Piaget's Four Stages of Cognitive Development

Sensorimotor: Birth to Two Years

The progression during the sensorimotor stage witnesses the infant's development from purely reflexive and instinctual motor skills, to the early development of symbolic thought. According to Olson and Hergenhahn (2009), this stage is characterized by a lack of language. During this stage, the child develops a parameter by which to understand its environment by combining its sensory experience with physical actions. They see the entire world with only themselves as a frame of reference, and their world is the only one that exists.

Piaget thought the most significant accomplishment during this time was object permanence, which is accomplished when the child understands that objects maintain existence even though they may be hidden from sight. For example, before the end of this stage, the infant will learn to play peek-a-boo but will understand that her mother does not disappear when hiding under the blanket. The mother becomes permanent.

During this stage the child will begin to create habits and develop circular reactions in which the infant will learn to reproduce a particular event that initially occurred by chance. Infants become more object-oriented and replace self-preoccupa-tion with an interest in their environment. They also learn to repeat actions that produce pleasure and interest (Olson & Hergenhahn, 2009).

Piaget described the child as a young scientist conducting experiments on her environment to discover objects' properties and to solve problems and meet challenges. By the end of this stage, objects are separate from the child's sense of self and permanent.

Preoperational Stage: Two to Seven Years

The preoperational stage is marked by what Piaget described as a qualitatively new psychological functioning (Olson & Hergenhahn, 2009). The child learns to create and use representations of objects by drawings, words, and images, and begins to form stable concepts and mental reasoning along with beliefs that incorporate magical ideas. The child's thinking remains egocentric, and he has difficulty understanding the viewpoint of others. He still has difficulty performing mental tasks, and as such is "preoperational."

Even though children at this stage cannot use information in logical ways, they do begin to think in images and symbols. Their mental abilities include extensive use of language and pretend play.

At this stage, children will create complex pretend worlds and include everyone and everything around them in their fantasy. Between the ages of two and seven, children are still limited by egocentrism and animism, and demonstrate an inability to see the world from other than their own perspective. In their animistic belief, they may think the doll that fell off the shelf is mad at them for not having enough play time.

Between the ages of four and seven children begin primitive reasoning in which they become more inquisitive and curious. Centration and conservation are characteristic of children in the preoperational stage. Piaget demonstrated in his commonly known test of conservation believed that if a child does not understand the conservation-of-liquid task, they are still at the preoperational stage of cognitive development. Piaget thought children primarily learn through imitation and play during the sensorimotor and preoperational stages, as they create a vocabulary of symbolic images through internalized activity (Ginsburg & Opper, 1988).

Concrete Operational: Seven to Eleven Years

The third stage of cognitive development in Piaget's theory is concrete operational, which occurs between the ages of seven and 11 (Ginsburg & Opper, 1988). Children in this stage show intelligence through logical and systematic thinking that relates to concrete objects (Huitt & Hummel, 2003).

At this stage, children are no longer egocentric and can finally understand situations and events from someone else's perspective, and they no longer believe in animism. They will not think if the doll falls off the shelf, she is angry at the child for not playing with her. The child will check the doll's sitting place and put her back in a less precarious position, understanding logically why the doll may have fallen from the shelf.

Other accomplishments during this stage include seriation, in which the child can grade objects according to shape, size, or other characteristic. The child is likewise capable of classification, or classifying objects by the same criteria.

Children can understand conservation, or the idea that size, length, or number is unrelated to its appearance. The child is able to account for multiple aspects of a problem to find a solution. Children also understand transitivity and relationships of order, for example, if the first block is taller than the second block, and the second block is taller than the third block, then the first block is taller than the third block.

Children are capable of understanding reversibility and objects can be manipulated and changed, although later returned to their original state. In this stage, children remain limited to finding solutions to concrete problems but cannot yet, but cannot understand abstract concepts or accomplish hypothetical tasks (Olson & Hergenhahn, 2009).

Formal Operation: 11 through Adult

The fourth stage of Piaget's theory of development begins at age 11, but continues into adulthood. Intelligence is evident with the use of more complex logic and the use of symbols that relate to abstract ideas (Olson & Hergenhahn, 2009). According to Huitt and Hummel (2003), not all adults are capable of formal operations, and a mere 35% of high school graduates from industrialized countries reach this level of formal operational thinking.

In this stage, individuals gain the capacity to reason logically, think abstractly, and draw conclusions from ideas and information and can also apply these ideas and conclusions to hypothetical situations. This is evident in the new capacity for verbal problem solving, which becomes more logical and systematic. They can use hypothetical-deductive reasoning and as such, develop hypotheses, or systematically configure a path to the solution (Huitt & Hummel, 2003).

Adolescent egocentrism dominates adolescents' social thinking and they develop a heightened self-consciousness, which is apparent in their acute sense of personal uniqueness and invincibility. They become more able to understand abstract concepts such as love, morals, and values. Piaget believed understanding and using deductive logic was an essential part of accomplishing this stage. Many recall using deductive logic in hypothetical situations presented in high school science and mathematics classes. This stage enables the ability to reason contrary to fact, and adolescents in formal operational stage can use any statement as the basis of an argument whether it is true or false (Cherry, n.d.).