Prefrontal cortex undergoes considerable development throughout adolescence which is not fully developed until around the early 20s. The prefrontal cortex is the part of the brain that allows people to think, evaluate, and make complex judgments in a uniquely human way. It underlies the increasingly complex intellectual achievements that are possible during adolescence. During adolescence, the prefrontal cortex becomes increasingly efficient in communicating with other parts of the brain. This helps build a communication system within the brain that is more distributed and sophisticated, permitting the different areas of the brain to process information more effectively.