Cognitive development refers to the way individuals think, explore, and observe the things around them. It is the emergence of thinking and understanding ability. Jean Piaget is referred to as the father of cognitive development. He was a Swiss psychologist who observed the intellectual development of children during childhood. According to him,

“Cognitive development is a progressive reorganization of mental processes as a result of biological maturation and environmental experience.”

He studied the intellectual development of his three children.

Stages of Cognitive Development

According to Piaget, there are four stages of cognitive development which are as follows:

Sensorimotor Stage (Birth-2 years)

During this stage, the child starts interacting with the environment. The child starts developing motor senses such as sight, sound, touch, smell, and taste. They start understanding the world through these senses. They start differentiating between animate and inanimate objects. At the end of this stage, children develop symbolic thought and also achieve object permanence.

Preoperational Stage (2-6/7 years)

In this stage, the child begins to represent the world in a symbolic manner. The child begins to use language and symbols. The child becomes capable of more complex mental representations. The preoperational stage is divided into two stages:

Pre conceptual stage (2-4 years)

At this stage, there is the increased use of verbal representation. However, speech is egocentric.

Intuitive stage (4-7years)

In this stage, speech becomes less egocentric and more social. The child starts basing their knowledge upon what they think is true.

Concrete operational Stage (7-11/12years)

In this stage, the child starts learning rules such as conservation, decentration, and reversibility. Children start developing the ability to perform mental operations and start solving problems in their minds. However, their operations are limited to real events and tangible objects.

Formal operational Stage (12 years and adult)

During this stage, the thoughts start becoming increasingly abstract and flexible. They start thinking about the consequences of their actions and start developing problem-solving skills. They also develop deductive reasoning and inductive reasoning skills.

Taking Piaget’s cognitive development theory into consideration, practical learning situations must be adopted. The curriculum should be designed according to children’s developmental levels.

Irreversibility in Child Development

Irreversibility refers to the incapability of mentally reversing an operation. It refers to the cognitive inability to think in reversing order when objects and symbols are manipulated. A child assumes that one’s actions cannot be undone or reversed. For instance, if a 3-year-old child is playing with dough and forms a ball out of it, the child may believe that the ball can easily be flattened or returned to its original state.

Characteristics of Irreversibility

The characteristics of irreversibility are as follows:

  1. Irreversibility occurs in the stage of childhood where a child holds the false assumption that actions cannot be reversed.
  2. Irreversibility occurs in the preoperational stage of Piaget’s cognitive development theory.
  3. The concept of irreversibility in a child’s cognitive development involves the idea that nothing can be reversed or undone.
  4. In irreversibility, children fail to realise that some things can be changed and returned to their original state.
  5. Irreversibility is characterised by a child’s cognitive or mental inability to reverse logical operations or a sequence of events.
  6. In irreversibility, a child does not have the ability to understand that actions can go both ways.
  7. During irreversibility, a child is incapable of thinking in the reverse order.


Piaget believed that irreversibility and reversibility were two important cognitive changes that helped in differentiating between the various developmental stages.