Section 2 Introduction - Marking the end of the childhood years, the adolescent years come with rapid growth in the body and brain, transforming the child into a version of their adult selves. Many of the notable changes in this stage of life are due to the cognitive development that occurs in the individual. Teenagers are able to speculate, hypothesize, fantasize, compare alternatives, argue more effectively, plan ahead, and use abstract logic. However, they are still egocentric and lack life experience. In this section, you will learn about the many cognitive changes that come with the adolescent stage of development.