to the theory, equilibration is what motivates children to continue through the stages of cognitive development.

When a child assimilates new knowledge, their worldview is inaccurate, so they are in a state of disequilibrium. This state motivates the child to accommodate new information and reach a state of equilibrium.

Piaget made many significant contributions to theories about child development, and many are still influential today. However, others have criticisms of his ideas.

Firstly, the way Piaget conducted his research would not meet the standard of research academics adhere to today. He tended to observe and interview small numbers of children in natural settings, rather than in study conditions. This meant that it was possible for the small sample size or the environment to create bias.

Additionally, he carried out his research in Western Europe and did not take into account the impact that different social and cultural practices might have on child development.

While some academics agree that there are developmental stages, they may not be as distinct or concrete as in Piaget’s theory.

Research has demonstrated that some skills develop earlier than he believed. For example, a 2021 article notes that egocentrism appears to resolve much earlier than Piaget believed, at 4 to 5 years of age rather than 7 to 11.

Piaget’s theory centers on the concept that children need to explore, interact, and experiment to gain information and understand their world. Based on this idea, educators and caregivers can help children learn by allowing them to:

  • use their senses to explore objects and sensations (e.g., through touch, taste, sight, smell, or hearing)
  • explore their physical surroundings themselves, within safe limits
  • learn by doing, even if they make mistakes
  • interact with other children who are at a similar stage of development or slightly higher
  • get answers to questions they have about the world
  • encounter new situations, objects, or challenges that create disequilibrium, as this encourages them to expand their knowledge

In later stages, word puzzles, problem-solving tasks, and logic puzzles help children’s cognitive development.

If a child is not exhibiting the behaviors or skills set out in Piaget’s theory at the exact ages he predicts, it is not necessarily cause for concern. However, parents and caregivers should speak with a pediatrician if they have any worries.

Piaget’s stages of development is a theory that children go through distinct stages from birth to adulthood, with each stage bringing new skills and milestones as they develop their knowledge of the world.

Piaget believed that children develop through a continuous drive to learn and adapt schemas, which are mental templates that help them understand things. His ideas still have a considerable impact on child psychology and approaches to education.

However, there are criticisms of Piaget’s theory, as well as alternative models of child cognitive development that also came from the 20th century, such as the ideas of Lev Vygotsky and Maria Montessori.