This is perhaps the most appropriate theory to apply when it comes to explaining about the impulsive behavior of adolescents. (Chapman, 2006) COGNITIVE THEORY by Jean Piaget

Piaget's cognitive theory discusses how a child thinks or how her mind works from birth to adulthood. She believes that development of the child is not a smooth task, but rather, a leap. There are new tasks that a child learns that marks the start of each stage. This theory seems to occur in a chronological order in a rigid but orderly manner. This can be a good tool in evaluation of the development of the cognition of a child. Her theory is useful in the educational world, and in helping the child learn about his environment. Her key ideas include adaptation in which one learns and adapts himself to his environment by means of assimilation and accommodation which go together.

At birth to two years old, the child learns about object permanence, wherein he learns to recognize the existence of an object despite it being not in his visual field. Not that because he could not see it that it does not exist. The child identifies himself as an agent of action and that an act is intentional. He thinks himself apart from other objects. This is the Sensorimotor stage. At two to seven years old is the Pre-operational stage where learning language is the main task and he uses this to identify objects around him. He still has an egocentric way of thinking and is able to classify objects by a single feature. Concrete operational is at seven to eleven years old when a child begins to think logically and can now classify and order objects by several features already. Formal operational is at eleven years and adulthood wherein a person is no capable of having abstract thinking. He can now test his hypothesis and issues he becomes concerned with are hypothetical and ideological in nature and he now begins to think about his future.

The ball existence experiment among babies below 6-month-old is a favorite experiment to prove the absence of object permanence which develops at sensorimotor stage. This stage is perhaps one of the most studied and shows how useful this theory is in developmental education. This stage not only tackled the biological aspect of development but also of cognition.

Preoperational stage is another useful stage among educators. Language is a big factor at this stage, and this is used to maximize the biological and neurological growth among children to which this stage belongs.

These are the developmental theories of the three psychologists. They have points of similarities and differences. Before discussing these, one must bear in mind that the theorists follow a certain way of thinking that is greatly influenced by the environment in his time.

Similarities in the theories include being organized in nature, that there are tasks in each stage, and the stages occur in succession. Second, in each stage, the theorists provide an explanation on why a certain task is included at a certain stage. Third, that each theory is rigid in a way that each stage coincides with a certain stage with no leeway for adjustments. (Atherton, 2005)

For the points in their differences, there are a number that can be noted. Freud is sexual in nature, Erikson is sociocultural...

Freudian believes that inability to achieve sexual gratification in each stage leads to fixation which manifests when an individual is already an adult, while Erikson believes that inability to hurdle the stages does not make an individual be stuck in that age, unlike Freud. Piaget however mentioned only absolute developmental milestones in each stage in her theory, not leaving any adjustments if there is retardation in development of a child. Among three, Erikson's is the most extensive among the three in its coverage of developmental theory, upon birth up to death and the most complete among the three, taking into consideration the social and cultural influences. However, Piaget's developmental theory is more evidence-based among the three with extensive clinical studies.
All these theories are contributory in understanding a child and an adolescent. As each individual grow, changes are happening in a very fast manner that guidance in emotional, religious social, psychological and cognitive aspects must be given. And these theories are extremely helpful in understanding a person at a certain stage in his life and useful in helping reach their potentials in life. An example of this is an adolescent. At twelve years of age, a person is most likely to be confused and lost, searching for his identity and identifying himself with a certain group of friends. There is an inner struggle for him also to establish himself apart from his family and friends and be accepted as himself. However, guidance and not imposition of authority and to add constant communication is a way to help this person. This is not applicable to a two-year-old child whose sense of self is egocentric and his moral fibers are not yet strong. Therefore a firmer approach is needed for his guidance. (http://www.etr.org/recapp/theories/AdolescentDevelopment/developmentalTheories.htm, 2007)

There is no single right theory to discuss development of a human being. It is not right to say that Piaget is right, nor Freud is wrong since different aspects of the human being was studied by each psychologists. Freud seems to give emphasis on emotional aspect, Erikson on social and cultural aspect and Piaget on cognitive aspect of growth. Therefore, the growth of an individual can be studied through the interaction of these three theories. Through this, if one aspect of an individual is experiencing a problem, an approach applicable to this problem derived from one of these theories can be used to address it.

2007) Developmental Theory: Theories and Approaches. ETR Associates. Retrieved May 4, 2008 on the World Wide Web: http://www.etr.org/recapp/theories/AdolescentDevelopment/developmentalTheories.htm

Atherton, J.,(2005) Learning and Teaching: Piaget's developmental theory Retrieved May 4, 2008 on the World Wide Web: http://www.learningandteaching.info/learning/piaget.htm

Chapman, a., (2006) Erikson's Psychosocial Theory of Development.

Retrieved May 4, 2008 on the World Wide Web: http://www.businessballs.com/erik_erikson_psychosocial_theory.htm

Stevenson, D., (1992) Freud's Psychosexual Stages of Development. Retrieved May 4, 2008 on the World Wide Web: http://www.victorianweb.org/science/freud/develop.html