Book excerpt: This anniversary edition—revised and updated—goes beyond raging hormones and peer pressure to explain why adolescents act the way they do and what parents and teachers can do about it. Why Do They Act That Way? was the first book to explain the scientific, brain-based reasons behind teens’ impulsive behavior, lack of focus, self-consciousness, territoriality, fatigue, and their quickness to anger and take risks—to name just a few common teen problems. Now, award-winning psychologist Dr. David Walsh has updated this classic with the latest research into the adolescent brain and the new challenges that they face with social media and the 24/7 online world. With practical advice and reassuring guidance, Walsh provides realistic solutions for dealing with every day and major challenges. As a parent, psychologist, coach, and trusted expert, Dr. Walsh offers the best advice to help adolescents thrive and parents survive.