Cognitively, adolescents become capable of abstract thought. Unlike their younger counterparts, adolescents can think about things that are not readily observable such as values, beliefs, theories, etc. The theorist Piaget called this ability to think in abstract terms formal operations. Propositional thought and hypothetico-deductive reasoning are also hallmark features of adolescent cognitive development.
Another cognitive ability that develops during this time is contemplative thought; i.e., the ability to reflect upon one's own thoughts, feelings, beliefs, intentions, and motivations; as well those of other people. However, exercising this new ability often increases youths' self-consciousness; believing that everyone else is closely observing them and scrutinizing their every move, or taking special notice of their appearance. Similarly, teenage youth believe their experiences are truly different and unique from anyone else's.
Adolescent cognitive development also includes advanced cognitive skills such as the ability to organize information in their minds, and an expanded capacity to commit things to memory. However, the part of the brain that makes rational decisions, the frontal lobe, isn't fully developed until the very end of the adolescent stage, so it may be difficult for youth to inhibit their impulses. This limitation explains why adolescents do not always make wise and healthy decisions.
Emotionally, the primary goal for adolescents is to develop emotional self-efficacy; i.e., a confidence in one's ability to identify and to express emotions in a positive and effective manner. This skill is essential for successful employment and rewarding social relationships. Another aspect of emotional maturity is the formation of an individual identity. Two developmental theorists, Erickson and Marcia, proposed that an individual identity emerges and then evolves during adolescence, but this evolution continues into adulthood. Both theorists concluded that while some adolescents are able to question and examine which set of values, characteristics, and beliefs best suit them, many other adolescents do not question or explore these areas at all. Many different factors can influence whether or not an adolescent will actively explore and determine a unique individual identity including: rigid family or cultural belief systems; chronic difficulty meeting basic needs (such as food, shelter, and safety); intellectual or developmental disabilities; and alcohol or other drug abuse during adolescence.
Socially, young adolescents begin to shift their attention away from their families and toward their network of friends. Teens' social networks provide the comfort, support, and guidance that were once provided by their family. Because of the increasing importance of friends, youth may struggle to "fit in," and may conform to peer pressure, whether or not this influence is a positive one. By late adolescence, friends will still fill an important social role in youths' lives; but generally, youth will choose to strengthen their ties to their families again.
Social relationships also change in quantity and quality. As adolescents become more emotionally mature, they become capable of deeper, more intimate relationships. Adolescents' relationships with other adults also change during this phase, as these relationships become more egalitarian and youth begin to shoulder a more equal responsibility for maintaining these relationships. Older adolescents begin to create mutually-beneficial, social networks with bosses, co-workers, and other acquaintances. Romantic interests and relationships are another important social development during adolescence. While youth are just beginning to experiment with these new relationships in early adolescence, many youth will build long-term commitments by late adolescence.