Jean Piaget and cognitive development

Jean Piaget was a Swiss psychologist who developed a theory of cognitive development that attempted to go beyond the simple measure of mental ability that is IQ and gain a deeper understanding of a child’s mental ability. During the 1930s, it was widely believed that children were simply worse thinkers than adults. However, through a series of ingenious tests, Piaget (1936) demonstrated that children think completely differently from adults and, moreover, their ability to reason compounds in such a way that one form of logic leads to improved versions of as the child develops. Piaget’s theory had four stages of cognitive development.


Sensorimotor – The sensorimotor stage lasts from birth to around two years of age. This is a stage of discovery for the child. The child begins to examine the relationships between actions and the consequences of those actions. For example, a child begins to learn that if he pushes a spoon to the edge of a table, he will fall off. A child also begins to develop a self-concept. The child learns that he is separate from the outside world and that the hand is part of himself but the spoon is not. In addition, the child learns that he is capable of performing actions and manipulating the environment around him. They become more object-oriented and can play with a rattle or a set of keys, for example, for their enjoyment. During this stage, the child learns Object Permanence, which is the understanding that when an object is out of sight, it does not cease to exist. Piaget tested this by placing objects under a cloth in front of the child. An 8-month-old will stop and lose interest almost immediately, but a 1-year-old will actively search for the object. At this point, the child understands that the object continues to exist and has a mental image of the object. This is the first sign that the child has developed short-term memory.

Preoperative – This stage lasts from 2 years to 7 years of age and is the stage during which children develop language. At this stage, children are able to think symbolically. For example, during play, you may see a child pretending that a stick is a sword or a gun. A child’s speech also demonstrates his ability to think symbolically. However, while a child’s mind can think symbolically, she has trouble thinking logically and cannot manipulate information in her mind. Piaget (1936) demonstrated this through Conservation Experiments. There were two types in there: conservation of mass and number.

Conservation of mass- This experiment may involve a child being given two glasses with the same amount of liquid in them. The experimenter then pours one of the glasses into a larger glass in front of the child without adding any liquid. The child will then be asked which one holds more liquid and at this stage he will reply that the larger container holds more even though nothing is added to it. Also, the same experiment can be performed with two balls of clay of the same size. The experimenter will roll one into a cylinder and the child will identify the cylindrical one as the largest.

Number Conservation – This experiment involves a child who is shown two rows of coins that contain the same amount. The child will identify them as equals. However, after the experimenter extends one of the lines, the child will identify that as the one with the most.

Operational Concrete – This stage lasts from 7 to 12 years. At this stage, the child masters conservation and becomes much less self-centered. The boy now uses some logic and abstract thinking, but only in realistic terms that apply to his own experience. They still find it difficult to understand higher abstract thought.

Formal Operations – This is the final stage and begins around the age of 12. During this stage, the child improves his ability to think symbolically. They begin to consider abstract ideas like morality or the future. The great leap in the educational curriculum at this stage demonstrates this increase in mental capacity.


Piaget (1952) developed the idea of ​​schemata based on children’s cognitive developments. Piaget (1952) defined schemas as “a cohesive, repeatable action sequence possessing component actions that are closely interconnected and governed by a central meaning.” In other words, it is a way of organizing knowledge into mental plans based on the child’s day-to-day experiences. For example, when a person goes to the movies, he engages in the behaviors of buying a ticket, popcorn, finding a seat, and enjoying the movie, and he follows this schema every time he goes to the movies.

He identified three types of schemas: behavioral schemas related to physical objects and experiences, symbolic schemas, used to represent abstract aspects of experience, and operational schemas, used for mental activities that use thoughts such as mathematics. Piaget believed that children’s schemas develop and become more advanced as the child grows older. Also, a child will take in new information from the environment and add this knowledge to their existing schemas. However, if the child finds something with the same characteristics as an existing schema, she must accommodate it by creating a new schema. For example, a child develops a schematic for a car but does not know the difference between a car and a truck, so he must create a new schematic to tell the difference. When a child’s existing schema is sufficient to describe her current experiences, she is said to be in equilibrium.


Some criticisms of Piaget’s Theory of Cognitive Development are:

  • Piaget may have underestimated the role of individual differences in children’s cognitive ability.

  • No controls were set during experimentation, so there is nothing to measure against

  • The age limits of staging theories may not be consistent with the cognitive ability of all children. Also, age groups can change due to the Flynn effect.


Piaget, J. (1936). Origins of intelligence in the child. London: Routledge & Kegan Paul.

Piaget, J. and Cook, M.T. (1952). The origins of intelligence in children. New York, NY: International University Press.

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