Cognitive Development, Ages 15 to 18 Years
By age 16, most teens are developing the ability to think abstractly, deal with several concepts at the same time, and imagine the future consequences of their actions. This type of thinking in a logical sequence continues to develop into adulthood.
Also by age 16, teens can learn to process more complex problems, to develop and test theories, to understand analogies, to reason inductively and deductively, and to think inferentially. They are better able to handle a more demanding high school curriculum because their memory and organizational abilities—such as time management, test preparation, and study skills—improve. Written and spoken language become more and more sophisticated. They may also begin to grasp political, moral, social, and philosophical concepts.
Most teens know the right thing to do. But their self-centered thoughts and behaviors may sway them to act with little thought about the end result. Bit by bit, their moral sense continues to evolve.
Sometimes teens grow a bit arrogant with their newfound mental abilities, and some parents complain that their teens "know everything." It can sometimes be difficult to deal with teens during this time because although they understand that others have differing viewpoints, they often firmly believe their own perception is the most true or valid.
Even though teens are forming adult cognitive abilities, they still do not have the life experiences to guide them in making the best choices. Indeed, adults struggle with this, too. They may reason that focusing on getting good grades in high school may further their academic future, but they might choose to spend their time working or socializing.
Researchers theorize that a teen's experiences determine, to a large degree, which connections in the brain are made stronger and which are "pruned," a sort of "use it or lose it" process. Researchers suggest that teens' accomplishments in sports or academics, for example, may positively affect the way they think for the rest of their lives. Advanced mental development may be the result of dramatic brain growth during puberty and then a refining process seen in the late teen years.