According to Piaget, during adolescence, young people become better able to speculate, hypothesize, and fantasize, emphasizing possibility more than reality. Unlike the younger child, whose thought is tied to concrete operations, adolescents can build formal systems and general theories that transcend, and sometimes ignore, practical experience. Their reasoning is formal and abstract, rather than empirical and concrete.
Piaget also states that students in grades 9-12 would be in the Formal Operational stage of intellectual development. The students at this stage have cognitive structures that include conceptional reasoning much more like an adult. Students at this stage become more independent and logical in their thinking. They are able to think abstractly, form hypothesis and test, make generalizations, reason logically, form different view points, and develop ideals.
Another characteristic of adolescent thought is a particular form of egocentrism that leads young people to overestimate their significance to others. This characteristic is sometimes expressed in a personal exaggeration about the grand and glorious deeds they will perform in adulthood.
According to Erickson, students in grades 9-12 would be in the Adolescent stage (12-18 years) of intellectual development. Students in the Adolescent stage are primarily concerned with searching for their own identity. They need to make decisions and choices about themselves and their lifestyles. They begin to see themselves as separate from their parents.
Moral reasoning also becomes more complex during adolescence, for the young person who can grasp general laws of physics or principles of logic is more likely to articulate moral laws and ethical principles. Most adolescents question traditional customs and laws, although none achieve an understanding of universal moral principles, the last of Kohlberg's six stages. However, people exhibit more advanced behavior when tests of moral reasoning are based on familiar experiences.
Vygotsky believes that social interaction is a very important role in the development of cognition. The roles of the surrounding social and cultural context are fundamental in the initial development of knowledge. When learners are first introduced to a problem, they rely on adults, parents, teachers, and their peers. Initially the person(s) interacting with learners assumes most of the responsibility for guiding the problem solving. Language is the principle form of communication in which adults share their rich knowledge. As a result, the learners' language expands and they internalize this new knowledge as their own. They take this new internalized knowledge and apply it to a similar problem-solving situation. Vygotsky termed this process as "the zone of proximal development. It is the difference between learners can do independently and what can be accomplished cognitively with scaffolding from more knowledgeable others. As the learners gain knowledge through scaffolding the difference is minimized, and the learners become more independent.
One of the major goals of adolescence is identity achievement, the development of the young person's own sense of self. Identity formation can be affected by personal factors, including relationships with family and peers, the nature of the society, and the economic and political circumstances of the times. During adolescence, the peer group becomes increasingly important in helping adolescents to become more independent to try new behaviors and explore different facets of their personality.