Jean Piaget


The Stages of Cognitive Development

Piaget's four stages of development occur in infancy, preschool, childhood, and adolescence. Each stage is characterized by a general cognitive structure that affects all of the child's thinking. Each stage represents the child's understanding of reality during that period, and each but the last is an inadequate approximation of reality. Development from one stage to the next is dependent upon the child's understanding of the environment in that particular stage. This phenomenon eventually causes such a degree of cognitive disequilibrium that thought structures require reorganizing.

Sensorimotor Development: Birth to 2 Years

According to Piaget, the most striking characteristics of children's behavior occur in the first 2 years of life.  The child's world is in the here and now, because it cannot yet be represented mentally.  In a very literal sense, objects only exist when the child can actually sense them and interact with them. When objects are not being sensed, then they cease to exist to the child. This shows the idea of object permanence; a realization of the permanence of objects.

The Sensorimotor stage is characterized by the child experiencing their world through movement and senses. During this stage, the children's thoughts are exceptionally egocentric, meaning they cannot percieve the world from anothers perspective or viewpoint other than their own.

The sensorimotor stage is divided into 6 substages:
1.Simple reflexes (Birth - 1 Month Old) Characterized by reflexes such as rooting and sucking
2. Primary circular reactions (1-4 Months Old) Infants learn to coordination sensations. A primary circular reaction is when the infant tries to reproduce an event that happened by accident (ex: sucking thumb)
3.Secondary circular reactions( 4-8 Months Old) Children become aware of things beyond their own body and become more object oriented. (ex: accidentally shaking a rattle and continuing to do so for the sake of satisfaction)
4. Coordination of secondary circular reactions(8-12 Months Old) Children start to show intentionality (ex: using a stick to reach something)
5.Tertiary circular reactions (12-18 Months Old) They start to explore new possibilities of objects
6.Internalization of schemes(18-24 Months Old) A shift to symbolic thinking

Preoperational Thinking: 2 to 7 Years


This stage brings a marked improvement in the child's increased understanding of the world from the sensorimotor stage. However, compared to an adults understanding the child's preoperational thinking still exhibits serious shortcomings.

The preoperational stage is divided into 2 substages:
1. Preconceptual thinking (2-4 years)
This substage is characterized by the child's inability to understand all the properties of classes. The child has acquired the ability to represent objects mentally and to identify them based on their membership in classes, however this child now reacts to all similar objects as if they were identical. This understanding is incomplete because they cannot yet distinguish between apparent identical members of the same class. 

Transductive reasoning is another feature of the child's thinking in the substage. Transductive reasoning is a faulty type of logic that involves making inferences from one specific to another. It can lead to correct or accurate conclusions, but it is not guaranteed to do so.

2. Intuitive thinking (4-7 years)
By this age children have formed a more complete understanding of concepts and have mostly stopped transductive reasoning. Their thinking has become more logical, although it is structured more about perception than logic.

Conservation is the term used to to refer to the realization that certain quantitative attributes of objects remain unchaged unless something is added to or taking away from them. This includes mass, number, area, and volume are all capable of being conserved.

Example: Children are shown two identical beakers filled to the same level with water. The experimenter then pours the contents of one beaker into a tall thing tube. Participants who had previously said the amount in each beaker were equal are now asked whether there is as much, more or less water in the new container. At the intuitive stage, they will almost always say that there is more because the water level is much higher in the tube. This shows that they are misled by the appearance as well as by lack of specific logical abilities.

Egocentrism is another type of thinking that is typical of the intuitive substage. Egocentrism is the inability to easily accept the point of view of other.

Concrete Operations: 7 to 11 Years

In this stage children begin to think logically but remain very concrete in their logic. This stage is centered around rules that now govern the child's logic and thinking - rules such as: reversibility, identity, and compensation.

The first, reversibility, emerges when the child realizes that an action could be reversed and certain consequences will follow from doing so.
is the idea that for every action or operation there is another operation that leaves it unchanged. For example, adding or taking away nothing produces no change
Compensation is a property defined by the logical consequences of combining more than one operation or more than one dimension.

Classification is another achievement of this period. This means that children acquire the skills they lead to the ability to describe things by terms of classes, numbers, and series.

Seriating occurs when a child can order objects in a series because they have acquired knowledge of them through experience. The picture above is an example of seriating. This child has arranged her dolls by height which is a form of seriation.

Formal Operations: After 11 and 12 Years

In this stage children develop abstract thought and can easily conserve and think logically in their mind. Children directly apply their logic to real objects or imagine objects. Those who are in this stage also develop propositional thinking. This type of thinking is not restricted to the consideration of the concrete or the potentially real but instead deals with hypothetics. Children in this stage can now reason from real to other possibilities.