“I find myself opposed to the view of knowledge as a passive copy of reality. – Jean Piaget

How do we learn things? The answers to this age-old question have been examined and analyzed by many scientists. There are plenty of prominent theories explaining cognitive development and helping us to understand the foundation of knowledge.

One of the most prominent answers to the question has come from a Swiss psychologist, Jean Piget. What is Piaget’s theory of cognitive development? Let’s examine the theory and its core concepts, before analyzing its applications and the critique the theory has received.


Let’s start by introducing Jean Piaget, the theory’s founding father, together with the core idea of his theory.

Who was Jean Piaget?

Jean Piaget was a psychologist, who became famous for creating his scientific theory about the intellectual development of children. He was born in Switzerland in 1896, showing an interest towards nature and science from an early age. When he was just 10 years old, he published a scientific paper about albino sparrow in a naturalist magazine. Piaget gained his Ph.D. in natural history at the age of 22 at the University of Neuchatel, after which he gained formal training in psychology.

Piaget spent some time studying with Carl Jung and during this time, he met with Theodore Simon, who had been a collaborating with Alfred Binet. Simon offered Piaget a role, which led to Piaget developing an interest in the cognitive development of children. The role saw him supervise the standardization of an intelligence test developed by Binet and Simon. While working, Piaget observed children and concluded that children are not less intelligent than adults, but the difference is how they think and view things.

Piaget’s interest in cognitive development of children was further increased by his nephew Gerard, and specifically how he played around with toys in ways that seemed irrational to adults. When Piaget had his daughter Jacqueline, he paid specific interest in her early development. These observations reinforced his idea that children’s minds aren’t just miniature adult brains, but that development and intelligence are gained in stages. He believed strongly that education is the greatest strengths of humankind and said

only education is capable of saving our societies from possible collapse, whether violent, or gradual”.

Piaget was one of the first psychologists to construct a systematic understanding of cognitive development – how do we learn? How do we gain intelligence? He contributed to a number of fields, including children’s cognitive development but also genetic epistemology. In 1955, Piaget founded the International Center for Genetic Epistemology in Geneva. He worked on the faculty of the University of Geneva and as the director of the Center until his death in 1980.

The essence of Piaget’s theory

Albert Einstein once called Piaget’s discoveries of cognitive development as, “so simply only a genius could have thought of it”. As the above shows, Piaget’s theory was born out of observations of children, especially as they were conducting play. When he was analyzing the results of the intelligence test, he noticed that young children provide qualitatively different answers to older children.

This suggested to him younger children are not dumber, since this would be a quantitative position – an older child is smarter with more experience. Instead, the children simply answered differently because they thought of things differently. Similarly, when Piaget observed his nephew Gerard playing with a ball, he noticed something that to adults seems irrational. When the ball rolled out of sight under a sofa, Gerard began looking at it from the spot he last saw the ball, not under the sofa. These observations reinforced his idea that young children and older children have qualitative and quantitative differences in thinking.

At the heart of Piaget’s theory is the idea that children are born with a basic mental structure, which provides the structure for future learning and knowledge. He saw development as a progressive reorganisation of these mental processes. This came about due to biological maturation, as well as environmental experience.

We are essentially constructing a world around us in which we try to align things that we already know and what we suddenly discover. Through the process, a child develops knowledge and intelligence, which helps him or her to reason and think independently. Instead of there being a gradual increase in the complexity of behavior and ideas, development is marked by qualitative differences. We simply don’t yet have a proper alignment of things we know with things we discover. Therefore, Piaget’s theory has two core aspects to it:

  • We first construct our image of the world – coming to know something.
  • We then go through stages of implementing the knowledge with what the world around us is telling – discovering the discrepancies.

The below clip is a great illustration of Piaget’s theory in a nutshell:


The theory is built around three core components: schemas, equilibrium, assimilation and accommodation, and the different stages of development.


A schema is a description of both the mental and physical actions required in understanding and knowing. It’s a category of knowledge used in interpreting and understanding the world – the building blocks of knowledge. Without them, you would find the world incomprehensible. The world with its things wouldn’t mean anything.

But schemas provide you a way to organize your knowledge, creating units of objects, actions and abstract concepts. According to Piaget’s own definition of schema, from his 1952 book The origins of intelligence in children, they are,

a cohesive, repeatable action sequence possessing component actions that are tightly interconnected and governed by a core meaning”.

You have many schemas about a variety of things. An example could be your schema about potatoes – what do you know about them? Your knowledge might be based on your experiences; they taste good when baked, they have an outer layer and they are grown underground. Your schema is essentially the knowledge you have (they grow under the ground) and your experiences of the object/idea (they taste good when baked). Therefore, a schema will change over time.

A schema is a cognitive structure that represents knowledge about everything that we know about the world, including oneself, others, events, etc.
A schema is important because it allows us to quickly make sense of a person, situation, event, or a place on the basis of limited information.
So, when a schema is activated, it “fills in” missing details

Source: SlidePlayer presentation by Kazuyo Nakabayashi

Piaget thought schemas to have this ability to change as people process more experiences. According to his theory, a child would modify, add or change the existing schemas as new information or experiences occur. So, if the child would one day eat a disgusting potato, he or she would add to the existing schema. Potatoes wouldn’t be just tasty, but could have the occasional foul taste to them.

Piaget’s ideas of schemas were driven by his background in biology. He saw the schemas as mental organizations controlling behavior or adaptation to the environment. Furthermore, as you gain maturity, the schemas become more complex. For instance, your schema about potatoes becomes much wider; perhaps you gain more information about the different varieties, you understand how different potatoes taste different and so on.

Piaget suggested that the schemas eventually become organized in a hierarchical order, from a general schema to a specific schema. An infant has a schema, such as the sucking reflex. When something touches the baby’s lips, they start sucking. On the other hand, as you grow older these schemas become less genetic and more about our surroundings. You don’t go to a restaurant, pay the bill, eat the food, and then order. You do it all in reverse order and this is an example of a complex schema.

Equilibrium, assimilation and accommodation

The second fundamental concept is the compilation of three concepts: equilibrium, assimilation and accommodation. Out of these three, assimilation and accommodation are the two core processes people use in order to adapt to the environment – the attempt to make sense of new information and to use it for future.

On the other hand, equilibrium is the attempt to strike a balance between the schemas in your head and then what the environment is telling.


When you take in new information regarding your existing schema, you are assimilating. When you encounter French fries and identify it as potato, you are assimilating the French fries into your pre-existing schema. You are essentially using a pre-existing schema to deal with a new experience, situation, object or idea. You take the French fries and assimilate them inside a schema, instead of creating a new one. The process of assimilation is a subjective occurrence, since we are always modifying experiences and information in a way that fits our pre-existing beliefs.

Children’s assimilation can, therefore, seem silly on the onset. R.S Siegler et al. gave an example of a child with a pre-existing schema of clowns in their 2003 book How Children Develop. A young child might have an image of a clown and according to his or her schema, clowns have shaved heads and lots of frizzy hair on the sides. When the child encounters a man with the haircut (even without clown costumes and the like), the child might point to him and say “clown”.


Assimilation is the first attempt of understanding new information and experiences, with accommodation adding another solution if the above is insufficient. In accommodation, you try to modify your existing schemas and ideas, with the process giving you a new experience or knowledge and often resulting in the birth of new schemas. For example, you might see French fries, but after biting into them realise they are made from sweet potato. You therefore, accommodate your existing schema (not everything that looks like French fries is potato) and add or create a new schema (you can use sweet potato to make French fries). You are changing the existing structures or the knowledge you have to fit the environment around you.

Generally, accommodation is a result of a failure of the schema. The existing knowledge you have simply doesn’t work in the situation you are in – the French fries just don’t taste like potato, no matter how hard you try. Therefore, to overcome this obstacle, you change, add and modify your strategy or schema. If you think about the example of the child and the clown, the child’s parent might explain how the man is not a clown, but that the hairstyle was just something he has and it isn’t there for laughs. Now the child would need to change the schema of clown to include other things (making people laugh, red nose, funny costume) in order for it to work.


Finally, you have the idea of equilibrium, which Piaget believed to be the child’s attempt to strike a balance between the two mechanisms: assimilation and accommodation. Piaget believed it to be the mechanism children use in order to move from one stage of thought to the other.

The process involves the child applying previous knowledge (assimilation) and changing the behaviour if the knowledge is not aligned with the new knowledge (accommodation). The process is beautifully illustrated in the below image:

Source: Based on SlidePlayer presentation

Cognitive development is not a steady process according to Piaget’s theory. Instead of knowledge being something we gain at a steady rate, we tend to develop in leaps and bounds. Therefore, equilibrium occurs in different ways and is the key process children, specifically, use to move beyond simply assimilating things. You could think of equilibrium as a sort of balance restoring process.

When you encounter the odd taste of the sweet potato fries, you don’t just go frustrated and wonder what is happening, but you restore balance by accommodating your existing schemas. Next time you encounter a French fry that looks like it’s from sweet potato, you won’t assume it’s potato anymore. If the taste doesn’t match to sweet potato, you again try to accommodate – perhaps it was carrots!

The stages of development

The final core concept of Piaget’s theory is perhaps the most important: the stages of development. As I mentioned above, Piaget thought cognitive development as a process or construction of a mental model of the world. Development is biological and as the child matures, changes occur in cognitive understanding. According to Piaget, there are four universal stages of cognitive development:

  • Sensorimotor stage – The core idea for the sensorimotor stage is object permanence. This requires the formation of a schema of the object and the knowledge the object continues to exist even after it is out of view. According to Piaget, the stage allows people to learn objects are distinct entities, with an existence out of the individual’s perception. The ball will still be a ball even when it rolls under the sofa.
  • Pre-operational stage – Thinking begins moving towards symbolical stages during the pre-operational period. You learn that words and objects can be something other than themselves. Children start to develop imagination and things can start having more meaning. You might remember having a ball as a best friend or you made a toy plane out of cardboard. Nonetheless, the pre-operational stage is still controlled by egocentric thoughts. This means you would find it difficult to see another person’s viewpoint and illogical thinking can still occur. For example, if you split water into two jugs, one wider and the other taller, the child might think the taller one has more water inside it.
  • Concrete operational stage – Things start heating up during the concrete operational stage. According to Piaget’s theory, this is when the child starts showcasing logical or operational thought. Instead of having to physically try things (such as pouring the water back him- or herself), the child begins to think things through internally. While the developmental stage sees more logic in thinking, the thought patterns continue to be rigid. Another important aspect is the diminishing of egocentric thinking. Children begin to understand their thoughts, feelings and ideas are unique and other’s might think and feel differently.
  • Formal operational stage – The final stage for Piaget was about the ability to increase logical thinking, using deductive reasoning and understanding abstract ideas. You don’t just think there’s one solution to problems, but you start using abstract ideas and different hypotheses to go about your life. The operational stage doesn’t really end, as we continue to gain new knowledge and experience long into adulthood.

Piaget never assigned any specific years to each stage, although there have later been an attempt to indicate an average age at which the child might reach each stage. More importantly than that, Piaget did believe the stages to be experienced in the same order by everyone and you can’t miss a stage under normal development.


Piaget’s theory is one of the most influential cognitive development theories out there. Despite being conducted and challenged (as I’ll explain in the next section), the findings have been used in a number of different contexts. Based on Piaget’s observations, the ideas have been applied in classrooms, dealing with young children. But the ideas and concept at play can also tell a lot about training and development in more general.

You should keep in mind that Piaget didn’t ever relate his theory to education, but other psychologists and researchers have applied his ideas to educating and training children. The theory was used as a basis for primary education practices in the UK, for example. Nonetheless, Piaget did have a few essential things to say about learning and development, which you should take note of.

First, Piaget based his ideas on biological maturation and stages, which means there is a concept of ‘readiness’ involved with development. He believed children to require a certain level of maturity before they can be taught a specific concept. Until the child is mature enough to think of other people’s feelings, it can be difficult to make them understand how other children might not find teddy bears cuddly.

Piaget also thought assimilation and accommodation to be active learning experiences. To him, problem solving is not a skill to be taught, but to be discovered. Therefore, children and other learners must be active participants of the training or education, not just passive participants. Therefore, many classrooms use active discovery learning as the basis, in which the teacher simply facilitates learning instead of directing. The child essentially gets to make his or her own experiments while learning.

If you want to draw certain application conclusions from Piaget’s theory, they could be the following:

  • Use props and other aids to support learning. Since development is an active experience, you want to engage the person learning. You should provide the opportunity to test things, feel things, and experiment with things in order to boost to engagement and ensure the child gets to test assimilation and possibly accommodating to the new information.
  • Combining actions with words. In the earlier stages, it is especially important to keep things simple and short. You want to give a presentation and an explanation at the same time. For example, if you are teaching how to build a paper plane, you should explain the building process while simultaneously showing how it’s done.
  • Understanding the different experiences people have. As well as teaching children about the importance of understanding other people’s experiences or feelings, you need to be conscious of this. People ascribe different meanings to words and the schemas might be different to everyone. When you encounter such a situation, you need to understand it rather than fight against it. Both you, as a teacher, and the person, as the student, might occasionally need to assimilate and accommodate your schemas.

When it comes to application of Piaget’s theory, it’s crucial to remember he didn’t think intellectual development is a quantitative process, i.e. you aren’t just adding more information to existing knowledge over time. Instead, development is about qualitative change, meaning that you gradually process more information and change your existing understanding accordingly.


While Piaget’s theory has caught a lot of attention and many educational institutions have used it, the concept has also attracted its fair share of criticism. What do researchers find most bothersome about the theory? One of the key critique is directed to the theory’s focus on development as stages.

While Piaget didn’t think these stages occur at a specific age, he nonetheless suggested you move from one stage to another. According to scientist who find this problematic are Lev Vygotsky and Bruner, who believed development to be a fully continuous process. Instead of moving from a single stage to another, they feel cognitive development is never ending process that doesn’t transform in its essence. The Russian psychologist, Vygotsky, also disagreed with Piaget’s notion that language is secondary to action. Piaget believed thoughts always precede language, while Vygotsky thought the origin of human reasoning to be rooted in our ability to communicate rather than interacting with the material world.

Furthermore, Piaget’s theory is criticized for its emphasis of biological maturation. The theory sees development as a genetic and biological process and therefore leaves out the impact of culture or social setting. Dasen shares in his essay in the book Psychology and Culture his observations amongst aboriginal children in Australia.

The children did similar spatial awareness and conservation tasks that Piaget conducted, with the aboriginal children having the ability to conserve later than Piaget’s Swiss children. On the other hand, the aboriginals had learned spatial awareness much earlier to Swiss children. According to Dasen, cognitive development is therefore not just a maturation process, but also dependent on cultural factors. In this instance, spatial awareness is crucial for nomadic groups to survive and live on a day-to-day basis.

Piaget’s theory was based largely on observation and clinical interviews. As I outlined at the beginning, he got interested in the topic as he observed children’s answers and playtime. But observation is more open to bias than anything else. My observations of a child playing with a ball might be very different to your observations.

This is especially true for his theory, as he constructed the whole theory on his observations alone. If he had discussed the findings with another researcher, the results might be found more reliable. For example, his interviews weren’t observed by another psychologist or observer – the answers might have been interpreted differently if someone else also looked at them.


The key takeaway from Piaget’s theory should be that learning and gaining intelligence is an active process, not passive. The theory believes development to be about continuous change and adaptation to the environment – you aren’t just obtaining information, but you are actively transforming your thoughts to fit the reality around you.

You use your obtained knowledge, the schemas, and implement new knowledge either through assimilation or accommodation. Essentially, the search for information is about finding equilibrium – balancing your existing knowledge with new. While Piaget’s theory has attracted criticism from other behavioral scientists, some of its core findings about learning and education are still being used in training facilities for young and for old.

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