PIAGET'S STAGES OF COGNITIVE DEVELOPMENT

Piaget believed that cognitive development unfolds in a sequence of four stages. Each of the stages is age-related and consists of distinctive ways of thinking. It is the different way of thinking that makes one stage, discontinuous from and more advanced than an other. According to him, knowing more information does not make the child's thinking more advanced. The advance is qualitatively different.Piaget's four stages of cognitive development are described as under.

1.Sensorimotor Stage (Birth-2 years)

• Involves Senses and Motor Activity: This is the first Piagetian stage. It lasts from birth to about two years of age. In this stage infants understand the world by coordinating their sensory experiences (such as seeing and hearing) with their motor actions (such as moving, touching, tasting) hence the term sensori motor. At the beginning of this stage, infants show little more than reflexive patterns to adapt to the world. By the end of the stage, they display for more complex sensori motor patterns.
• Object Permanency: In the early period of this stage children behave as if objects that have disappeared from view have ceased to exist. "Out of sight out of mind" might be said to characterize the view of the infant. For example Piaget tells that an infant of five to eight months of age will loose interest and turn away of a cloth be thrown over the object before his hand reaches it. At a slightly older age, he is capable of seeking an object behind a screen. This involves understanding that objects and events continue to exist even when they cannot be seen, heard or touched. This important. cognitive accomplishment is called object permanency.
• Self and the World: According to Piaget the young infant does not differentiable between the self and the world. As a result his thoughts are chaotic, disorganized and unpredictable. This is what the mental level of a newborn is like. Gradually he realizes that there is a difference or boundary between oneself and the surrounding environment. Child shows curiosity to know the environment.

2.Pre-operational Stage (2-7years).

This is second Piagetain stage. It lasts from 2 year to seven yeas of age. Early childhood is the stage of preoperational stage. In this stage symbolic thoughts increases but operational thought is not yet present.

According to Piaget, operations are actions that are carried out and reversed mentally rather physically. The stage after sensori motor is called pre operational because the child has not yet mastered these mental operations but is moving towards mastery.

• Semiotic Function: According to Piaget, the first type of thinking that is separate from action involves making action schemes symbolic. The ability to form and use symbols, words, gestures, signs, images is the characteristic of this stage. This ability to work with symbols such as using the word "bicycle" or a picture of a bicycle to represent a real bicycle that is not actually present is called semiotic function. The child's earliest use of symbols is in pretending or mining. Children who are not able to talk will often use action symbols-pretending to drink from an empty cub or touching a comb to their hair showing that they know what each object is for.
• Development of Language: During preoperational stage, development of language is another characteristic. Between the ages 2-4years, most children enlarge their vocabulary from 200-2000 words.
• Difficulty in Conservation: Children do not understand the principles of conservation at this stage. Conservation is the principle that the amount or number of some thing remains the same if the arrangement or appearance is changed, as long as nothing is added and nothing is taken away.A classical example of difficulty with conservation is found in the preoperational child's response to the following Piagetain task.Leah, 5-years old, is shown two identical glasses, both short and wide in shape. Both have exactly the same amount of colored water in them. Interviewer: Does one glass have more water, or they have the same.              Same Leah: The experimenter then pours the water from one of the glasses into a taller, narrower glass.                 Interviewer: How, does one glass have more water or are they same?                Leah The tall one has more.        Interviewer: How do you know?                   Leah    It has the higher level.                                   Piaget's explanation for Leah's answer is that she is focusing (centering) attention on the dimension of height she has difficulty in considering more than one aspect of a situation at a time (descending). The preoperational child can not understand that increased diameter compensated for decreased height because this requires thinking two dimensions at one time.
• Egocentricism: Another characteristic of this stage is that pre- operational children are egocentric. It means they tend to see the world and experiences of the others from their own view point. It simply means children often assume that every one also shares their feelings, reactions and perspectives. For example if a little boy at this stage is afraid of dogs, he may assume that all children share this fear.
• Animism:Animism is another characteristic of this stage. Children between four to six years of age, regard every thing to be alive unless it is broken or damaged. Children up to seven years regard every thing that moves to be alive. For children of eight to ten years, every thing that moves by itself is alive. Children at late child hood stage, reserve life for animals and plants or animals alone.

The concrete operational stage, the third Piagetian stage of cognitive development, lasts from about seven to about eleven years of age. Concrete operational thought involves using operations. Logical reasoning replaces intuitive reasoning, but only in concrete situations. Classification skills are present, but abstract problems go unsolved

3.  The Concrete Operational Stag (7-11 years):

• Principle of Conservation: A concrete operation is a reversible mental action pertaining to real, concrete objects. Concrete operations allow the child to coordinate several characteristics rather than focus on a single property of an object. At the concrete operational level, children can do mentally what they previously could do only physically, and they can reverse concrete operations. For example, to test conservation of matter, the child is presented with two identical balls of clay. The experimenter rolls one ball into a long, thin shape. The child is asked if there is more clay in the ball or in the long, thin piece of clay. By the time children are seven or eight years old, most answer that the amount of clay is the same. To answer this problem correctly, children have to imagine that the clay ball can be rolled out into a long, thin strip and then returned to its original round shape. In this example, the preoperational child would have focused either on height or length. The concrete operational child coordinates information about both dimensions.
• Classification: An important concrete operation is classifying or dividing things into different sets or subsets and considering their interrelationships. Reasoning about a family tree of four generations reveals a child's concrete operational skills. The family tree suggests that the grandfather (A) has three children (B, C, and D), each of whom has two children (Ethrough J), and one of these children (j) has three children" (K, L, and M). Concrete operational thinkers understand the classification, For example, they can reason that person J can at the same time be father, brother, and grandson. A preoperational thinker cannot.
• Seriation: Some Piagetian tasks require children to reason about relations between classes. One such task is seriation, the concrete operation that involves ordering stimuli along some quantitative dimension (such as length). To see if students can serialize, a teacher might place eight sticks of different lengths in a haphazard way on a table. The teacher then asks the student to order the sticks by length. Many young children end up with two or three small groups of "big" sticks or "little" sticks rather than a correct ordering of all eight sticks. Another mistaken strategy they use is to evenly line up the tops to the sticks but ignore the bottoms. The concrete operational thinker simultaneously understands that each slick must be longer than the one that precedes it and shorter than the one that follows it.
• Transitivity: Another aspect of reasoning about the relations between classes is transitivity. This involves the ability to logically combine relations understand certain conclusions. In this case, consider three sticks (A, B, and C) of differing lengths. A is the longest, B is intermediate in length, and C is the shortest. Does the child understand that if A> B, and B > C then A > C? In Piaget's theory, concrete operational thinkers do; preoperational thinkers do not.

4.The Formal Operational Stage (11-15 Years):

The formal operational stage, which emerges at about eleven to fifteen years of age, is Piaget's fourth and final cognitive stage. At this stage, individuals move beyond reasoning only about concrete experiences and think in more abstract, idealistic, and logical ways.

• Abstract Thinking: The abstract quality of formal operational thinking is evident in verbal problem solving. The concrete operational thinker needs to see the concrete elements A, B, and C to make the logical inference that if A = B and B = C, then A = C. In contrast, the formal operational thinker can solve this problem when it is verbally presented.
• Ideal and Imaginative Thinking: Accompanying the abstract nature of formal operational thought are the abilities to idealize and imagine possibilities. At this stage, adolescents engage in extended speculation about the ideal qualities they desire in themselves and others. These idealistic thoughts can merge into fantasy. Many adolescents become impatient with their new found ideals and the problems of how to live them out.
• Logical Thinking: At the same time as adolescents are thinking more abstractly and idealistically, they also are beginning to think more logically. As formal operational thinkers, they think more like scientists. They devise plans to solve problems and systematically test solutions. Piaget's term hypothetical-deductive reasoning embodies the concept that adolescents can develop hypotheses (best hunches) about ways to solve problems and systematically reach a conclusion. Example:One example of hypothetical-deductive reasoning involves a modification of the familiar game "Twenty Questions." Individuals are shown a set of 42 color pictures displayed in a rectangular array (six rows of seven pictures each) and asked to determine which picture the experimenter has in mind (that is, which is "correct"). The subjects are only allowed to ask questions to which the experimenter can answer yes or no. The object of the game is to select the correct picture by asking as few questions as possible.Adolescents who are deductive hypothesis testers formulate a plan and test a series in hypotheses which considerably narrows the field of choices The most effective plan is a "halving" strategy (Q: Is the picture in the right half of the array? No. Q: OK. Is it in the top half? And so on). A correct halving strategy guarantees the answer in seven questions or less. In contrast, the concrete operational thinker might persist with questions that continue to test some of the same possibilities that previous questions could have eliminated. For example, they might ask whether the correct picture is in row 1 and are told that it is not. Later, they ask whether the picture is A, which is in row 1.Thus, formal operational thinkers test their hypotheses with judiciously chosen questions and tests. In contrast, concrete operational thinkers often fail to understand the relation between a hypothesis and a well-chosen test of it, stubbornly clinging to ideas that already have been discounted.
• Adolescent Ego-centricism: A form of egocentrism also emerges in · adolescence. Adolescent ego-centrism is the heightened self-consciousness that is reflected in adolescents' beliefs that others are as interested in them as they themselves are. Adolescent egocentrism also includes a sense of personal uniqueness. It involves the desire to be noticed, visible, and "on stage."Egocentrism is a normal adolescent occurrence, more common in the middle school than in high school years. However, for some individuals, adolescent egocentrism can contribute to reckless behavior, including suicidal thoughts, drug use. Egocentricity leads some adolescents to think that they are invulnerable.