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Sensory-motor period

ss psychologist) developed a defining theory about child development, which proposes that children progress through a series of four critical stages for their cognitive development .

In this period, according to Piaget ,  the individual knows through the senses and movement , that is, through perceptions and actions on the world. The four stages of cognitive development proposed by Piaget included: the sensory-motor stage (from birth to two years); the preoperational stage (from two to seven years old); the operative stage  (from seven to eleven years old) and the formal operative stage (from adolescence to adulthood).

The stage that we will detail below is the first phase of cognitive development, the sensory-motor stage.

Sensory-motor stage

During this stage, babies begin to know the world around them and gain knowledge through their senses and motor movements. The baby’s knowledge of the world is limited to his sensory perceptions and his motor activities.

It is a phase in which a cataract of senses and emotions occurs. It is all new for the baby, his senses do not stop being active while he is in a waking state, and when he sleeps he processes all the acquired information.

The sensory-motor stage is subdivided into six sub-periods:

  1. Reflexes : from or to 1 month
  2. Primary circular reactions : 1 to 4 months
  3. Secondary circular reactions : 4 to 9 months
  4. Coordination of secondary schemes : from 9 months to 1 year
  5. Tertiary circular reactions : 1 to 1 and a half years
  6. Invention : 1 1/2 to 2 years


Reflex is an involuntary reaction that occurs automatically. In this phase, it is based on reflexes , suction and grasp, basically because it is the only biological and organic structure that the baby has as a support. It is a neurological basis that allows you to react to certain stimuli in a certain way. 

A baby can show these reflexes while continuing to grow, mainly during the first six weeks of life.

Primary circular reactions

This reflex scheme begins to repeat itself; the baby  who at first sucks the mother’s breast, now sucks all the objects as well . He gets to know the world through objects and since this reflex action is repeated, it becomes more complex and becomes a habit . In other words, the actuation and suction is repeated mechanically and becomes a primary circular element . Babies begin to associate the back and forth movement of their hand towards their mouth or face, and they begin to realize that they have the ability to repeat the movement.

It is a period of symbiosis and adualism with his mother -or whoever fulfills that function-, therefore there would still be no   intelligence .

Secondary circular reactions

This sub-stage usually occurs when the baby reaches around four months of age and can continue until eight months of age. In it, a take-off occurs in terms of possibilities because the vision-grasp coordination leads him to take an object , since as this coordination does not exist, he could not direct the action to the objects. The actions have to do with chance, there is no intentionality or discrimination between means and ends , -although there is an outline of intentionality-.

Coordination of secondary schemes

There is the coordination of the sequential schemes because it is going to apply what it already knows and it is going to repeat it and in that repetition it is consolidating it in the assimilation schemes , allowing it a greater adaptation to the environment that it already knows. The intention to reach a certain object begins to be built. Piaget places the threshold of intelligence here, since the child already differs from the world.

Tertiary circular reactions

These reactions differ from circular secondary reactions in that they are intentional adaptations to specific situations. The baby is capable of creating new media through experimentation and exploration of the reality that circulates, managing through trial and error. The action falls on the medium , but active exploration and direct action are added to it. It is related to the object of knowledge and at the same time it relates the objects to each other .


There is a  revolution , everything that was assimilated and was suddenly still is used. There is intentionality and when he achieves what he wanted he is surprised, a real mental operation occurs. There is no affectivity unity to thoughtThe achievement of this stage is the notion of permanent object , that is to say, knowing that objects exist regardless of whether the child sees them or not; which also allows him to achieve the notion of time, space, causality, in the sense that a certain effect will produce certain consequences.

The times are limited, immediate but the field of action is broadened, although the process is not yet understood, but what happens at the beginning and at the end of each action is addressed. These achievements are categories of action, that is why we cannot yet speak of a thought linked to any representation. The child does not think, he simply acts, but there is intentionality and at the end of this period he achieves the representation as it is, also building an invariant, the instruments .

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Hello Readers, I am Nikki Bella a Psychology student. I have always been concerned about human behavior and the mental processes that lead us to act and think the way we do. My collaboration as an editor in the psychology area of ​​Well Being Pole has allowed me to investigate further and expand my knowledge in the field of mental health; I have also acquired great knowledge about physical health and well-being, two fundamental bases that are directly related and are part of all mental health.

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